ptuomov

The modesty (if any) comes from the fact that I don't want to look like an a$$hole confidently stating all these dynojet numbers and then having to show a time slip with 110 mph trap speed... :O

I have to say, though, that John's system makes pretty big numbers straight out of the box. There's probably another 50-100 or so dynojet hp on the table because the car was run rich and retarded with suboptimal boost profiles in a 100F smoky shed in Kentucky in the middle of July. (Contrary to my expectations, not everyone was related to each other... Actually the place reminded me of the part of Finland where my wife is from.)

How much turbo power one can make all depends on one's tolerance for knocks, of course. In those conditions, 14 psi will show knocks in the mid range. Above 5600 or so, 14 psi didn't give any knock events, though. There's room to make more safe power in the top end.

Usually, I think it's the knock retard in stock settings. In stock settings, the knock retard is a case of the cure being worse than the disease! (Heads up from Jim Morton on this topic saved us a bunch of time.) In our case, it's not that. I am not exactly sure what it is in our graph.

Which brings me to another point, namely that this stock engine is for me to waste in learning how to tune these cars and experimenting with things. I don't want to practice on the engine than Jim built me.

My next step with this engine is to take these torque curves and data logs and come up with a couple of rpm-specific boost profiles. Then, with those profiles we'll do another couple of days of tuning here in Boston. I need to book some time on a Dyno Dynamics dyno here in MA.

Oh, yeah, and currently the car is too loud for our street...

Yes, we logged a bunch of stuff. AFR for the WOT pulls was all over the place at tip in but then stabilized in mid 11s. As I said, the tune is not there yet.

ptuomov

The work done so far is all John. I'll be taking it from here. Let's see if the dyno numbers get better or worse! ;-)

One more thing. During the 900 miles on highway in varying traffic conditions, the car guzzled somewhere in the 20-22 mpg. Way better than my V10 M5, which also makes less power. No wonder that BMW is going to turbos in gasoline engines as well.

AO

Sounds like the dyno you were at was barely a dyno. Having a good dyno with an experienced tuner is worth the money.

No knock at 14psi is a good thing, but there is still something going on there. Maybe it was just the dyno? Could also be the wide variations in the AFR from cylinder to cylinder. Hacker posted a thread where Todd (aka The Mad Scientist) had 8 WBO2 sensors hooked up to see what the variation was from one cylinder to the next. I think he found it to be about 1.5 points from the high to the low. Not bad considering the C6 Vette has been documented to be up-wards of 3 points variance.

Anyway, it's something to consider. You're probably reaching the limits of our fuel injection system. The batch fire is less than ideal for your high HP application.

Have fun with the tuning.

Bill Ball

That curve doesn't look like turbos. Huge torque down low. Spooling up right away. 600 ft-lbs of torque at 3500 RPM sounds like a lot of fun to me! Enjoy!

Fabio421

You should post it here. Somehow my name is listed in front of Mike Simards beast and SeanR's name is listed in front of a rear mount turbo car. I sent the info on Mike Simards car but I sure don't want it to look like I'm taking credit for it thats for sure. And I'm skeptical about the rear mount turbo dyno # that SeanR posted. Who's car is that?

Rob Edwards

Whoa. Nicely done, Tuomo/John K! LOL at it being too loud for your neighborhood. Sounds like my neighborhood...

ptuomov

Bill --

A side note: I also managed to boil the fuel... I should start a club with "FuelBoilers" window decal! I say I not we because this was not a team effort, I did the half-finished fuel system (aka the fuel boiler) all my own.

Your note on this being a potential problem note saved our asses, since we immediately had it on my top four causes list. Thanks.

We found an effective temporary solution in about 3 minutes. Five gallons of cool guel in and the rest of the day we run the car with the A/C full on, except turned it off for select WOT pulls. The stock fuel cooler uses the A/C residual and it works!

Best, Tuomo

ptuomov

This is not ready to be posted in any databases yet. Let me work on it for a month or so first.

ptuomov

Lights come on when I drive at night... When I parked in my garage, my wife was laughing her *** off with hands on her ears.

