Dyno results..

[iwantacobra427]

I got my 331 dynoed yesterday.. 289 rwhp, 272 rwtq. I thought I'd be over 300 on both for sure.. The dyno was a Mustang unit which I heard gives lower results than other dynos. Some info on my engine: Holley 4150 with vac secondaries, RPM Air-Gap, AFR 185, compression ratio ~ 9.5:1, COMP Cam 280HR (mild street/strip), MSD 6AL, mechanical water and fuel pumps, TKO 600, 3.77 diffy.

On a positive note the car is more responsive. I can definitely feel the difference. I gained 21 HP and 15 TQ over the base line due to rejetting and adjusting the timing but it cost $500! What do you guys think?

[Rickd]

I have a 331 stroker built by Keith Craft. Quick Fuel Tec 600 carb, Trick Flow Stage II cam, RPM Air Gap intake, AFR 165 heads, mechanical water & fuel pump, TKO 600 3:54 dif. 326 RWHP at 6000 rpm on a chassis dyno at Mustang Specialties in Fort Lauderdale, FL (not sure if it was a Mustang unit or not). I have Mahle pistons, which I specified after some research I came across showed they were "low friction".

[Power Surge]

Sounds just about right for your motor combo in a Cobra.

My brother used to call my dyno the "dream killer". I'd get Cobra guys with big inch 427s and big stroker Windsors come in and not even break 400 rwhp.

Of course, 9 out of 10 of them needed some serious tune help. A/Fs all out of whack, timing not even close to proper. Funny thing is, people will spend 50 grand or so on the car and not want to spend a few hundred to make it run right (and safe!).

You did the right thing. And think about this.... can you think of any part for your 331 that adds 20 rwhp and only costs $500?

[patrickt]

Originally Posted by iwantacobra427

I got my 331 dynoed yesterday.. 289 rwhp, 272 rwtq. ... What do you guys think?

I think had you gone with a 427 (like you wanted), you would now be basking in the warmth of high HP & TQ numbers. It's OK; in the ERA family we'll just refer to you as "our weak sister."

[iwantacobra427]

Funny! I figure I saved $10k - 20k by going with a FIA. If I went with the 427 model I would of put a 427 SO in it which is big bucks!

[patrickt]

Originally Posted by iwantacobra427

Funny! I figure I saved $10k - 20k by going with a FIA. If I went with the 427 model I would of put a 427 SO in it which is big bucks!

Spoken like a true weak sister.

[Rickd]

I went with an FIA because - to me - it is the best looking cobra period to ever prowl the roads - and the one the Shelby team actually raced to win the Manufacturer's World Championship. The ERA427 and FIA cost the same - and a Roush 427 (stroked 31) wouldn't have cost much more than my fantastic KC 331 Stroker.

[patrickt]

Originally Posted by Rickd

... and a Roush 427 (stroked 31) wouldn't have cost much more than my fantastic KC 331 Stroker.

Calling a Roush a "427" in the same breath as the word "Cobra" is an exercise in deception.

[diegokid]

iwantacobra427

Don't feel bad, I have a SA 406 FE that only made 270 RWHP as delivered.

[767Jockey]

Originally Posted by diegokid

iwantacobra427

Don't feel bad, I have a SA 406 FE that only made 270 RWHP as delivered.

Hmmmmmm.......what did the folks at SA have to say about that?

[patrickt]

Originally Posted by 767Jockey

Hmmmmmm.......what did the folks at SA have to say about that?

"Should of bought a Roush."

[Power Surge]

Originally Posted by patrickt

"Should of bought a Roush."

Trust me, Roush isn't much better. I've dynoed plenty of Roush motored Cobras that were WAY down on power from what they were "advertised" at.

[patrickt]

Originally Posted by Power Surge

Trust me, Roush isn't much better. I've dynoed plenty of Roush motored Cobras that were WAY down on power from what they were "advertised" at.

