How much power do engine mods yield?

[Serj22]

Guess that's your perogative, sounds like a diesel and a leafblower had a baby to me. Plus it don't have a cool lumpy idle. If I wanted something that whined all the time I'd get a wife, but to each their own I s'pose!

Yeah, but it was the child of a sexy leafblower and a manly diesel.

You can't knock it till you try it Brandon, and I know that turbo slant you were building squished fluffy and all, but maybe it's time to move past it and give it a shot?

 

[AJ/FormS]

Oh-Oh

I heard it. 50% hi-way at 55mph.
Ima thinkin 3.55s might be too much. That'd be about 2750rpm. I know the slanty is pretty smooth(by design), but 2750 is still up there. 3.23s will pull it down to around 2500@55. If you are concerned about fuel economy, then that 250 rpm is valuable. If you are spending a lot of time on the hi-way then even the 3.23s might be too much.
In that case if it were mine, I would bump the Scr up.With no other mods, yet. I would bump the Dcr up to 8.5 or so. Then a sharp tune.
That is what I did to the 225 in my 80 Volare. This gave me a lot more punch off the line, and I was able to keep the 2.76 gears.Then later,I swapped in a wide-ratio tranny with a loc-up. This gave me even more snap;and hi-way cruising with 2.76s, a loc-up and taller tires gave me 2270@65.
In this case the new low gear in the tranny gave me 12% more take-off torque, the loc-up T/C was about 300 rpm more stall with the higher c/r, so thats more snap. And the additional engine c/r brought yet more torque to the table.
With just these changes, The take-off was snappy,and the hi-way economy was much improved. The wider tranny ratios, were hardly noticed.
I spent a lot of time on the tune, but it was well worth it. I still have this car, but the body is gone, so I didnt register it this year, for the first time since 1995.
So in this case, Torque was increased with compression. Take-off was improved with; engine torque, TC stall,and tranny gearzzzz . Rpm on high-way was decreased with the loc-up. Fuel economy was improved with the increased compression, the lower running rpm and the tune.
Notice, no where is there a cam or a carb or an exhaust change.
The engine will have the same personality as before, just bigger. I venture to say that 80% or more of the time, your engine will be spinning at less that 3500rpm.If thats true,IMHO, it doesnt need a cam or a carb and perhaps not even a bigger exhaust.
Eventually, I installed a bigger, solid-lifter cam. With it went the Super-six stuff. Well, that was a bit of a step backwards, in terms of take-off. Yeah, it was better able to pass at higher speeds, but it was definitely softer on the take-off. It really wanted gears. But it wasnt soft enough to warrant changing. I left it that way for many years.
This was my experience.
Again, all the best to you,whatsoever you choose.

 

[Bill Dedman]

I pulled this posting from the forum and was wondering how much extra power you're going to get with mods like this...
I don't want to swap the engine, I really dig the slant 6!

The interesting fact is; the slant six can have multiple "personalities," not unlike a person who's schizophrenic and can display different and variable behaviors at different times. We have all seen movies that feature a person, (usually a woman, for some unknown reason,) who exhibits dramatically-altered personalities at random times... so much so that they seem to be totally-different people.

The slant six was mandated, by the "front office" at Chrysler, to power the new Valiant for 1960. The powers-that-be, (at the time,) specified in no uncertain terms, that it WAS going to be powered by an inline six, and that new overhead-valve engine would be as short as physically possible from the fan to the flywheel, and be "short," top-to-bottom (for a low hood-line.) . This meant "thinking outside the box" on engine design, so the design-engineers laid the engine on its side (30-degrees,) and moved the water pump from the end of the engine to its side... making it both lower and shorter, front-to-rear. Additionally, the design engineers specified that the bores of this new engine be only 3.4", in yet another effort to make it as short (front-to-rear) as possible.

This design strategy had several results; some good... some not-so-good.

It WAS short, for sure, and that made it possible to fit it into the engine bay of the new Valiant with room to spare... exactly as the front office had asked for.

