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Yeah to use meth on E85.. I will be over 20lbs of boost with 10.5 compression.
I am kinda scared E85 may not be enough honestly?
I'm 10.6 to 1 with 20 psi I can run 50% ethanol and no meth with no issues. I only added the meth to experiment with it and then fell in love with the benefits. You will not get over 20 psi on that motor with the F1a. I'm only a 377 with stock heads spinning an F1a-94 to max recommended impeller speed hitting 20 psi. These can safely be spun higher and probably gain a little more, but with that motor you have it's going to be more efficient than my little motor with crap heads so you will not get over 20 psi out of that blower on that combo.
Like mentioned it's the tune not the boost level. Too much timing for the combo and yes you will have issues.
I don't mean to worry the OP, but I have a very similar setup and...
Originally Posted by The ******
Should make about 500whp.....
That's actually pretty close to what I got with a similar setup 540 rwhp SAE on 13 psi through a T56.
402ci, 10.5 CR
Ported 243's
Brute Speed Blower Cam 232/240 with low .600 lift
E85 with 18* of timing
~11.0 AFR
F1A spinning 65k RPM - about 13 psi boost
540 rwhp.
A forged 5.7 engine with same Procharge setup prior to this made 530 rwhp.
The forged 402 with AFR heads prior to that made 580 rwhp on 13 psi as well.
I've got about $10,000 into diagnostics over 3 engines and 8+ years. I've taken it to a few shops and no one has been able to figure it out. I have hundreds of hours into figuring this out. Nothing I've done has made any substantial improvement. I hope you're luckier than I.
I don't mean to worry the OP, but I have a very similar setup and...
That's actually pretty close to what I got with a similar setup 540 rwhp SAE on 13 psi through a T56.
402ci, 10.5 CR
Ported 243's
Brute Speed Blower Cam 232/240 with low .600 lift
E85 with 18* of timing
~11.0 AFR
F1A spinning 65k RPM - about 13 psi boost
540 rwhp.
A forged 5.7 engine with same Procharge setup prior to this made 530 rwhp.
The forged 402 with AFR heads prior to that made 580 rwhp on 13 psi as well.
I've got about $10,000 into diagnostics over 3 engines and 8+ years. I've taken it to a few shops and no one has been able to figure it out. I have hundreds of hours into figuring this out. Nothing I've done has made any substantial improvement. I hope you're luckier than I.
I'm gonna go out on a limb here and say something is amiss....
My previous SBE LS1 car with ported 317's, mystery turbo cam and old *** cast wheel 7875 turbo made 700whp on rams' **** pump gas only at 14 lbs. through a T56.
You should be winding that thing out to 6,500-7,00rpm, you need to figure out why power is falling off so soon.
Bad valve springs, cam degreed incorrectly, something is off.
Not trying to hijack OP's thread, but I hope this is sorta relevant given our combinations are similar and it keeps the discussion going.
Originally Posted by The ******
I'm gonna go out on a limb here and say something is amiss....
My previous SBE LS1 car with ported 317's, mystery turbo cam and old *** cast wheel 7875 turbo made 700whp on rams' **** pump gas only at 14 lbs. through a T56.
You should be winding that thing out to 6,500-7,00rpm, you need to figure out why power is falling off so soon.
Bad valve springs, cam degreed incorrectly, something is off.
Yeah, it's frustrating talking with people who are like, "I have a $700 junkyard engine and a $200 turbo off a diesel truck and I made 650 rwhp, wtf is wrong with you", lol.
Oh, I do wind it out to 7k, the dyno operator actually stopped the pulls short because he was so alarmed at the lack of power.
Cam has been degreed twice by me and once by a pro - within 1-2* of expected valve events.
I thought something was wrong with my last engine (forged LS6) with 2000 miles, so I took it out and scrapped it, built this 2nd 402 and have the same issue. I've swapped 4 sets of different coil packs on with 2 sets of different wires. I've tried stock plugs at 0.030 and NGK plugs everywhere from 0.040 to 0.010 with no change.
This is the 3rd set of heads on the various engines, all with 0.650" or higher rated springs (BTR platinum and AFR 8019's).
All cylnders are 180-190 psi cranking pressure. All leakdown's within 10%.
The only theory I or others can come up with is that the ECU is just selectively mis-firing cylinders above 5000 RPM, but there's not been a good way to prove that (I don't have any misfire codes). I got some high speed data acquisition on my crank trigger wheel and wrote some code to process it during a pull and see if I could measure slow down's in the instantaneous crankshaft velocity during certain strokes, but with only 500 kHz acquisition rate, there was still too much uncertainty in the timing of the rising edge's to really see anything. I think I'd need a 2Mhz data acquisition system for that.
I just recently bought a $1500 EGT measurement system and welded in bungs in every header primary to see if I notice any issues in EGT, but this will only tell me if I have a dead hole. If the misfires are random, there will be no way to tell is my guess.
I guess I've just learned that there's no guarantee that putting go-fast parts on will actually make you go faster and there's not always someway to figure it out with reasonable amounts of time or money. Sorry, this has turned more Debbie Downer than I'd have liked. I just like to see threads of people with F1A's who actually make power and live vicariously through them! If OP gets anything over 700, I'd call that a win.
A procharger is never going to make max power at 5500 rpm in an LS of any size. Ok never say never...lol. It doesn't matter how high you are spinning the motor your max power is at 5500 rpm and falling off. You should make 500+ rwhp with a 402 naturally aspirated with a manual transmission. Something is definitely wrong. Sorry I don't know what.
The OP not replying with results is a little concerning though.
Got some OG GTO guys in here... FSAE, have you dynoed the engine without the belt on to see what it does NA? I agree with BCNUL8R the power peak should be at peak RPM. You say you are spinning the headunit to 65k, what engine RPM is that at? Also, what bypass valve are you running as some of them start to leak with higher boost levels. Last, what intake are you running and was it the same one on both engines? The OP seems to have gone AWOL so we might as well try to help.
Got some OG GTO guys in here... FSAE, have you dynoed the engine without the belt on to see what it does NA? I agree with BCNUL8R the power peak should be at peak RPM. You say you are spinning the headunit to 65k, what engine RPM is that at? Also, what bypass valve are you running as some of them start to leak with higher boost levels. Last, what intake are you running and was it the same one on both engines? The OP seems to have gone AWOL so we might as well try to help.
Ha, yeah it has been a long time. I've kept the GTO all this time, but life gets busy, and the car has spent so much time not running or troubleshooting, it's been hard to keep actively posting. Finally have the money/time/space to put towards getting this car where it should be.
I think my 65k RPM number was low - these pulls were with a 7.65" crank, 4.00" PC pulley. So, 6900 RPM shift point is 71k RPM (out of 74k RPM max)
I am running the procharger Big Red race valve. I too thought it might be leaking, so I put a rebuild kit in it 2 years back, but it didn't really affect boost pressure.
The entire induction system from procharger to IC to stock LS2 manifold has been the same across 4 engine combinations. Even the procharger pulley combination has been the same.
2009 - 760 rwhp 402 (previous owner - builds new 402 due to blowby issue)
2010 - 600 rwhp 402 (previous owner - sold to me because he couldn't figure out why it was so low on power with new engine)
2011 - 0 rwhp - motor lets go right after I buy (for uncertain reasons - maybe clogged injector running lean)
2015 - 550 rhwp 347
2020 - 550 rwhp 402
I have only done 'street dyno' pulls with some post processing to turn acceleration into rear wheel torque (and do the SAE correction as well). I've compared this method with a superflow chassis dyno in the past and it was within 10 ft-lbs through the RPM range. Here's a plot showing a few points from the Dynocom chassis dyno plot above, a 4th gear 'street dyno' pull just to see how it compares, and a pull with this motor NA back in 2018 (ignore the waviness, I had a lot of data points from HPT in that log, so the normal smoothing I apply didn't smooth it enough). You can clearly see that the procharger makes the expected torque increase up to about 5000 RPM, then instead of more boost adding more boosted torque, I actually lose the torque gain vs. NA. By they time I get out to 7k RPM's with ~14 psi, torque is nearly equal to NA torque...
Obviously, the NA engine by itself is sorta sad for a 402 ci motor - it is basically right at 400/400. I had a 6.0 in my original GTO that made 430 rwhp with nearly the same cam. I got lazy (and cheap) with this engine and figured I didn't need aftermarket heads right away - partly because I figured the boost would just make power regardless. I also naively just sort of assumed 10% more displacement would equal 10% more power. Instead, I've realized that the heads really control airflow, and if you just increase displacement on the same heads and change nothing else, you'll just move the torque earlier in the powerband, but peak power won't really be improved. So, from that point of view, if I use my old 6.0 as a reference, I guess it actually makes sense that this 402 makes less power. I've lost a ported LS2 intake (10+hp), Stepped headers for single diameter (5-10hp), underdrive pulley (5-10hp), ~1 point of compression (10-15 hp).
This said, even if the NA engine power might sort of makes sense, not one person I've talked to is comfortable saying the NA engine is 'good'. 402's don't just make <400 lb-ft peak torque. So, as a troubleshooting step, I have taken the procharger off, swapped the pseudo stock 243's out for a set of older AFR 225 heads and bought a FAST 102 to replace the stock intake manifold. I would like to see 480 rwhp with this NA combination because that's at least in the realm of what you'd expect a 402 to be able to make and should then give a better baseline for the boosted output. Unfortunately, this swap has introduced a weird lifter tick and idle AFR difference bank to bank, so I've gotta go figure this out before I can attempt to troubleshoot boosted power
OK, get rid of that LS2 intake manifold today, they leak internally and flow awful making for a huge power loss, the FAST 102/225's will go a long way. Something in the NA combo is choking flow bad and I think once that is sorted you will be into the 800's. Did you get the correct length pushrods with the new heads? Also, what intercooler and piping do you run? A bigger IC than the procharger one is helpful and you need to get rid of some of the huge reductions in pipe diameter if you haven't already done so. Get the NA combo pulling cleanly to 7000 RPM making 470ish and you will be happy with the procharged combo.
06-15-2024, 02:35 AM