I'll try to record some audio at some point. It doesn't sound like a European sports car, it sounds like the Hells Angels on identical bikes riding fast in a formation. That's what you get from not having a cross over, one needs to go in ASAP, not for power but for sound. But these are all matters of taste.

Bill Ball

Yeah, George and I were putting in 5 gallons of "cold" fuel every 45 minutes to alleviate the problem during our drive to the race. Note that our big Aeromotive fuel pump was mounted EXTERNAL of the fuel cell with no internal pump, which exaccerbates the vapor lock issue, as did the increasing altitude on our drive to the race. We didn't have a problem during an hour or so of dyno runs, but we weren't putting down your HP and torque. So, we'll be moving the pump in-tank, adding a fuel pump speed controller and replacing the fuel line with larger lumen size.

ptuomov

Running the car at idle in our Kentucky smoke sauna is probably almost as bad as the high altitude! ;-)

The reason why it boiled is that we kept losing the ST cursor every time when the car was shut down. So we had the car idle a sometimes between pulls.

Later, with the A/C it didn't have any problems.

This to me proves that in our case it was primarily the fuel pump heating the fuel by pushing huge volumes back thru the stock-sized returns line. What I put on the car really deserves the name fuel boiler!

ptuomov

But doing it yourself is priceless!

John understands this stuff, but I went to get the car home early precisely so I can do as much of this myself as possible.

So I basically called John on Thursday that I want the car back on Saturday since my inlaws are coming to town. Having the car here will help avoiding long awkward silent moments with the father in law! ;-) Of course, John couldn't get a free day from his regular dyno shop with no notice, so we had to drive out to this other shop.

Now, they are a big name shop building some impressive cars, but they are all about N/A carburated stuff and they couldn't car less about anything which has electrons flowing thru it. They grudgingly seemed to make an exception for spark plugs and wires, although I am sure they would rather use glow plugs if they'd work with gasoline! ;-)

The stuff they knew right off the top of their heads about some other customer's (who was an engine builder himself) carburator having a third, trans brake circuit and therefore not ever running well on the street makes me believe they know what they are doing when doing what they do. I don't want to leave the impression that they didn't know what they're doing as far as what they do goes -- that would not be true and even if it were true I couldn't tell the difference.

It's most likely the boost controller hunting around the set point. We didn't do anything to optimize the controller parameters there. We couldn't since we couldn't log the boost!

It's probably not the unequal filling of cylinders since there were no knocks high up.

The engine Jim Morton built me has the flow equalized to 280-285 CFM for all runners. The resonance tunign one can never get exactly right since the runner lengths are fixed, but in terms of just the straight flow Jim's solved that problem.

Fabio421

Come on, it's not like you're still driving around with those test pipes on.

BTW, it's a shame you guys didn't dyno the car with those test pipes. It would be interesting to see the difference a full exhaust makes in power output.

ptuomov

It's all relative. I happen to live here:

http://en.wikipedia.org/wiki/Weston,_Massachusetts

Those test pipes had the gt2871r flanges (same bolt pattern, slightly smaller holes than the gt3071r). John's got them, and may run some experiments with them.

I would expect the difference to be surprisingly small. First, the turbines will spool earlier, but on his car the turbines spool so ridiculously early that it's not going to make a difference. Second, the test pipes could allow one to run more boost, but we don't need to run more boost. Third, the exhaust back pressure will be lower at top end with the test pipes, but with the stock cams that's of little consequence. Now, with bigger cams I would expect those pipes to make a real difference.

When I drop in Jim Morton's low compression engine that can both run high boost and has bigger cams then maybe I should make my own test pipes with gt3071r flanges.

Hilton

Very drool-worthy results.. can't wait to see how you kill this engine or gearbox, and where you get to with the learnings.

On the fuel cooler - it wasn't until I actually pulled one of mine off the car (replacing the AC o-rings) that I gained an appreciation for how much cooling effect it can provide. The internals of it are very "cool" for something that on first glance at it on the firewall makes you think "WTF is the point?"