Re-testing 318 (dyno) after changes on Tues

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RAMM

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http://www.forabodiesonly.com/mopar/showthread.php?t=340929at

This will be REAL interesting. This Tuesday Mar 15th I get the rare opportunity to dyno test the engine in the above link again. The customer was contacted by the shop rebuilding his transmission and basically broke the news to him that his engine was a mutt and he would be very dissatisfied with it. This caused quite the stink with the shop that built it because now the customer was complaining that they built a weak combo even though the customer chose and purchased many of the components himself! To my amazement the shop did the right thing and contacted me for advice on how to wake it up. Even more amazing is they listened and tore the engine completely down and decked the block .055" and improved compression from a measured 8.1 (lol) to a much better 9.125 static. They also replaced the cam with a Comp 252H and lifters.

The shop is also paying for a dyno session at no additional cost to the owner of the engine. I expect an increase of 25-30 ft/lbs average and more importantly idle vacuum should increase from an abysmal 7-8" to 16-18". Manifold vacuum is such an important characteristic and yet most people and shops pay little attention to it. I will post the results with a review Tues evening. I love doing this kind of testing. J.Rob
 
RAMM said:
http://www.forabodiesonly.com/mopar/showthread.php?t=340929at

This will be REAL interesting. This Tuesday Mar 15th I get the rare opportunity to dyno test the engine in the above link again. The customer was contacted by the shop rebuilding his transmission and basically broke the news to him that his engine was a mutt and he would be very dissatisfied with it. This caused quite the stink with the shop that built it because now the customer was complaining that they built a weak combo even though the customer chose and purchased many of the components himself! To my amazement the shop did the right thing and contacted me for advice on how to wake it up. Even more amazing is they listened and tore the engine completely down and decked the block .055" and improved compression from a measured 8.1 (lol) to a much better 9.125 static. They also replaced the cam with a Comp 252H and lifters.

The shop is also paying for a dyno session at no additional cost to the owner of the engine. I expect an increase of 25-30 ft/lbs average and more importantly idle vacuum should increase from an abysmal 7-8" to 16-18". Manifold vacuum is such an important characteristic and yet most people and shops pay little attention to it. I will post the results with a review Tues evening. I love doing this kind of testing. J.Rob
Click to expand...
That's cool. We will be following along. So many of us have stock teens and would like to improve their performance without breaking the bank or building a maximum horsepower mill.
 
Please, do list the changes to the engine! A before and after list would be great.
 
just read the whole thread on the first try of that 318
interesting to see the results

on a side note, RAMM, what are your credentials in this matter?
do you own/operate the dyno?
how did you end up getting involved?
 
Ok so the testing went well and 4 actual changes were made.

1. Decking the block .055" which raised comp 1 full point. Now @ 9.125 - 1

2. Replace Mopar Perf cam with a Comp 252H (quite a bit smaller)

3. Replace HV oil pump with SV oil pump

4. Test with customers 1 5/8" stainless headers with 3" collector

From the cam breakin to the last pull the engine ran so much better it was hard to believe it was the same engine. Idle vacuum was now at 14-15" @ 750-800 rpm , jetting wasn't touched from the last test session and even though it moved less air through the turbine it still made more power everywhere. I checked cranking compression and new power was going to be good when the gauge revealed 170 psi instead of 135 psi. Oil pressure was a much more reasonable 60-70 psi now. The pretty headers which I am completely impressed with turned all kinds of pretty purples and blues.

The first pull from 3000-5000 was impressive with 347 ft/lbs @ 3000 rpm a full 40 ft/lb gain!
317 hp was showing @ 5000 rpm.

A whopping 6 pulls later we were done with some pretty good results. We pulled it as low as 1900 rpm and 302 ft/lbs was observed.

Years ago I never would have believed such a small cam (206 @ .050" ) would have made anywhere near this kind of power with this tame personality. J.Rob
 

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What were the specs on the cam you replaced?

Running the comp cam simulator, that 256 cam looks MIGHTY good for this type of app, as the tq curve is way flatter than the next up IIRC 262) and only 10 max HP less.
 
This just hammers home that's it's all in the combo. You can preach it till you're blue in the face and some people will not listen. Great job.
 
RAMM said:
Ok so the testing went well all kinds of pretty purples and blues.

Years ago I never would have believed such a small cam (206 @ .050" ) would have made anywhere near this kind of power with this tame personality. J.Rob
Click to expand...

most common mistake seems to be "over camming"

what might be your pick for a stock 340 for all around driving that will not be raced?
 
I should also add here the averages from 3000-5500rpm :

Before After

270.9 hp 296 hp

324.4 ft/lbs 356.7 ft/lbs

.530 BSFC .472 BSFC

25.1 hp gain and 32.3 ft/lb gain average and using less air and less fuel to do it.

Also worth mentioning was the fact that it liked 38 total timing on the 91 octane fuel, I bet it would pick up a couple of points on regular 87 octane, which we ran out of time to do. It's very interesting to look at the fuel and air flow numbers from before and after. J.Rob
 
ir3333 said:
most common mistake seems to be "over camming"

what might be your pick for a stock 340 for all around driving that will not be raced?
Click to expand...

I have used Edelbrock's Performer cam in a 340 which resulted in 330 hp/390 ft/lbs that had a very nice 15-16" vacuum. If you wanted more rumpity rump then I wouldn't be afraid of Comp's 268H or something similar. J.Rob
 
diymirage said:
just read the whole thread on the first try of that 318
interesting to see the results

on a side note, RAMM, what are your credentials in this matter?
do you own/operate the dyno?
how did you end up getting involved?
Click to expand...

