I just saw a tuner who was flown across the country to tune a car put out a product that scared the he** outta me. It's not for a Corvette but the process is the same. Tell me if this sounds as bad to you as to me:
First, it made great, HUGE, power: 677 rwhp and 612 rwtq out of a turbocharged 3 liter engine.
BUT:
1. With huge injectors he claims the idle injector duration is .3 ms. Can you start and stop an injector that quickly?

2. I don't know what tuning software he is using, but claims to be "offsetting" the MAP values by a factor of 1.04???? WHY?

3. Granted it's a fully forged motor, he is running 1.75 bar of boost (what is that, about 21 pounds?) with an A/F that is always 12.5 OR HIGHER.

4. At peak torque (where I'm accustomed to running the A/F a little richer than at peak HP, he is running it leaner, 12.9, then back to 12.5.

5. At peak HP, he's running 24 degrees of timing, with pump gas, and 21 pounds of boost.

6. AFTER one dyno run for these WOT readings, THEN he goes out to street tune the MAF table. Shouldn't he do that first???

This is the FIFTH engine this builder/tuner has put together for the same customer, all four previous have popped. Anybody else here think they know why?

If this is normal, acceptable tuning, please tell me, because I'm really confused by it.

 

I have a fuel injector flow bench and can state with confidence no injector I've ever tested would squirt any fuel with a 0.3 ms pulsewidth. I would leave the MAP sensor output alone unless I had a reliable calibration table for it, and I agree with dialing the MAF sensor in first. As for the rest of the parameters, they sound to me like the path to maximum power and minimum longevity.



Jeff

 

So is this "tooner" also doing Corvette work and we need to steer clear of his workmanship?

 

Is this a direct injection engine? They seem to run leaner with boost... it's weird.

0.3ms my ***. There's no way an injector is stable down there... not even the $100 a piece Injector Dynamics ones.

 

Maybe this vvv is because of this ^^^


Sounds pretty scary to me. Even for direct injection.

I also agree with the .3 ms. Everything I've found, under 1 ms they start getting difficult to control.

 

It's not a direct injection engine. Everything about this tells me my friend will be buying engine #6, real soon.

Oh, and I converted BAR to pounds of boost incorrectly, it's 25 pounds of boost.

 

2 bar is 14.7lb of positive boost pressure, so 1.75 is about 10psi off the top of my head give or take a pound.

 

Yeah, you need to subtract atmospheric pressure from the absolute BAR. If you're at sea level, then it's 25-14.7=10 psi. As Bill stated below.

 

I believe most people talk about positive manifold pressure when they refer to boost. Only dorky engineers (like me) think in terms of absolute pressure.

 

o wow, so many things wrong in that first post...just wow.

 

Hey, you callin me a dork? J/K