Tuning issues and what to do about them???

[Robert Walton]

As posted elsewhere I kinda got my butt handed to me by a stock LS1 today.

The car was detonating bad at the top end and the car just didn't seem to pull like its parts should.

Here's the particulars:
Coolant temp rock steady at 175*
Ambient temp was 60 something.
93 octane gas
16-17 psi boost
60psi fuel pressure at max boost
255 on the MAF
0.890 O2 volts
Turbotweak 93 chip. I forget what timing Eric put into it.
42.5 injectors
43 psi fuel pressure no vacuum
RJC pwer plate

If anymore info is needed just ask.

My first question is this. Distributorless and port fuel injection. Outside of a little tweaking of fuel pressure or going through piles of chips,how are these cars "tuned" ?

Alky is a no no right now and I feel like it is a bandaid for my current problem,massive detonation. Same with Drag Radials

What I am looking for from the board are some starting points.

 

[mybuick]

it looks like your lean and the maf is pegged. i would put a lt1 maf and a transulator and look for exhaust leaks and turn up the fuel press to 43 with line on.

 

[750H.P.V6]

I have a question about your WOT O2 voltage. Is that 890mv on your scanmaster, OTC 4000 or? Different scan tools will give you different readings. FWIW, it wouldn't suprise me if the LS1 wasn't "stock" but even in stock trim they run 105-106 MPH trap speeds.

Neal

As posted elsewhere I kinda got my butt handed to me by a stock LS1 today.

The car was detonating bad at the top end and the car just didn't seem to pull like its parts should.

Here's the particulars:
Coolant temp rock steady at 175*
Ambient temp was 60 something.
93 octane gas
16-17 psi boost
60psi fuel pressure at max boost
255 on the MAF
0.890 O2 volts
Turbotweak 93 chip. I forget what timing Eric put into it.
42.5 injectors
43 psi fuel pressure no vacuum
RJC pwer plate

If anymore info is needed just ask.

My first question is this. Distributorless and port fuel injection. Outside of a little tweaking of fuel pressure or going through piles of chips,how are these cars "tuned" ?

Alky is a no no right now and I feel like it is a bandaid for my current problem,massive detonation. Same with Drag Radials

What I am looking for from the board are some starting points.

 

[Joe Lubrant]

it looks like your lean and the maf is pegged. i would put a lt1 maf and a transulator and look for exhaust leaks and turn up the fuel press to 43 with line on.

Just the opposite...02's at 890mv...big time Fat Rich!!

If TT Chip has max fueling for the 42.5 Inj. its way to much for 16-17# with a 51 Turbo. Heck 36# Inj. can support that turbo & 16-17 boost level.

Overly rich condition will produce detonation type symptoms.

Joe

 

[Robert Walton]

I have a question about your WOT O2 voltage.Is that 890mv on your scanmaster, OTC 4000

OTC 4000. Yes it was in road test mode. I did a recorded pass just to see


"If TT Chip has max fueling for th 42.5 Inj. it's way too much for 16-17#" Joe Lubrant

O.k so what is suggested here? Drop the fuel pressure? Send the chip back to be reprogrammed? Since I don't have a wide band yet I need to take a trip to the dyno.

 

[Razor]

No, put a scanmaster on the car.. and watch your O2 levels. Erics chips are programmable so changes can be made without taking the chip out. Problem is with dinosaur scantools.. help is tough when nobody uses those.

Target O2's in the upper 700's on a scanmaster.. should get the job done. If your picking up knock.. then you need to see whats up.

We are all ASSuming all your numbers on the scantool are within normal ranges.. like BLM, AF, IAC, TPS, MAL, etc...

And that the motor is sound mechanically with normal leakdown.. and there isnt a 1/4 inch thick crust of carbon on top of your pistons..

FWIW, you'd probably be faster with a stock turbo..and yes.. no alky/race gas till it runs cleanly like it should.

 

[Robert Walton]

We are all ASSuming all your numbers on the scantool are within normal ranges.. like BLM, AF, IAC, TPS, MAL, etc...

And that the motor is sound mechanically with normal leakdown.. and there isnt a 1/4 inch thick crust of carbon on top of your pistons

Please explain what "normal" numbers are. I know this may all be in the all knowing search area but.....

Leakdown is less than 10% on all 6 cyl. I also did a top engine clean with X66 twice. That did help.

Just what puzzles me is detonation with the nice cool weather we are having now. Yes I could hear it,I'm a trained professional :biggrin:

 

[turbot2496]

Well... I had a bad boost gauge that was causing my detonation problems. Thought I was running about 15 pounds when I was actually running?????. Although my 02's weren't as high as yours. Anyway easy to check and see if your gauge is reading correctly and your not running too much boost.