The 170 cubic-inch version was a great-performing "economy" engine, and had performance potential that was exceptional, with HyperPak 170 slant six Valiants embarrasssing G.M. and Ford so badly at the "compact" race at Daytona Beach (N.A.S.C.A.R.,) that the officials who ran the racing program CANCELED any further "compact" races for the following year...

So far, so good...

But, when the need for an engine that would pull around the bulk and weight of the full-sized Mopars of the day resulted in a ONE-INCH stroke increase of the 170 (resulting in a 225 cubic-inch motor,) nothing was done to the cylinder-head to improve its ability to "breathe," and that situation has never changed, to this day.

Naturally-aspirated, the 225 motor is a full 1/3 larger than the 170 with the same breathing apparatus (ports and valve sizes.)

That just doesn't work for what we like to call "high-performance."

To give you a telling example of the breathing situation of the 225 motor, it is interesting to compare that engine with the 302 (5-liter) Chevy V8 Z-28.

Each motor has approximately 38 cubic inches per cylinder.

Slant 6 valves are 1.62" on the intake; the biggest valves that fit without "heroic measures" are 1.75". STOCK Chevy valves on the intake are 2.02".

The exhaust side is a little better, but not much. The stock slant six exhaust-valves are 1.36" with an increase to an aftermarket 1.5" with the STOCK Chevy exhaust valve diameter being 1.6".

You can see the problem... The best-flowing 225 reworked heads come in at around 220cfm on the intake side, with the Chevys at over 280cfm... on the same-size cylinders.

There is just NO WAY to get the kind of per-cubic-inch performance out of a naturally-aspirated slant six that will give you much over 300 horsepower, if that... No amount of scienced-out intake-system, headers, cam design, rpm's, nor high compression will result in stellar performance, because it will always be defeated by that OEM, "170" cylinder head.

Now, 300 horsepower will result in an A Body such as 805 Mopar Kid's '68 Dart going 14-flat at almost 100 mph. That sort of acceleration is, arguably, a few car-lengths faster than, say a bone-stock 340 Duster.

But, it takes a full-race engine with a rough idle and some poor gas mileage to get that 14-flat.

Of course, you can build a car with more friendly road manners and better gas mileage that will run 15-flat.

But, if a 14-flat isn't fast enough for you, there is always, forced-induction.

Slant sixes are especially well-suited for supercharging/turbocharging, and I imagine Nitrous, although I don't know anything about the laughing gas...

What makes them especially well-suited for forced-induction is the layout of the block structure; because they were originally designed to be made of aluminum, the main-bearing webs, the outside of the block (walls) and the deck surfaces, are especially thick. The aluminum plans got shelved after some 55,000 copies, (due to production problems,) and they reverted back to all cast-iron construction. But, very little was changed, so the thicker material specs remained, making for an engine that is more like a Diesel than a gasoline engine...

In the real world, that means a slant six is one sturdy little engine, with a short, forged steel crankshaft, and main bearings the size of a Hemi's.

I have a friend who has experimented with high boost-levels on his turbocharged slant six... so far he has utilized 37 pounds without engine failure. Don't try that with your V-8....

But, there have been two engines (both FABO MEMBERS,) that have videos that show their cars running the quarter-mile at over 120mph, which requires about 500+ horsepower...

The turbo engines, as I see it, can be built two ways, with two different levels of performance: You can put together a low-boost (under 15 pounds,) turbo motor, with stock everything (pistons, rods, valves, cam etc.) and enjoy a pump-gas motor that will move your A Body in the low 13's at a little over 100mph, OR you can build it (for a LOT more money,) with forged pistons and rods, and run it on race gas and play with the "big boys" at speeds of 120mph+ and quarter-mile e.t.s of 11-flat and sometimes better.

You pays your money and, you takes your choice.

But, in EACH CASE, you get to KEEP your slant six!!! No engine-swapping needed!

The Jeckyll/Hyde facet of this high-horsepower motor lies in its cam selection; the best running turbo slants idle like a stock motor at about 600 rpm, and have loads of mid-range torque. They are all done by 5,500 rpm, which, since the torque and horsepower figures always cross on a performance-graph at 5,250 rpm, means that these engines make over 500 pounds-feet of torque at about 5,000 rpm... That indicares a mild motor with excellent road manners, but with terrifying acceleration... a "split-personality.":twisted: LOL!

