635HP at 20# on E85 seems low, Ideas?

04OWwhipple

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My stock engine/ECU combo with whipple 2.9 with a 3.25 upper and stock lower made 708 to the tire. I cracked the stock engine block and had to get the short block rebuilt. I had a used short block machined and assembled using factory crank with oliver rods and MMR pistons with a slight compression bump to 9.2 or 9.3:1 and total seal file fit rings. Also had the heads rebuilt and surfaced at the same time. I put the heads on the short block and assembled the rest of the long block myself. It runs well and I'm working on smoothing out the tune for low load right now but WOT is dialed.

We strapped it on the Dyno yesterday and with that same 3.25 pulley on E85 it was only making 635 to the tire. I expected it to make just as much as before if not slightly more with the bump in compression. Then with a 150 shot of spray it only picked up about 80HP and made 716.

I fear something may be amiss in the bottom end. I did not assemble that myself and now I am worried. Any good ideas to start with? I'm gonna do a compression test when I can get to it here soon.
 

04OWwhipple

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you absolutely need to do a compression test because something is definitely wrong there.
Same exact dyno and tuner?


Same Dyno, but different tuner. The previous stock engine setup was tuned by HPP Racing in Texas using the Stock ECU and a SCT piggyback chip. I'm leaning away from the tune as we played with timing to see what it liked and it peaked at only 635HP and AFR is good so I dont think it's in the tune at the moment but I could be wrong.

The engine rebuilder missed all the crack in my original block and after putting it back in the car, I was still losing coolant. So I took it back out and disassembled and found the cracks he had missed. Now I'm wondering if he didn't mess something up with the 2nd short block rebuild.
 

GNBRETT

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Dyno's can vary quite a bit from day to day with temps. Was it the same dyno and same temps as before? I wouldn't get too wrapped up with the dyno thing. Take it to the track or take it out on the street with a G-meter and see what the trap speed is.

Could be valve float issues or some detonation from too much timing. Clutch maybe starting to slip as well. Are u sure the timing is being pulled back when the N20 is hitting?

N2o can also spike TQ to go way up causing a leaning condition so it gets richer and richer as u put more power to it causing hp to drop.

Im betting its ur tune with ur N2o this is ur culprit.
 

BlckBox04

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I know that dyno's can vary, but with the exact same pully combo and better fuel, a 73 hp difference doesn't seem really off to anyone?
I'm excluding the nitrous issues because that's an animal all in itself
 

04OWwhipple

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How does it run? What does it trap? Maybe low reading dyno?

I feel like it runs pretty smoothly so I don't think it's massive screwed up but it seems like super low power. It traps 132-135 on spray. Had one freak pass at at 139MPH but most of them are 132-133s with 1.8 60 foots.

what is the full setup? ow much boost?

4.6 iron block bored .020 over
MMR pistons for 9.2-9.3:1 compression
.002 cleaning cut off of heads
Stock heads rebuilt with bronze valve guides, no porting
Stock cams and valve springs
Kooks long tubes w/ bassani exhaust
2.9 Gen 2 whipple w/std inlet and 3.25 pulley

It makes right about 20-21 PSI depending upon air temp
Timing peaks at 21*
 

04OWwhipple

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Dyno's can vary quite a bit from day to day with temps. Was it the same dyno and same temps as before? I wouldn't get too wrapped up with the dyno thing. Take it to the track or take it out on the street with a G-meter and see what the trap speed is.

Could be valve float issues or some detonation from too much timing. Clutch maybe starting to slip as well. Are u sure the timing is being pulled back when the N20 is hitting?

N2o can also spike TQ to go way up causing a leaning condition so it gets richer and richer as u put more power to it causing hp to drop.

Im betting its ur tune with ur N2o this is ur culprit.

Same dyno but different day so temps were different. on boost only, being 70 HP down with the same pulley on a fresh engine just doesn't line up to me. That is on boost only. The fact that the nitrous is putting me back to the power I was on the old engine on boost only is alarming to me.

Pulling 4-5 degrees timing with solid AFR's during logs when spraying so that is where it should be too. right at 11.5 AFR when spraying
 

04OWwhipple

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if you're trapping 132-134 then you're make that power level

I completely agree. I was trapping 132-134 on my old engine with just boost only. and now I'm running the same MPH but spraying. All with a fresh engine makes me think something is quite a bit off.
 

BlckBox04

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I completely agree. I was trapping 132-134 on my old engine with just boost only. and now I'm running the same MPH but spraying. All with a fresh engine makes me think something is quite a bit off.

I made 640 bone stock engine, no juice whipple 2.9 standard inlet and I'm trapping 134
 

c6zhombre

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There's no way that's right.....park the car, get the compression test done.

"MMR pistons 9.2-9.3 compression" - I would want to double and triple check those out....make darn sure they're what they're reported as being.
 

01yellercobra

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Until you do a compression or leak down test we're all just guessing. Start and the bottom and work your way up.
 

BlckBox04

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There's no way that's right.....park the car, get the compression test done.

"MMR pistons 9.2-9.3 compression" - I would want to double and triple check those out....make darn sure they're what they're reported as being.

dude I totally didn't even realize what he said, MMR.... that would be the first indication of a catastrophe.
 

04OWwhipple

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I made 640 bone stock engine, no juice whipple 2.9 standard inlet and I'm trapping 134

I may be a poor driver then. Either way it seems to be trapping the same as before when I didnt have spray.

There's no way that's right.....park the car, get the compression test done.

"MMR pistons 9.2-9.3 compression" - I would want to double and triple check those out....make darn sure they're what they're reported as being.

I'm gonna try to get to it this week. I'm moving here pretty soon so I have a lot on my plate coming up time wise.

Do a lot of people have wrong compression pistons form them?
 

decipha

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you basically have a stock engine w/ long tubes a 2.9 whipple on 20psi and e85

660rwhp and 830rwhp on a 150 shot is the norm for your setup.

if its a new engine that hasnt been broken in yet then its common to have lower numbers

have yall tried pulling some timing out? I wouldnt be surprised if it made more power with less timing.
 

04OWwhipple

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you basically have a stock engine w/ long tubes a 2.9 whipple on 20psi and e85

660rwhp and 830rwhp on a 150 shot is the norm for your setup.

if its a new engine that hasnt been broken in yet then its common to have lower numbers

have yall tried pulling some timing out? I wouldnt be surprised if it made more power with less timing.

Essentially yes it is pretty much a stock engine combo. It is relatively new but has been broken in, it probably has 500-700 miles or so on the new engine which would make me think everything has seated by now.

We did pull a little bit of timing on the top end. On boost only, it is right around 21* from 3000-5500, then it ramps outs to 16-17* from 5500-7000 RPM. It made the same power on that timing curve compared to just holding 21* to redline.
 

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