Dyno results..

iwantacobra427 · #1 (**permalink**) 07-26-2009, 09:31 AM

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 · #2 (**permalink**) 07-26-2009, 09:43 AM

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 · #3 (**permalink**) 07-26-2009, 09:44 AM

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 · #4 (**permalink**) 07-26-2009, 09:45 AM

Quote:

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 · #5 (**permalink**) 07-26-2009, 10:44 AM

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 · #6 (**permalink**) 07-26-2009, 10:51 AM

Quote:

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.

iwantacobra427 · #7 (**permalink**) 07-28-2009, 06:26 PM

Quote:

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".

patrickt · #8 (**permalink**) 07-28-2009, 06:28 PM

Quote:

Originally Posted by iwantacobra427

... "don't make the mistake of trying to compensate for lack of size in another area like some 427 Cobra guys".

Some; not all.

Rickd · #9 (**permalink**) 07-26-2009, 12:12 PM

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 · #10 (**permalink**) 07-26-2009, 12:20 PM

Quote:

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 · #11 (**permalink**) 07-26-2009, 01:37 PM

iwantacobra427

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

767Jockey · #12 (**permalink**) 07-26-2009, 02:26 PM

Quote:

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 · #13 (**permalink**) 07-26-2009, 02:28 PM

Quote:

Originally Posted by 767Jockey

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

"Should of bought a Roush."

DAVID GAGNARD · #14 (**permalink**) 07-26-2009, 06:08 PM

Quote:

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

Got the Bug · #15 (**permalink**) 07-28-2009, 07:21 PM

Quote:

Originally Posted by DAVID GAGNARD

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

So 20% to 25% is a good rule of thumb to calculate the loss from the crank to the rear wheels?

I guess I don't need a dyno to tell me I have enough oomph! The dyno tag on my Roush 402SR/TW came back at 486 HP and 496 Torque at the crank. Less 20% and I've still got more than I need for street use.

Power Surge · #16 (**permalink**) 07-28-2009, 07:41 PM

Quote:

Originally Posted by Got the Bug

So 20% to 25% is a good rule of thumb to calculate the loss from the crank to the rear wheels?

I guess I don't need a dyno to tell me I have enough oomph! The dyno tag on my Roush 402SR/TW came back at 486 HP and 496 Torque at the crank. Less 20% and I've still got more than I need for street use.

In my experiance dynoing Cobras, that's a pretty valid loss figure.

Also, so many people get caught up on dyno numbers, because they spent big bucks for more motor than they really need because they paid for big power numbers. The reality is the cars are plenty fast regardless of what numbers show compared to what they expected.

My FE powered CSX makes 320 rwhp and is FAR from "slow".

patrickt · #17 (**permalink**) 07-28-2009, 07:55 PM

Quote:

Originally Posted by Got the Bug

The dyno tag on my Roush 402SR/TW came back at 486 HP and 496 Torque at the crank. Less 20% and I've still got more than I need for street use.

Lop off 85 horses for the pipes, 20% drive train loss, and you're down at PowerSurge's rear wheel numbers.

Got the Bug · #18 (**permalink**) 07-28-2009, 07:57 PM

Quote:

Originally Posted by patrickt

Lop off 85 horses for the pipes, 20% drive train loss, and you're down at PowerSurge's rear wheel numbers.

Still enough. Where you at?

patrickt · #19 (**permalink**) 07-28-2009, 08:01 PM

Quote:

Originally Posted by Got the Bug

Still enough. Where you at?

440hp at the crank, with pipes attached. Probably 350hp at the rear wheels.

DAVID GAGNARD · #20 (**permalink**) 07-28-2009, 07:56 PM

Quote:

Originally Posted by Got the Bug

So 20% to 25% is a good rule of thumb to calculate the loss from the crank to the rear wheels?

I guess I don't need a dyno to tell me I have enough oomph! The dyno tag on my Roush 402SR/TW came back at 486 HP and 496 Torque at the crank. Less 20% and I've still got more than I need for street use.

Zacctly, you've got plenty of power and can probably blow away 95% of the vehicles you'll encounter on the street!!!!!!!!!!!!!!!!!

I've got about 325 to 350 hp at the crank in my tired 351-W in a 3100 pound 65 Fastback and the good thing is I can put it all to the rear wheels pretty much at will and not blow the tires off it... From 0 to 100 mph it is pretty darn quick and at the drag strip I've beat a lot of cars with 100hp more than I have. Being able to effectively use the hp you have is as important as having the hp in the first place.....600 hp will not make a car any faster if it can't hook it up and put the power to the rear wheels....

David