Turbo- (or, supercharging,) is neither cheap, nor easy.... but, it will provide results that you can't get anywhere else with a slant six! It's all about moving air through THAT HEAD!!!!

 

[Bill Dedman]

Yeah, but it was the child of a sexy leafblower and a manly diesel.

You can't knock it till you try it Brandon, and I know that turbo slant you were building squished fluffy and all, but maybe it's time to move past it and give it a shot?

What he said...

 

[RustyRatRod]

The 302 to slant comparison is about like comparing a nun to a 10 dollar street walker. It doesn't fly. The bore sizes are so different, no way in heck would the flow comparisons even be close. Ever. Find something else to pound on. That doesn't work.

 

[Bill Dedman]

The 302 to slant comparison is about like comparing a nun to a 10 dollar street walker. It doesn't fly. The bore sizes are so different, no way in heck would the flow comparisons even be close. Ever. Find something else to pound on. That doesn't work.

THAT was my whole point, Einstein. There is NO ROOM for big valves in a slant motor because the bore centers are too close; only 4"... The Chevy small block is 4.4".

That is why they will never run, naturally-aspirated.

Maybe, someday, if somebody designs and produces a 4-valve head for this block, it will have a chance to breathe, but until then, forced induction (or N2O) is the only way...

 

[RustyRatRod]

THAT was my whole point, Einstein. There is NO ROOM for big valves in a slant motor because the bore centers are too close; only 4"... The Chevy small block is 4.4".

That is why they will never run, naturally-aspirated.

Maybe, someday, if somebody designs and produces a 4-valve head for this block, it will have a chance to breathe, but until then, forced induction (or N2O) is the only way...

blah blah blah blah blah blah.

lol

you know I love you Bill. LOL

 

[Killer6]

First up, I would like to see which OE chevy heads flowed 280CFM,even modified.Like
none.Even admitted by their most avid supporters,an "all out" unit from the day is
lucky to post 250CFM,backed up by Smokey Yunick himself.I again take issue w/
the notion that the slanty head sucks,simply because it doesn't.Yes, the bore is a
definite restriction,and if ma mopar had cast a little more meat on the long side of
the pocket,things could be better.But valve size isn't the only factor,and the shape
and orientation of the slanty port has a superior discharge coefficient compared to
other ports w/larger valves, and swirl properties as well. The small bore/chamber is an excellent deterrent to detonation, as is the spark plug location,even w/o a
"squish" to speed up combustion.Is the 225 ever going to be a high rev monster?No.
But name how many 400HP 302 fords&chevies are running around w/o bigass cams,
steep gears,and loooooose converters,like none.Of course excluding anything with
modern variable intakes&cams etc.,which is kind of like cheating,but we'd all take a
retrofit system in a second if an affordable/viable one ever appeared!
Secondly,I'm done to death w/the "torque vs. HP" canard, there is no such thing.
More torque IS more HP, and so is the same torque at a higher RPM,they can't be
exclusive.The question is not improving torque, but efficiency at the desired RPM
range you wish to operate your engine in.You either want more efficiency at low
RPM,or higher RPM.Some improvements benefit BOTH,which are the ones you
really want.Such as compression,larger valves,and any fuel/ignition optimization,
along with exh. improvements.High RPM's go faster,but generally require sacrifice
in a whole bunch of areas,and there is a limit to whats tolerable for everybody.
Whats yours? Sounds like You know where you're headed,so best of luck to you,
:coffee2:

 

[Bill Dedman]

:banghead:

.....................................................................................................................

