How much power do engine mods yield?

-
slant6racer said:
That is at the wheels Bill!!!
15 psi on that pass. (14.95 actually)
Will
Click to expand...

Wow! WOW!!!![/If you use the "85%" time-honored rate that everyone seems to believe, for converting rear-wheel horsepower to flywheel numbers, then that means that this 225 slant six was actually putting out 570 FLYWHEEL horsepower (my calculator says that 570 times 85% is 484.5.) on ONLY 15 pounds of boost!

That, my friends, is just amazing!!!

I can't IMAGINE what it might do, if the boost level were raised to, say, 25 pounds!

Will, are there any plans for another dyno-test, or another assault on the quarter-mile at increased boost levels? I know you shut down early on the one 9-second pass you made. Sounds like if you increased the boost to, say, 25 pounds, and stayed on the throttle all the way to the finish-line, some incredibly-fast numbers could be posted!

Curious minds want to know... :blob:

And, thanks again for the explanation.... it's a mind-blower...
 
64DartGTinAZ said:
Keep up the turbo 'boosting', Bill - love reading it - and will get around to following your lead some day... :)
Click to expand...

Thanks for the support and encouragment. The facts surrounding turbocharged slant sixes are not very much in evidence within the Mopar community... it's just a too-well-kept secret.

To me, it seems that there are two avenues of approach to this exercise: Depending on how much money you have to spend on this upgrade, you can either, use stock internals (cast pistons, stock rods and no O-Rings) and build a low cost, low boost engine that will push a typical A-Body to low-14's/high 13's (quarter-mile times) and be a pump-gas motor, or, if you have more money to spend, opt for the forged-internals motor (Wiseco Pistons/K-1 rods and O-Rings,) and shoot for horsepower in the 400+ range. That motor will probably get your A-Body a low 11-second, or high-10 second timeslip. But, it stops being a pump-gas motor somewhere north of 250 horsepower, I think; an important consideration.

You pays your money and you takes your choice! :cheers:

At any rate, either combination is a viable alternative to swapping in a V-8, I think.:coffee2:
 
Yes, we will be back with a new sheet metal intake and a flat hood. With the new intake I think I have a lot left at 15 psi (better air distribution). It has been a very busy year and the race car has been on the back burner, but we are getting back on track this fall (I hope).
Will
 
slant6racer said:
Yes, we will be back with a new sheet metal intake and a flat hood. With the new intake I think I have a lot left at 15 psi (better air distribution). It has been a very busy year and the race car has been on the back burner, but we are getting back on track this fall (I hope).
Will
Click to expand...

Will,

I still can't get over the fact that you are making all that (considerble) power with ONLY 15 pounds of boost!

I only have a carburetor on my motor; fuel injection is a little out of my "frame of referencce".... I'll probably never have the smarts to try anything but a Holley 4bbl. But, you are obviously on the right track! I have been told (by sources whose opinion, I respect, highly,) that the long-runner Aussiespeed intake manifold I m using is killing my motor. I bought it before they had a short-runner for sale, and can't seem to work up the enthusiasm necessary for spending another $500+ for the short one... What do you think?

Please keep us informed about your progress. There's nothing in this whole country, anything like your car!:cheers:
 
Bill Dedman said:
Will,

I still can't get over the fact that you are making all that (considerble) power with ONLY 15 pounds of boost!
There's nothing in this whole country, anything like your car!:cheers:[/QThe numbers don't lie: If the engine is .045" overbored, ir has

So, the engine is 231 cubic inches, and makes 570 flywheel horsepower. That's 2.48 horspower per cubic inch!

If a 408 (stroker 360) made that much power, it would be putting out 932 horsepower!

Probably blow the crank right out on the ground... LOL!

And, rermember folks, that is on ONLY 15 pounds of boost; more to come!!!!


You go, guy! :cheers:
Click to expand...
 
Lahti35 said:
Thanks for all the info guys! Torque is indeed what I am after...

The car will be used mostly as a commuter on 55mph roads with city driving making up 50% of the trip. Previously I used a 1961 Falcon as my commuter but that 144 inline was a dog... really got tired of people thinking I was an old fart poking along and cutting me off!

Interesting comment on keeping the auto tranny... would not have guessed that.
Click to expand...