All of the advertised HP numbers on engines are fake -- it's just like advertised prices on cars. Most of the better known engine builders will tell you the truth though if you ask them "With everything hooked up on the engine, and with the mufflers attached, what will it make at the crank?" and then follow it up with "... and what does that usually translate to in HP at the rear wheels with my trans. and the POS rear I'm using?" You know they know the answers.

[Power Surge]

Originally Posted by patrickt

All of the advertised HP numbers on engines are fake -- it's just like advertised prices on cars. Most of the better known engine builders will tell you the truth though if you ask them "With everything hooked up on the engine, and with the mufflers attached, what will it make at the crank?" and then follow it up with "... and what does that usually translate to in HP at the rear wheels with my trans. and the POS rear I'm using?" You know they know the answers.

I think the problem is companies like Roush build one motor, setup perfect on their dyno, with proper exhaust, etc, etc and then use those dyno numbers to advertise the motors. In theory, they SHOULD all make the same power, but of course they don't. And then we put them into Cobras with their horrible power robbing side pipes and hp eating IRS setups and wonder why the car makes 200 hp less, LOL.

[Got the Bug]

Originally Posted by patrickt

All of the advertised HP numbers on engines are fake -- it's just like advertised prices on cars. Most of the better known engine builders will tell you the truth though if you ask them "With everything hooked up on the engine, and with the mufflers attached, what will it make at the crank?" and then follow it up with "... and what does that usually translate to in HP at the rear wheels with my trans. and the POS rear I'm using?" You know they know the answers.

So the Dyno results that Roush provided me with my engine are not actual results at the crank? Same thing with a KC engine or a Ford Crate Motor?

Never been on a Dyno to see what the readings are at the rear wheels. Don't really care.

[patrickt]

Originally Posted by Got the Bug

So the Dyno results that Roush provided me with my engine are not actual results? Same thing with a KC engine or a Ford Crate Motor?

Never been on a Dyno to see what the readings are at the rear wheels. Don't really care.

To a certain extent, yes. Especially if they dyno'd you with open pipes, even more so if the water pump was not running, extra even more so if they dialed in a "compensation factor," etc. The only true numbers that you can believe are the ones you see with your own eyes on a chassis dyno.

[Got the Bug]

Originally Posted by patrickt

To a certain extent, yes. Especially if they dyno'd you with open pipes, even more so if the water pump was not running, extra even more so if they dialed in a "compensation factor," etc. The only true numbers that you can believe are the ones you see with your own eyes on a chassis dyno.

Makes sense. Thanks for the clarification.

[patrickt]

Originally Posted by Got the Bug

Makes sense. Thanks for the clarification.

... and that's "industry-acceptable" fudging. For some of the other stuff, check this out: http://www.turbomagazine.com/tech/04...ems/index.html

[DAVID GAGNARD]

Originally Posted by iwantacobra427

I got my 331 dynoed yesterday.. 289 rwhp, 272 rwtq. I thought I'd be over 300 on both for sure.. The dyno was a Mustang unit which I heard gives lower results than other dynos. Some info on my engine: Holley 4150 with vac secondaries, RPM Air-Gap, AFR 185, compression ratio ~ 9.5:1, COMP Cam 280HR (mild street/strip), MSD 6AL, mechanical water and fuel pumps, TKO 600, 3.77 diffy.

On a positive note the car is more responsive. I can definitely feel the difference. I gained 21 HP and 15 TQ over the base line due to rejetting and adjusting the timing but it cost $500! What do you guys think?

Depending on your sidepipes and a few other things, using a 20% driveline loss, that would come out to around 360 hp at the crank....I think that would be about right for your combo.........

David

[iwantacobra427]

Originally Posted by patrickt

Spoken like a true weak sister.

was about engine size. I told him I was planning on a 331 which he said was a good choice. He said "don't make the mistake of trying to compensate for lack of size in another area like some 427 Cobra guys".