[ZeroBlade597]

I recently had the Whipple 2.9 installed on my '17. Im seeing a calculated boost anywhere from 8-10psi at WOT. i ran a scan on VCM Scanner and had a 2 degrees of KR at WOT. When i picked it up from the shop they said they saw some knock and were thinking it was the gas. I run 93 Chevron/Texaco. I attached screen shots to the post.


Has anyone else seen that much boost on the 3.625 pulley?

I just wanted to get some insight from anyone else about this.

[Ryephile]

Fuel trims in PE are on point, but what are the PE targets? Are you running a wideband?

It's not a horrible KR count, but zero KR is ideal. I don't know what WOT timing a LT4 normally runs, but 4.5° advance seems pretty low.

[ZNix]

Can you send me a log? buickgnix@gmail.com. It may be torque management showing as KR. But if its legitimate KR, you should not be hammering on it until its solved. I don't think you are logging enough of the PIDs here. I can already see that TM is closing the throttle. You are commanding 100% pedal but only seeing 85% or so TPS.

Did the shop tune it or is it a canned tune from Whipple?

Originally Posted by Ryephile

Fuel trims in PE are on point, but what are the PE targets? Are you running a wideband?

It's not a horrible KR count, but zero KR is ideal. I don't know what WOT timing a LT4 normally runs, but 4.5° advance seems pretty low.

Zero KR is the only KR you should ever see.

[ZeroBlade597]

The shop tuned it, I don't have a wideband. I want to say the afr was around 11.5 when it was dynoed.

What other PIDs should I try logging?

I can send you the log when I get home late tonight.

[TJay74]

I would add around 10-20 % of E85 and see if the knock goes away. If it does it is timing induced knock, otherwise it could be false knock or torque management as ZNix is suggesting

[ZeroBlade597]

Originally Posted by TJay74

I would add around 10-20 % of E85 and see if the knock goes away. If it does it is timing induced knock, otherwise it could be false knock or torque management as ZNix is suggesting

I was going to get some race fuel tomorrow and do another log and see if it goes away.

Im a little wiery because of the higher boost level. Whipple advertises the 3.625 to make 8psi with the 7in crank pulley.

Lowering the boost pressure should help if it is real knock correct?

[ZNix]

I have a feeling its only TM kicking in, thankfully. The timing is WAY low and the AFR is rich. The shop should be fixing this. I can't believe they let it out the door with some knock. They should have added some better gas and dialed it in. At your expense, but still.

If you are seeing 11.5 on the wideband, that is too rich for these motors. DI motors don't like to be that rich, even under boost. I think you should take it to another tuner my friend. Or you could head over to the HPT forum and READ READ READ. Order some Gen V books and read more. Tune it yourself. You have HPT.

Ill look for your log. I can send you the PIDs that I use for my 6gen. Its only a bolt on car, but it should have everything you need. The only one I may not have is the boost PID, but you already know how to add that.

[ZeroBlade597]

For the afr I was going off of memory, the shop didn't get a clean full pull. They said it was spinning on the Dyno and to take it back up there when I get some new tires. They did add some race fuel when doing the Dyno pulls.

What afr would be ideally safe?

Thanks for all the info, I'll be sure to check out the other forum.

Thanks to YouTube I was able to learn a little bit how to operate hptuners scanner

[ZNix]

Originally Posted by ZeroBlade597

For the afr I was going off of memory, the shop didn't get a clean full pull. They said it was spinning on the Dyno and to take it back up there when I get some new tires. They did add some race fuel when doing the Dyno pulls.

What afr would be ideally safe?

Thanks for all the info, I'll be sure to check out the other forum.

Thanks to YouTube I was able to learn a little bit how to operate hptuners scanner

If they added race fuel and were still seeing knock, I am thinking torque management. This is good. We don't want to see real KR, that is engine damaging.

From what I see, boosted LTx cars are somewhere in the 0.81 - 0.85 lambda for AFR ratio. That's around 12.0 - 12.5 AFR. On the scanner, its best to be logging things in lambda if you are using a wideband.

These cars use a torque based controller. The computer knows that at X pressure ratio and Y RPM, the car will make Z torque. There are limiters in the computer that can change the power output of the motor depending on certain conditions. This plays into traction control, driveline protection, etc. This is why we are seeing Torque Management close your throttle and limit the timing advance at WOT.

[parish8]

there are some respected tuners around here that tune to 11.5/1 afr when boosted and others that swear by 12.8/1. when I was di only I went on the lean side just to stretch out my fuel system but it didn't seem to help or hurt power or knock compared to the richer settings.

the knock sensors seem pretty sensitive on these things. do people really tune to zero knock?

[ZNix]

Originally Posted by parish8

there are some respected tuners around here that tune to 11.5/1 afr when boosted and others that swear by 12.8/1. when I was di only I went on the lean side just to stretch out my fuel system but it didn't seem to help or hurt power or knock compared to the richer settings.

the knock sensors seem pretty sensitive on these things. do people really tune to zero knock?

You can numb the sensors down a little if you are getting false knock.

You should always tune for no KR in my opinion. Even if its false, edit the sensitivity. KR is pulling timing, and I would prefer to have full control of what the actual timing advance is.

[KingLT1]

To me it looks like a band-aid tune till you get some tires on the car and take it back so they can actually tune it correctly. It's rich, no timing, shifts too early, and TM should not be kicking in.


Adjusting the knock sensors is a must on these cars...they pull timing stock.

[ZeroBlade597]

Update:

I ended up putting 2gals on 110 race gas into about a half tank of 93. stillgetting KR.
Waiting on wheels and tire to get here and taking back to the shop to get tune adjusted.

[ZeroBlade597]

Here are some screenshots from the last log