 

[Bill Dedman]

First up, I would like to see which OE chevy heads flowed 280CFM,even modified.Like none.Even admitted by their most avid supporters,an "all out" unit from the day is lucky to post 250CFM,backed up by Smokey Yunick himself.I again take issue of the notion that the slanty head sucks,simply because it doesn't.Yes, the bore is a
definite restriction,and if ma mopar had cast a little more meat on the long side of
the pocket,things could be better.But valve size isn't the only factor,and the shape
and orientation of the slanty port has a superior discharge coefficient compared to
other ports w/larger valves, and swirl properties as well. The small bore/chamber is an excellent deterrent to detonation, as is the spark plug location,even w/o a
"squish" to speed up combustion.Is the 225 ever going to be a high rev monster?No.
But name how many 400HP 302 fords&chevies are running around w/o bigass cams,
steep gears,and loooooose converters,like none.Of course excluding anything with
modern variable intakes&cams etc.,which is kind of like cheating,but we'd all take a
retrofit system in a second if an affordable/viable one ever appeared!
Secondly,I'm done to death w/the "torque vs. HP" canard, there is no such thing.
More torque IS more HP, and so is the same torque at a higher RPM,they can't be
exclusive.The question is not improving torque, but efficiency at the desired RPM
range you wish to operate your engine in.You either want more efficiency at low
RPM,or higher RPM.Some improvements benefit BOTH,which are the ones you
really want.Such as compression,larger valves,and any fuel/ignition optimization,
along with exh. improvements.High RPM's go faster,but generally require sacrifice
in a whole bunch of areas,and there is a limit to whats tolerable for everybody.
Whats yours? Sounds like You know where you're headed,so best of luck to you,
:coffee2:

Killer6,

I am in no position to argue the subtile shapings of intake ports of which you speak, because I have never even used a flow bench; all I see are results... but, I see a lot of those. You may remember a FABO member (805 Mopar Kid) who had an interest in naturally-aspirated, slant sixes. He worked at an automotive modification facility, and his daily-driver was a 1968 Dart with a modified 225 slant six. He wrote on this forum, at length, about the many modifications he made to that Dart, which included better intake plumbing (carbureted,) a freer-flowing header-based exhaust system, a fully-ported cylinder head with bigger valves, higher compression, stronger valve springs, a deeper rear-end gear, drag slicks, a higher-stall torque converter, a shift-kit for the 904, and a whole bevy of performance mods I have obviously forgotten.

It was pretty much an all-out effort to go fast,in a mid-sixties A-body.

After he had spent lots and lots of hours, modifying this car for drag racing, it was a whole lot faster than a stock slant six 225 1968 Dart..... at 14-flat and 98mph.

I took my 1964 Valiant out for the first time a few weeks ago, and with "only" ten pounds of boost, ran 13.50. And, that was with a very poor 2.1-second, 60-foot time.

I was not very proud of that time, but my engine is (hopefully) going to run a whole lot faster/quicker, once I raise the boost level to something more productive, like 15 or 20 pounds, assuming I don't blow it sky-high, between now and then.
It just seems to me, that, going fast is a whole lot harder with a naturally-aspirated slant six than is should be.... and, I am pretty-sure that the small ports and valves we're stuck with, is the problem...

That is the crux of my argument. The engine in 805 Mpar Kid's Dart made about 300 hp. It was at the modification-level that the next significant gain in horsepower was going to cost a big chunk of change.

Three hundred horsepower from a turbocharged slant six is just over half what they can produce, with the right parts, and with a 5,500rpm redline and a smooth idle.

It's not easy and it's not cheap, but like I said, it's arguably, the best way to outrageous performance with one of these beasts...:cheers:

 

[dennday67]

I also have been thinking about adding a turbo to my slant six. Swapping out the Holley 1945 to the Holley 350 made the slant six feel like a whole different motor.

 

[Serj22]

I also have been thinking about adding a turbo to my slant six. Swapping out the Holley 1945 to the Holley 350 made the slant six feel like a whole different motor.

I'm using this carburetor for my slant six turbo, the 350. I show how i modified it on my build page. It works great.

 

[Brandon Weaver]

I love how if a n/a slant runs 14s, and its 'topped out' at '300 horse', but a slant runs a 12 somethin and its 'blazin fast' but is actually MEASURED at 300 horse. As in, like, dyno proven. But the slant that runs 14s on all motor has never been MEASURED, its just ASSUMED that it makes 300 and can't go any faster. Must be cuz it ain't got a snail on the side.

