Lnorm

Just put a 76 mm bb turbo on my lq9. Bored .030 over, arp studs and bolts throughout, forged pistons, 10:1, shaved truck intake, stock tb, Holley hp efi, comp 234/242 .602/.604 114 lsa, comp springs, 4" a to a intercooler, Holley 83 lb injectors, walbro 340 pump. As the title implies I have no clue where to start tuning for a/f or timing. I'm only running 7 pounds of boost. Right now I'm at 11.5:1 and around 12 degrees of timing but it starts breaking up as soon as the turbo starts to spool. It was a nitrous car until yesterday when I finished the turbo and I've never dealt with a turbo before. Is my timing way too low for such low boost? My stainless headers are turning blue?????? Please help!!!!! I will be getting it dyno tuned soon so I don't need max power but I'd like to drive it!!!! Anyone with experience with something similar????

LT1PWRD

iTrader: (2)

You're timing and afr are a safe start. But i would dial it in w/o any boost first. Make sure you have no drivability/lean issues first, then start your boost tuning after its 100% so you don't melt it down.

69-chvl

iTrader: (11)

Close your plug gaps.

69-chvl

iTrader: (11)

And you need a lot more timing for 7 psi.

giantrules

iTrader: (1)

Take a look at the turbo lsx holley custom calc in your holley software...the spark table demonstrates timing in relation to rpm and map. You can use this a jump off point to modify/create a base tune...reducing it to the 16x16 table will help with a basic understanding of the curve and not overload the eyes. Just my 2 cents as I am learning as well...experts please chime in...

Lnorm

Thanks guys. I did build this tune from the lsx 20psi tune but I took a bunch of timing out. I was worried it was too much. I have leaned into it a few times and got to 7 psi but it's a dog! It was surely faster n/a. Should my under boost timing remain the same as n/a or should it be less? I was 35-40 in some areas n/a. I was running a 175 shot of nitrous before. I was under the impression 7 psi would be at least that much hp. Was I misinformed????

Lnorm

How much more to start?

Lnorm

I have non projected 7 heat range ngk (br7ef) at .030 now. Close them more?

ls3fox

What fuel are you using?

Lnorm

93 octane. I pulled a plug real quick last night and it was sooted up and black. I'm gonna pick up new plugs today and swap them out. These plugs were put in about 2 weeks before u bought the turbo so there's a few nitrous pulls on them.

forcd ind

iTrader: (7)

Use the data log feature, it should show something during the breaking up area, then tune that section

69-chvl

iTrader: (11)

A lot of folks run n/a timing up till around 6-7psi and then "dump" the timing fast from there. Around 7psi I'd be in the low 20's, and timing bottomed-out by around 10psi. But, your doing it right by starting low and working your way up.

Plug gaps are interesting. Different coils, wires, cylinder pressures all have an impact on what gap in needed. You may not break-up if you add some timing to it. But, I was breaking up even with low boost with my factory coils at anything over .022. Some guys are like .018. I'd go tighter for sure, wont hurt anything and is easier on the ignition system.

Old Geezer

iTrader: (3)

Post the tune and data logs...

Lnorm

I'm computer stupid! I'm not sure how to do that. I did look over the data logs last night but don't see anything crazy happening when it falls on its face. I'm thinking maybe the timing is going so low it's just loosing all the power. I was told that since it's 10:1 scr that I'd need the timing this low. Maybe not?

Lnorm

I'd like to thank u guys again for helping. I really do appreciate it. If u ever need heating and Ac questions answered I'll gladly help! Lol

69-chvl

iTrader: (11)

Try a little more timing and then close the gaps...very easy to do and then you can move on if necessary.

Lnorm

I grabbed plugs on my way home. They didn't have ngk but they supposedly had the autolite equivalent. Got home. Pulled the hood and down pipe, pulled a plug to compare and the damn plugs they gave me were projected tip! Closed all my gaps to .022" and put them back in. 😡. I did change my entire spark map to the turbo lsx 20 psi tune from the Holley file. It seemed to run the same. I'm hoping the spark is blowing out but it's not going rich in the logs so I doubt it. Getting lost now!

69-chvl

iTrader: (11)

Spark blow wont really change the AFR, if anything you would see lean as the o2 sensor is picking up air that is passing through (unburned air).

The LSX turbo file was for an engine using race fuel...be careful running that file on pump fuel w/o meth etc.

Lnorm

I meant lean not rich I don't see any change in a/f. I tried to find out more about that tune but couldn't find anything. I pulled timing from the boost are. U mind taking a look? I took a couple pics of it.

Lnorm