Dyno day almost here

Builtsn95

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Next week finally to the dyno, my black 97 Cobra vert rebuild will be done. It's been a long road. This upcoming week will be the break in period....mods over the last 9 months are now complete:

- complete top and bottom end rebuild - ported heads, new valves complete, 01 Cobra cams, forged bottom end - Manley flat heads 10:1 compression, refresh Vortech T- Trim
- Mac LT's, Mac O/R x pipe, Magnaflow comp series cat-back
- Pro Force built T-45, Mcleod clutch, MGW lethal shifter
- 18" chrome deep dish bullits, 315 Nitto NT05R's
- Phantom II gauges incl. dash pod

I'm hoping for 600rwhp on 93 octane. Will be tough not to get it on it this week with only the base tune.
 

Builtsn95

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Can't wait to see what you put down. I think you'll hit 600 with that set up. How many lbs of boost are you looking to run?

I was running 12psi before the build....keeping same pulley, with porting, I expect to be in the 9-10 range. Should be making more power with less boost. A pulley swap may be on the horizon.
 

Builtsn95

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Can't wait to see what you put down. I think you'll hit 600 with that set up. How many lbs of boost are you looking to run?

The result are in...EXTREMELY DISAPPOINTING. Put on a Dynojet today by a very reputable tuner - 460 rwhp. It laid over at 6,200 rpm, had nothing left over that. It came up 100rwhp short of what I expected. I can't believe it. boost maxed at 12 psi.

He told me he thought it might be the cams causing this. I also can't believe that the 01 cams would that much of a difference from stock 97 cams.

This car put down at 568 rwhp in 2005 with a very similar setup (except the ported heads).

any advice would be appreciated. The car is actually running well, so my tuner and engine builder are happy. I am not. This should have exceeded previous HP levels.
 

milktasd2

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1. Belt slip?
2. Different dyno. My truck gained 30rwhp just swapping dynos lol.
3. Have you driven it? Does it feel weak?
 

Four Door SVT

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I thought the 97 intake cam was the better of the manufacturer cams, that's what I'm running but some reason I'm wanting to try something else
 

Builtsn95

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1. Belt slip?
2. Different dyno. My truck gained 30rwhp just swapping dynos lol.
3. Have you driven it? Does it feel weak?

It feels strong, running great. Running 12 psi with 3.25" pulley, assuming no belt slip. But 100hp off ?
 

milktasd2

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One dyno reading lower than the other, one dyno set to give out happy numbers, cams degreed off, tires, etc.


The whole nosing off at 6200 is head scratcher to me. Makes me think belt slip, not enough fuel, cams not degrees right, etc.

take all this with a grain of salt. I'm not the smartest.
 

Builtsn95

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Got a dyno sheet?

Yes, I'll put one up tomorrow.

He also recommended installing a MAFIA and heat exchanger (as the car was running relatively hot). I'm wondering if the MAF may be the issue......worth installing and putting back on dyno ?
 

DSG2003Mach1

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I would have figured the tuner would have been logging and looking at your IATS along with commanded vs actual timing

@na svt could probably tell you if the cams are the problem or not
 

ZD302GT

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Do you still have IMRCs on the car? I agree on 12lbs you should be north of 500hp.

If you do still have them get them off of there. They could be causing an artificial restriction causing you to see 12lb but the motor is not actually seeing all of that air. Thus causing it to fall off at high rpm.
 

na svt

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B heads with stock cams, 10:1 compression and 12psi is going to be in the mid to high 400s. If the power is falling off at 6200 it's due to the cams and the boost leveling or dropping off.

Do a compression check, one cylinder on each bank and report back with the results.
 

Builtsn95

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what type of dyno? Why do you not have 96-98 cams?
I was advised to go with the 01 cams....won't mention the shop who did the headwork. ..was told the 01's were more aggressive. God, I hope I don't need to change these.
 

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