I think if two people build two slants, one turbo and one n/a, and they both make 225hp, one of em don't know how engines work, much less how to build one.

Oh, and the 'don't knock it till you try it' rings a bit hypocritical to me, seeing how you have yet to build a one on all motor... Btw, meth ain't all bad, don't knock it till you try it! Oh, and the most powerful slant was somewhere around 370.

Another thread, completely wrecked by fanboys...

 

[Killer6]

Killer6,

It was pretty much an all-out effort to go fast,in a mid-sixties A-body.

After he had spent lots and lots of hours, modifying this car for drag racing, it was a whole lot faster than a stock slant six 225 1968 Dart..... at 14-flat and 98mph.

It just seems to me, that, going fast is a whole lot harder with a naturally-aspirated slant six than is should be.... and, I am pretty-sure that the small ports and valves we're stuck with, is the problem...:cheers:

A 98mph trap speed should net a 13.60 ET w/a dialed in drivetrain/chassis setup.
Assuming an as raced wt. of 3000lbs.w/driver and a full tank,that would tick off at
230hp at the wheels,use any"at the crank"guestimations at your own risk.Now,this
is theoretical,but has been proven in practice enuff to be accepted..follow;220CFM
is capable of supporting approx.440hp in a V-8 w/a fairly aggressive cam profile.
More for rollers,less for street cams,that is the "rule of thumb",and theres specific
formulas for these numbers.But we all know that isn't how it goes in the real world
and combustion chambers,plug location,thermal layout,etc.,etc.,all alter the real
output.Plugging in 220CFM still gives you a 330HP potential,and I'm sure some
have bumped up against that.Still,at 300HP for a punched /6,that would be more
like 574HP if it were a 440,so the real problem is simply uh,the engine is small!
You have no trouble convincing me about the beauty of turbos,I got hooked on
them when I worked at a CPD dealer in '86,and I own a number of them.I am
picking up another 170 for such a project,slated for a '64 GT conv.,but the coupe
is getting the orig. .060" over 225 I built yrs. ago w/some definite improvements.
And my '90 omni has a 2.5turbo voyager drivetrain waiting to go in........

 

[Serj22]

I love how if a n/a slant runs 14s, and its 'topped out' at '300 horse', but a slant runs a 12 somethin and its 'blazin fast' but is actually MEASURED at 300 horse. As in, like, dyno proven. But the slant that runs 14s on all motor has never been MEASURED, its just ASSUMED that it makes 300 and can't go any faster. Must be cuz it ain't got a snail on the side.

I think if two people build two slants, one turbo and one n/a, and they both make 225hp, one of em don't know how engines work, much less how to build one.

Oh, and the 'don't knock it till you try it' rings a bit hypocritical to me, seeing how you have yet to build a one on all motor... Btw, meth ain't all bad, don't knock it till you try it! Oh, and the most powerful slant was somewhere around 370.

Another thread, completely wrecked by fanboys...

I do not think you got that my post towards you was lighthearted and not intended to be mean.

To be honest, my engine is stock, save for a bit of head work, stock cam, etc... just has a turbo bolted to it. It works, but the block is full of junk, so I've purchased another engine from an 80s vehicle, to drop it in the car, while i pull the 68 block out and rebuild it. I'm going to go turbo again, just because I like it. It's interesting. Maybe it doesn't make as much power as an N/A slant built by someone else, but it makes me happy.

 

[nm9stheham]

Back to the OP's question....and the rear gears. I have a '62 Dart with the stock 3.31 rear gears and it is turning over 300 rpm at 70 MPH, and is probably edging into the power valve some. It is not all that great for a cruising combo. I have a 2.94 rear gear set that I'll eventually put in and live with the lower wheel torque. But this car is a grocery-getter, not a hot rod, so what the OP wants is the most important.

So if the OP is going be doing a lot of interstate driving, and has an auto trans car it probably has 2.94 or 2.76 rear gear and it would be good to stick with that for interstate use. If his driving is all in town, then a steeper gear would be nice. For mixed town and highway, then I would go with a steeper rear (like 3.23, and maaaaybe 3.55) and convert to the 4 speed OD trans to help keep the interstate RPM's down.

