My tuner gave me a tune with 2 maps: one for 24 psi + pump gas, and one for 28-29 psi + race gas. The race gas map is automatically used when a higher load is detected. So (in theory) I don’t need to do anything to switch maps; just add race gas, crank up the boost and I’m all set.

On the dyno, the pump gas map made 332 whp @ 24 psi, and the race gas map made 361 whp @ 28-29 psi. The boost tapers down to 21-22 psi in each case, so the taper with race map is pretty extreme.

While this looks reasonable, on the dragstrip I didn’t see a big difference. I made several passes with pump gas/24 psi and several with race gase/28 psi. I prepped the car the same way as I did during the dyno session. Here are my best passes:

pump gas/24 psi:
60..……1.740
330……5.066
1/8…….7.823
mph.......86.470
1000…..10.188
1/4…….12.164
mph……114.460

race gas/28-29 psi:
60..……1.688
330……5.012
1/8…….7.776
mph.......88.720
1000…..10.152
1/4…….12.122
mph……115.730

As you can see, I didn’t gain as much ET/MPH as I would have expected based on the dyno results. I think it’s due to boost taper: after first gear, I never see peak boost again, only tapering boost. With my race gas passes, I looked over at my boost gauge after shifting to 3rd and 4th. In each case, the boost went to ~ 24 psi after the shift and tapered down. So this tells me that after 2nd gear, the load level is at the “pump tune” level and the race map was probably never triggered.

This may explain why we see a 2.3 mph difference in the 1/8, but only a 1.3 mph difference in the 1/4. In the 2nd half of the track, I was actually slower because I was probably running the pump tune while being pig rich from the race gas.

Does anyone see a solution for this? I’m thinking that I’ll need some type of hand held tuner to load in the race tune, rather than having it triggered by the load. Another idea is to shift at a lower rpm, like at 6000 rpm (now I shift at 7k). This will put me at a higher psi after each shift, and maybe switch over to the other map. Any other ideas or comments?

 

try the spring on your wastegate mod...to help hold boost...also tighten the acutator arm a little to..

the stock turbo or 9 turb does choke out...i saw the same thing when i turned it up to 28lbs as well...no difference in et at all.

it did not hold boost.

but i got a 3076r kit now....

 

Check for boost leaks. If your good there go to a gm boost solenoid or ebc.

 

Could be a lot of different things... boost leak, leaky DV/BOV, not enough preload on the WGA, leaky WGA etc..

Boost leak test with a bottle of soapy water to find small leaks

 

I have a solution:

Use 2 sets of maps. Not one set with extended load like you are using right now.
There's a patch available for our ECU's that will allow you to have 2 dedicated sets of maps. This whole one map thing is a .... well, not so good. Nothing is "triggered". You go into higher load at peak psi, but then you fall back to similar load as with low psi and not taking advantage of running more timing and leaner AFR on race gas. Ditch that tune.

Find a tuner who can flash you with switchable maps patch and tune. There's plenty here. Patch is free with a voluntary donation.

 

I agree.

I cant beleive you got tOOned like that Who does that?

 

Not to mention if you overboost your engine will be done.