I always wondered about the rationale of drivers who aggressively cut me off to not be behind my 45 year old Valiant...cuz now they're in front of my 45 year old brakes...
 
kesteb said:
The same logic that leads them to cut off 80,000 lbs semi's.
Click to expand...

The original poster of this thread asked about the viability of add-on hop up hardware such as increased carburetion, compression, exhaust capability and camshaft chacteristics as regards how effective they would be in a naturally-aspirated street engine. This discussion has, as online discussion threads are prone to do, drifted far afield of that, and, I am probably one of ther worst offenders when it comes to hijacking threads, with all my turbo-this and turbo-that prattle.

I would like to take this opportunity to apologize to the O.P. for that. It's probably VERY frustrating to ask a question and, in just a few posts, read the answers to a whole bevy of questions you DIDN'T ask, while NOT getting the answers to the ones you DID ask.... In his original post, he asked:

"I pulled this posting from the forum and was wondering how much extra power you're going to get with mods like this...


See if he will recurve the distributor for you too. That is a low cost high gain improvement.
I would do this in this order:
Cam and head work (dutra cam/shaved head)
Distributor recurve

2 bbl Supersix with the next $200-$300 you can invest.
Better throttle response and better pull up through the rpm's

Dual exhaust with the next $500-$600
Better mid to high rpm power

Is it a noticeable difference or just a slight bump up. My car is going to be a '65 Valiant 2 door and I'm wondering how much of a difference these mods would make along with adding a manual trans and better rear end gears...

I don't want to swap the engine, I really dig the slant 6!"

Let's start over and see if we can give him some answers to these questions:

I'll start...

To begin, the headwork is critically-important on a naturally-aspirated engine, but is unduly expensive because it's a cast iron head and has long ports that have places that are hard to get the grinder to. Bost is Uuusally in the neighborhood of $1,200.00-$1,400.00 for a profesiional job. But, the OEM valves and ports are restrictive on the stock head; it's pretty much a necessity if you are ever going to make a significant improvement in the engine's output. The additional, add-on parts like manifolds (both intake and exhaust,) will be seriously hamstrung if you try to make those improvements with a stock head.I think a 500cfm two bbl carb on a Super Six manifold would flow suffucuent air/fuel to feed a 225 that was redlined at 5,500 rpm, a reasonable redline with moderate aspirations (225 horsepower.) That's one horsepower per cubic inch... not anything to scoff at... The 2bbl setup should be reasonable in terms of money-spent...

I'll leave the rest of the mechanical parameters to someone more knowledgable than me... shouldn't be too hard to find dozens of guys like that , here,(and, probably, a few girls. too!)
 
There is an engine build matrix on slantsix.org. Pick one and follow it. They are proven recipes.

A quick and dirty recipe would be a stock 225 with a Supersix manifold, Autolite 2100 1.08 carb with #48 jets, recurved distributor with initial at 15* btdc, 30* total, all in before 3000rpm. A 2 1/2" exhaust from the stock manifold to the bumper. A TransGo shift kit in the transmission.

The 2 biggest improvements were the exhaust and the shift kit. This combo drop 2 seconds off a '73 Duster.
 
kesteb said:
There is an engine build matrix on slantsix.org. Pick one and follow it. They are proven recipes.

A quick and dirty recipe would be a stock 225 with a Supersix manifold, Autolite 2100 1.08 carb with #48 jets, recurved distributor with initial at 15* btdc, 30* total, all in before 3000rpm. A 2 1/2" exhaust from the stock manifold to the bumper. A TransGo shift kit in the transmission.

The 2 biggest improvements were the exhaust and the shift kit. This combo drop 2 seconds off a '73 Duster.
Click to expand...

Kesteb,

Thanks for that information. That is exactly the kind of plan I think the O.P. was looking for.

Back in 1963, we took a 225 slant six that was nearly new, in a 1962 Dodge Lancer and installed a Hyper Pak 4bbl intake manifold and carb, milled the head .100, and installed the Hyper Pak cam and a 3.55:1 rear gear (with Atlas Bucron tires,) but no header; the header wouldn't fit... It hit the starter solenoid, so we left the stock (tiny) exhaust on it... but, removed the muffler...

It ran 15.88 @ 89 mph. Beat a lot of V8s with that car... It had a 904 with a stock torque converter.
 
You must log in or register to reply here.
-

Back
Top