BTW the original list of mods looks good per wide experience, with the dual exhaust being for the header as said.

 

[dennday67]

I'm using this carburetor for my slant six turbo, the 350. I show how i modified it on my build page. It works great.

Ill have to check out your build for lots of ideas.

 

[Bill Dedman]

A 98mph trap speed should net a 13.60 ET w/a dialed in drivetrain/chassis setup.
Assuming an as raced wt. of 3000lbs.w/driver and a full tank,that would tick off at
230hp at the wheels,use any"at the crank"guestimations at your own risk.Now,this
is theoretical,but has been proven in practice enuff to be accepted..follow;220CFM
is capable of supporting approx.440hp in a V-8 w/a fairly aggressive cam profile.
More for rollers,less for street cams,that is the "rule of thumb",and theres specific
formulas for these numbers.But we all know that isn't how it goes in the real world
and combustion chambers,plug location,thermal layout,etc.,etc.,all alter the real
output.Plugging in 220CFM still gives you a 330HP potential,and I'm sure some
have bumped up against that.Still,at 300HP for a punched /6,that would be more
like 574HP if it were a 440,so the real problem is simply uh,the engine is small!
You have no trouble convincing me about the beauty of turbos,I got hooked on
them when I worked at a CPD dealer in '86,and I own a number of them.I am
picking up another 170 for such a project,slated for a '64 GT conv.,but the coupe
is getting the orig. .060" over 225 I built yrs. ago w/some definite improvements.
And my '90 omni has a 2.5turbo voyager drivetrain waiting to go in........

All of your performance "assumptions" seem pretty realistic to me, and I have no argument with any of them. Your estimate of 230 rear wheel horsepower seems low until you consider that it is, in fact, rear wheel horsepower, having gone through a converter, an automatic transmission, two U-joints and a ring and pinion, and is still over one horsepower per-cubic inch, AND is naturally-aspirated, it seems pretty good, considering that pitiful cylinder head.

I use an online program called "Wallace Racing Calculators" which seems to work well for estimating power output from hypothetical engines and estimates of eighth- and quarter-mile e.t.s if you supply numbers for car weights.


I am sure it is not 100% accurate, but works well for comparing outputs of different combinations of powertrains and vehicle weights.

It has a lot of different inputs to show a variety of performance specs using any parameters you'd care to input.

The two turbo slant six cars that I have paid a LOT of attention to on this site, each have turbocharged 225 motors, and when I enter the specs of their drag strip runs along with their weights, they both calculate to numbers in the low 500-horsepower range. That's about 2.17 horsepower per cubic inch, or about 131 horsepower per liter.

In defense of that number, I would like to ask poster Brandon Weaver how he arrived at his contention that "the most powerful slant was somewhere around 370."

My argument is supported by this video: [ame="https://www.youtube.com/watch?v=7QzUfV8iTpQ"]Turbo Slant Six 10.74 @ 127 mph 7-19-10 - YouTube[/ame]

wherein a 2,800-pound '66 Valiant (2,970 pounds with driver) runs 127mph in the quarter-mile.

I don't see how that would be possible with 370 horsepower.

Tom Wolfe's similar engine makes approximately the same amout of power, pulling his 400-pound heavier '70 Dart 120 mph in the quarter.

Cameron Tilley's Australian Valiant reputedly has over 600 horsepower, do, I dunno... So far, a 500-horsepower figure has not come out of an engine-dyno test, so until it does, I guess we won't really know...

But, it's fun to compare and analyze...:burnout:

 

[Bill Dedman]

Oh, and the most powerful slant was somewhere around 370.

Another thread, completely wrecked by fanboys...

Just for fun, I went to my favorite website that "computes" speeds and elapsed times, based on horsepower and weight, just to see what THEIR computations would contend, for a drag car that had 370 horsepower and weighed 3,170 pounds.

They believe it should run about 11.92 at 112 mph.

That assumes that the chassis has been optimized and there is no wheespin present.

The run that Ryan's car made (on the video) requires 500 horsepower to go 10.55 @ 127mph.