 

[Robert Walton]

more info

O.K.

MAF pegged at 255
O2 volts on my OTC 4000 was 0.910v
BLM was 128. It's my understanding though that Eric's chips lock at 128 at WOT.
Knock retard was 9* at the top of 2nd gear and dropped to 7* through third.

Question,my Turbotweak chip has a +4* and -1* range on timing. If I have 9* retard and I take out 1* with the chip does that make it now 8* retard? So what is the point of taking timing out if this is the case?

 

[turbot2496]

Question,my Turbotweak chip has a +4* and -1* range on timing. If I have 9* retard and I take out 1* with the chip does that make it now 8* retard? So what is the point of taking timing out if this is the case?

No...

Knock is detected by the knock sensor. The degree or severity of the knock is determined by the ecm from readings from this sensor. Once interpreted the ecm retards timing to git rid of the knock.

Lowering the timing in your chip could help with the problem but I doubt one degree will fix it.

How much boost are you running??

 

[Robert Walton]

How much boost are you running??

17# HD actuator. it WILL NOT go any lower than that

 

[turbot2496]

So are you saying that your boost gauge is reading 17#'s of boost at WOT?

 

[Robert Walton]

So are you saying that your boost gauge is reading 17#'s of boost at WOT?

yup

 

[turbot2496]

Ok. Now if you have a Turbotweak chip you can take fuel out. By your o2's you are running quite a bit rich..... if your o2 sensor is reading correctly.

Is the car blowing black smoke? Is there a strong fuel smell in the exhaust? Also if she's rich the plugs will look black.

If you can confirm that the car is indeed running rich and the 02 sensor is reading correctly then you can safely take some fuel out using your chip.

Also if you would like to lower your boost till you can figure this out, there is a way even though you don't have and adjustable wastegate. You can simply run the vac line from the turbo straight to the wastegate bypassing the wastegate solonoid. This will lower your boost some. Some cars can't handle 17#s on pump gas.

By the way what is the initial timing in your TT chip? It should be written on it.

 

[750H.P.V6]

Robert,

890-910mv on an OTC 4000 isn't as rich as you've been led to believe. On the OTC 4000 the reference voltage from the 02 sensor is 500mv not 450mv like an OTC 2000, Direct scan or Scan master. You need to take your OTC 4000 readings and multiply by .9 to get an accurate comparison. Your 890mv O2 on your OTC 4000 is really around 800mv when talking to others tuning with a Scan master, Turbo link etc.

To answer your question about WOT timing vs knock attack strategy/retard from the ECM here's what I can tell you as related to me by Tom Chou (Tom works for Delco and does ESC calibration for a living). If you have a car running 20 degrees of timing with no knock at WOT and you introduce 1 degree additional timing which results in knock you will have to retard the timing 8 degrees to make the knock cease. With this in mind if you are able to reduce your WOT spark advance by 2 degrees you should be in good shape.

I hope this makes sense.

Neal

MAF pegged at 255
O2 volts on my OTC 4000 was 0.910v
BLM was 128. It's my understanding though that Eric's chips lock at 128 at WOT.
Knock retard was 9* at the top of 2nd gear and dropped to 7* through third.

Question,my Turbotweak chip has a +4* and -1* range on timing. If I have 9* retard and I take out 1* with the chip does that make it now 8* retard? So what is the point of taking timing out if this is the case?[/QUOTE]

 

[turbot2496]

17# HD actuator. it WILL NOT go any lower than that

Oops sorry it was late and I was tired and didn't catch this. Running it tuner style probably won't help sorry.


All of the ones like that I've seen are adjustable. You can lengthen the rod to lower the boost by unscrewing the end piece. Thats how the one on my car is.

If you check out
https://www.kirbanperformance.com/index1.htm and look at the pick of the HD one he sells you'll see what I mean.

Is yours different? Would not be hard to modify it to lengthen the rod if so.

 

[Robert Walton]

I ordered a standard actuator from Kirban a while back. My PT51 is different. I need to order one from Full Throttle. I know they are cheap but right now funds are tight at my house,THANK YOU CAR MANUFACTURERS FOR THE STUPID EMPLOYEE PLAN.

 

[turbot2496]

Whats the initial timing in that chip?

 

[QUIP'6']

eric locks the maf to 255 on his chips for fuel accuracy

 

[Robert Walton]

Whats the initial timing in that chip?

Hell if I know. I did remove 1* accross the board and knock retard dropped from 9* to 2* :biggrin: