So for the winter I normally put the car back on 92 octane to ease starting and reduce the temptation to look for fights since the air is cold and it generally rains non stop here for 5 months. Today was one of those rare days where the air was a little warmer and the ground was dry. I had been meaning to go back to the dyno to see what the car did at high boost on 92 anyway and today was it.

I wont get into the build specifics since that can be found in my build thread link but the main change tonight was 92 octane and boost to match. AFR was dialed at 11.9 and I just kept raising the boost until it seemed about right. Anyone following my how to tune an 800whp car will notice that this one had an added twist. No knock, but the knock voltage was pegged past 7k. We have tuned cars this way before, I had good ignition maps from other cars with this boost level on 92, but still it shows sometimes just numbers alone dont or wont get you the tune you want. Looking past the data sometimes is what it takes. That and a plug chop and read, det cans, etc. but I digress-





Not sure if this is a record, thats not the intent, but I do think it would be interesting to talk about high horsepower pumpgas motors in this thread. Dave if you wanna talk about the crazy cars you pump out, we know your dyno seems to average around 13% lower than ours so what do you see on the crazy builds?

aaron

 

Sweet I want that power on pump.

 

nice works guys

 

Great work as always Aaron.

 

I don't understand how knock voltage can increase while knock sum decreases. I thought one was a function of another.

She's not even hitting 30 PSI and making this. Nuts!

 

It's been a while since I read JCSBanks thread, so the details could be missing. Knock sum is based on the knock voltage peaks going above a moving average of the knock voltage. You get knock counts when the peak goes above a certain threshold above the average knock sensor level.

If the moving average gets high, because of either a noisy motor, sustained detonation, or just loud combustion, you can easily max out the moving average value to the point where the knock sensor cannot put out a signal high enough to trigger the knock sum counter.

This can happen on pumpgas pretty easily, as from what I have noticed, as you drop the ignition advance it makes the combustion event more noisy and the average knock sensor voltage will climb. The same thing happens with RPM, the higher the revs, the higher the average knock voltage level.

Knock sensors work for the typical 400HP build. They are pretty reliable down at the lower RPM ranges too (below 6000 RPM, IMO). But once you start pushing a setup hard on boost or RPM, I would never rely on the knock sensor. Also, built motors can negate all this, as I've seen numerous that manage to max out the average knock voltage pretty early on. Some items are particularly noisy too. On a friends car with a Peterson external oil pump, it would max out the knock sensor by like 2000 RPM.


Aaron, can you post up that same pull but with smoothing set to 0?

 

not sure if that's the record but it's way up there. My setup gets me 600awhp on 93 octane at 30psi. I did have to decrease the knock sensitivity in the 3500rpm area where it picks up some false knock but the rest is stock settings and knock free. I haven't put det cans to it but it would be interesting to try.

 

Wow! That a ton of power for 92oct....make me very jealous.

 

Nice job.

Since you asked. I believe the most we've ever seen here, using 93 and 94 (no longer available here, the 94) was about 585. No alky injection, no octane boosters, just straight pump gas. If you want to find a pump gas Dynojet record look at Dynoflashes old threads, he dyno'd a few cars we did here on the Dynojet there and made big power, it was the "other" Bad Bish I believe.

My car made 572 I think and ran 9.72 at 145 mph on straight 93 octane.

If I take the highest, which I remember being 585 and add 13% it gives me 661 whp. I'm not getting caught in an argument or ***** measuring contest over it! haha

These engines were 2 liters by the way.

OK, I remembered doing Nick Andy's car and went to look in his file. I made 618/446 whp on his car on 93 octane, that car actually has our 2.3 liter stroker in it. It's a BEAST. That comes out to 698 whp if we add 13%. I did that car on 5-12-08.

Not many guys want to really push hard on pump gas anymore, it was a thing I was really working on then. Now with E85 most guys want a mild tune on pump and a kill tune on the E85.

Anyway, great looking dyno graph!

 

650-700 awhp on pump gas is pretty incredible, david were you letting knock voltage be your guide? I don't recall you ever mentioning det cans.

 

Knock voltage and torque is what I use. Torque is the best guide to what's going on.

I bought some good det cans from Snap on, never used them.

 

Didn't big Al do something like 700whp on his old 42R setup on pump gas once? I may not have my facts right but I remember the 3 amigos pump gas craze was going on and Al gave it a try but said he'd never race it like that.

 

Looks good aaron, cant wait to get my car back on the dyno with this cold air.

 

Making 700 whp on a GT42r should be an easy task on pump gas.

 

Thanks for the info Dave. No worries on the "measuring" I keep close tabs on what your dyno does vs ours and the 13% never seems to vary much at all. I did ask after all too

Yeah I believe very strongly in good fuel (E85 in particular) and dont push pump tunes for anyone but myself. After having some issues because of it before I said I was never gonna do it again but I had to just once

This time around it made 1 ft lbs more because of how I have the timing vs when I made the pull at 25.7 so I feel good about the tune, the plugs looked good, the car sounds fine this morning and rips like it always does.

03White- I will grab the DRF at the dyno today, it was 1030 when I got done last night so I sent myself the jpg and beat feat for home (too long a day).

aaron