Ryan's car has a 727 transmission, and the excessive rotating weight (compared to a 904,) MIGHT be worth enough e.t. to have slowed his car from thr 10.55-seconds, to the 10.74 he actually turned on that run. Just guessing, but, it makes a lot of sense....

Tom Wolfe's car is a later-model Dart (1970,) so, is heavier, but with approximately the same engine specs. lets see what the Wallace program says about it's engine's output.

It goes 120 mph in 11-seconds flat, in the video. The Dart weighs 3,200 pounds, plus Tom's 170 pounds... that's 3,370.

The figures compute to 11.00-seconds and 121.77 mph for 500-horsepower, so the Wallace program apparently believes that the two engines in these two cars are virtually identical in their output.

That's 500 horsepower, each. Both run about 28 pounds of boost.

I only hope that MY engine will evenually run within one second of either of them...

If it will, I'll be a happy camper!!!rayer:rayer:rayer:

Am I the only one here who has NO IDEA what a "fanboy" is????

 

[kesteb]

Reportedly Tilly is doing that on 18psi of boost. On the The H,A,M,B there is a thread on six cylinder drag cars from the '70s on. These are mostly class racers. There are reported A-Bodies running 11's, 12's and 13 second times. Class racing doesn't involve nitrous or turbos just very detailed and thought out combinations. How did they do it, who knows those guys don't post on the Internet and didn't share secrets.

Don Dolmetch has been running a 225 powerd FED dragster as a hobby. He has been building engines for a long time. He has some threads on the H.A.M.B detailing what he has done to the engine. His ideas and experimentation has definitely gone down a different path then most. His contention is that the head is not a bad as some have proclaimed. With a proper port job and cam, the 4.125" stroke is actaully a benefit to filling the cylinder. He may be onto something, his dragster is able to run with other cars with twice the engine size and he proclaims that it is "scary" fast.

My own experimentation has shown me that the 225 doesn't respond like a v8 would with a given combination. For an example, many have said that the stock fuel pump and fuel lines are more then good enough. I have found that they are marginal at best.

 

[64DartGTinAZ]

Am I the only one here who has NO IDEA what a "fanboy" is????

Here you go, Bill: http://www.urbandictionary.com/define.php?term=fanboy

 

[Bill Dedman]

Here you go, Bill: http://www.urbandictionary.com/define.php?term=fanboy

Thanks, 64DaertGTin AZ.

Now I know how I must sound to other people.

My apologies... I try not to be a "fanboy" by backing my contentions up with various and sundry "facts and figures," such as the Wallace website computations and the videos that show the cars I champion, running really fast, but I must do a very poor job of presenting my arguments if my descriptions and performance results come off as "fanboy" prattle...

Soon, I hope to have my own turbocharged Valiant running full-bore (whatever THAT means,) on the drag strip for some first-person information that I can count on (as regards its veracity,) so maybe until that happens, perhaps I should just stop with the turbo-prattle... I think I will.

Thanks for the heads-up! :banghead:

 

[slant6racer]

15 psi

Will

 

[Bill Dedman]

15 psi

Will

Thanks, Will!

That slant 6 made over 484 flywheel horsepower on only 15 pounds of boost. A am assuming (correctly, I hope,) that the motor was on an engine dyno when this graph was produced,..

correct me if I am wrong.

The engines in Tom Wolfe's Dart and Ryan Peterson's cars, which show (on the Wallace online calculator,) to make just over 500 horsepower, were using 18 pounds to do it, not an unreasonable result, for that increase in intake pressure, I think.

But, 484 horsepower for only 15 pounds of boost, is a phenominally-good number IMHO!

I know you shut off early on your 9-second quarter mile run, Will, but how much boost were you running on that pass?

Thanks a lot for the dyno results!

 

[64DartGTinAZ]

My apologies... I try not to be a "fanboy" by backing my contentions up with various and sundry "facts and figures," such as the Wallace website computations and the videos that show the cars I champion, running really fast, but I must do a very poor job of presenting my arguments if my descriptions and performance results come off as "fanboy" prattle...

Keep up the turbo 'boosting', Bill - love reading it - and will get around to following your lead some day...