Credentials: Certified General Machinist also Certified Motive Power Machinist.
I operate a small machine shop with dyno and flow testing facilities.
Involvement,evolved from just performing the initial dyno testing to "What's the best way to fix this?" The shop that performed the work is very capable and stands behind their work, this was just a case of an ill informed customer that relayed unrealistic parameters upon said shop. Their lines got all crossed up I guess. J.Rob
 
RustyRatRod said:
This just hammers home that's it's all in the combo. You can preach it till you're blue in the face and some people will not listen. Great job.
Click to expand...

It's nice when everyone leaves with a smile on their face to be sure. Thanks RRR, J.Rob
 
RAMM said:
I have used Edelbrock's Performer cam in a 340 which resulted in 330 hp/390 ft/lbs that had a very nice 15-16" vacuum. If you wanted more rumpity rump then I wouldn't be afraid of Comp's 268H or something similar. J.Rob
Click to expand...

now that's going to surprise (educate) a lot of guys!
how about XE256 or XE262?
 
ir3333 said:
now that's going to surprise (educate) a lot of guys!
how about XE256 or XE262?
Click to expand...

I don't care for the XE line of lobes. Decent power production but I won't use them after 2 customers complained about the noise and I had to provide replacements. I also used Comps lifters and when I called them about it they basically told me it was normal. So, no problem I just explored other options, and Lunati has been good to me. J.Rob
 
I have heard this with the larger Extreme Energy cams,but wondered about the smaller models.
..Good to hear an honest opinion..thanks.
 
RAMM said:
I have used Edelbrock's Performer cam in a 340 which resulted in 330 hp/390 ft/lbs that had a very nice 15-16" vacuum. If you wanted more rumpity rump then I wouldn't be afraid of Comp's 268H or something similar. J.Rob
Click to expand...

not to hijack this discussion guys, RAMM. I just rebuilt a 1970 340, 9.5 to 1, roller rockers, springs to match the cam, X heads with hardened exhaust valves, LD 340 intake, 650 thunder series carb,stock HO exhaust manifolds and using a Comp's 268H. What do you think my horsepower and torque be. It is going into a 70 Dart, that is just a cruiser and the odd burnout. I hope to not have problems with the lifters? THANKS FOR THE ANSWER. RAMM
 
RustyRatRod said:
This just hammers home that's it's all in the combo. You can preach it till you're blue in the face and some people will not listen. Great job.
Click to expand...

Bingo!!! You hit the nail on the head Rusty. It doesn't have to sound like a top fueler to make good usable power and torque. Along with that comes enjoyable drivability and even economy. Great combo and thread!
 
RustyRatRod said:
This just hammers home that's it's all in the combo. You can preach it till you're blue in the face and some people will not listen. Great job.
Click to expand...
Yep, I used to take 440's on the street EVERY time with a low duration high lift cam in a 351C; duration at .050" was 192/200 with 114* LSA. That and s static CR in the low 10 range made the torque start early and with good breathing it extended up to over 6000 RPM. It would NOT be the maximal HP combo on the drag strip, but for the street, that is the ticket: moderate cam with as much lift as you can manage with as high a CR that you can manage will start the torque early, and good intake and port and exhaust flows will extend it to high RPM's.

Thanks for sharing, RAMM; very good results there! ANd it is great that you could run a dyno pull starting as low as 1900 RPM; that is what I feel is missing almost all the time with dyno pulls. I would really like to see dyno pulls start at 2000 RPM or 2500 RPM at the most, so that better detail of the low end torque curve can be seen, and comparisons made.
 
...so how would motor home 440's perform in a street car?
They probably had a short duration cam for lots of torque.... should melt the tires in anything with a 323:1 rear gear and pull to 5000rpm...
..what were the stats on the 440 motor home engines?

O.K....just went through IQ52's thread.Great Stuff!
 
nm9stheham said:
I would expect a motor home 440 to have pretty low compression ratio.
Click to expand...

7.5:1,270hp and 400+torque
with headers and an 850 carb hp jumped to 300 and torque 425 ft.lbs
you can find these things for a few hundred dollars.
...i'll bet they would be hard on tires!
 
RAMM said:
I should also add here the averages from 3000-5500rpm :

Before After

270.9 hp 296 hp

324.4 ft/lbs 356.7 ft/lbs

.530 BSFC .472 BSFC

25.1 hp gain and 32.3 ft/lb gain average and using less air and less fuel to do it.

Also worth mentioning was the fact that it liked 38 total timing on the 91 octane fuel, I bet it would pick up a couple of points on regular 87 octane, which we ran out of time to do. It's very interesting to look at the fuel and air flow numbers from before and after. J.Rob
Click to expand...

Nice job Jesse. Sorting out one of these is often more rewarding than building a big inch race engine.
 
IQ52 said:
Nice job Jesse. Sorting out one of these is often more rewarding than building a big inch race engine.
Click to expand...

Thankyou Mr.LaRoy and yes it is pretty rewarding. You should've seen the owner of the shops face when a camshaft with 15 and 22 degrees @ .050" LESS made more power everywhere. He couldn't believe it. I love re-testing engines when significant changes have been made and improvements in efficiency occur. Unfortunately we tend to learn more from failures than success. J.Rob
 
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