05 GTO Tune Help

[Jtunes05]

Alright I'm new here so don't hound me to hard 😂 I got my GTO tuned at a local performance shop and it doesn't seem to run right, it backfires a lot and it has close to no power on the low end (have to get 3500+rpm to see the power everything else is gutless), I normally have to rev to 1500rpm and let the clutch out very slowly or else itll bog down and not go anywhere and sometimes it takes a couple cranks to start and I can tell it runs rich. I will be ordering a wideband soon so I can get the afr and see what that says. The car is tuned on E85. Ill attach the build list along with my tune file and a data log.

The engine is a ls1 bored .030 over (Yes I know, no good...) Its got a texas speed MS4 cam, 80lb injectors, patriot stage 3 heads, I still have the stock intake manifold.

Thanks in advance! I just want this thing to run right, got some races coming up that I wanna compete in but I'm not taking the car as it sits now. I already blew up my ls2, that's what this is replacing until I can build another engine for it.

[SiriusC1024]

80lb injectors? Tune says ~36lb. What injectors, exactly, are you using?

Cylinder volume is incorrect. Should be 0.71925.

Stoichiometric AFR 19.64? E85 is 9.8, assuming it's truly 85% ethanol.

Spark is pretty advanced.

Fuel trims aren't working.

[13qtr]

it shows he's got the double stoich, halve ifr and ivt terms for the huge injectors. needs to log injector spray time and air mass. In the log, i thought the timing was low, didn't match the tune. like it's pulling timing for some reason.

[SiriusC1024]

I don't think that's the way to do it. Should have correct injector data and realistic terms based off that.

[SiriusC1024]

I'm getting 10.11:1 CR and 8.08:1 DCR. I doubt there is any benefit to using e85 compared to pump gas. That trick works on the Coyote Mustangs because of the higher respective compression ratios. Using pump gas takes away the variation of e85, which is actually anywhere between e51 to e83. Just because you're able to put in more timing before knock doesn't necessarily mean more power. Has MBT been recalculated for this combo?

[Jtunes05]

I'm getting 10.11:1 CR and 8.08:1 DCR. I doubt there is any benefit to using e85 compared to pump gas. That trick works on the Coyote Mustangs because of the higher respective compression ratios. Using pump gas takes away the variation of e85, which is actually anywhere between e51 to e83. Just because you're able to put in more timing before knock doesn't necessarily mean more power. Has MBT been recalculated for this combo?

I?m not sure what all they did, I just put the engine in and sent it to them because I don?t have any experience tuning they may have recalculated the MBT but I doubt it. And I was kinda iffy on them recommending e85 because I didn?t think it would be needed for a non boost application.

What would you recommend me change in the tune? Without a wideband I think Im fairly limited on the tweaking I can do but being new to this im unsure.

[SiriusC1024]

Find a new tuner or ask one of the guys on here for a remote tune. There's so much to change. Have the injector part number ready for them.

[SiriusC1024]

Is there a flex fuel kit on your car?
https://www.hawksmotorsports.com/200...flex-fuel-kit/

[kevin87turbot]

You have DTC's for your Passenger's side upstream oxygen sensor. That's preventing it from going closed loop. It'll run better once you replace that sensor.

The double stoich/halve IFR is the best method to tune the E40 ECM with injectors that exceed the 63 lb/hr ECM injector limit. However, the engine is running lean. It will need some more tuning. Several of us can help you get it dialed in. Part throttle can be dialed in with your stock oxygen sensors, but you'll need a wideband sensor to get WOT dialed in.

[SiriusC1024]

Good info.

[Jtunes05]

Is there a flex fuel kit on your car?
https://www.hawksmotorsports.com/200...flex-fuel-kit/

No I don?t have that. I just got a e85 supported pump and braided lines

[Jtunes05]

Is there a flex fuel kit on your car?
https://www.hawksmotorsports.com/200...flex-fuel-kit/

You have DTC's for your Passenger's side upstream oxygen sensor. That's preventing it from going closed loop. It'll run better once you replace that sensor.

The double stoich/halve IFR is the best method to tune the E40 ECM with injectors that exceed the 63 lb/hr ECM injector limit. However, the engine is running lean. It will need some more tuning. Several of us can help you get it dialed in. Part throttle can be dialed in with your stock oxygen sensors, but you'll need a wideband sensor to get WOT dialed in.

Yea I gotta get that done as well. Once I get that done I?ll be able to tell more and be more comfortable tweaking stuff on my own. Would you consider running 91 on its current tune and see what happens?

[kevin87turbot]

Yea I gotta get that done as well. Once I get that done I?ll be able to tell more and be more comfortable tweaking stuff on my own. Would you consider running 91 on its current tune and see what happens?

It's not set up for 91 octane at this point, but can easily be altered.

[Jtunes05]

It's not set up for 91 octane at this point, but can easily be altered.

What all would I need to change?

[Alvin]

The drivers side O2 looks unplugged.

IF your going to go E85 you absolutely must have a sensor to go along with it. The E content varies greatly from pump to pump and from time of year. It is not appropriate to try to do this without a ethanol content sensor.

The timing looks OK. The VE looks like it can use some help which will give it some driveablity back.. but hunting driveablity with unknown E content is pointless right now.

I will say.. This isn't a setup that will pick up much at all with E85. I wouldn't waste the time or effort for something that might make less than 10 rwhp. Honest.. I'll bet E on this setup might make 5 rwhp if your lucky.



Saw someone above flag cylinder displacement being off. It is.. most 05-06's are off from the factory. I dont' think it makes any difference since displacement is wrapped up in GMVE (sorta) but I change it to the appropriate value.

[SiriusC1024]

That timing looks ok for premium gas though? I thought it was really high.

He stated bored .030, so that's why I checked the cylinder volume. Didn't know about the factory disparity lol.

[Alvin]

That timing looks ok for premium gas though? I thought it was really high.

He stated bored .030, so that's why I checked the cylinder volume. Didn't know about the factory disparity lol.

Yeah I would fix the displacement but in the end I don't think it matters. GM had set them off in a lot of early LS2's. CTSV and GTO and I think Vette.. notoriously though GTO's

28 is on the very high end for pump gas.. It might not even be making power up there.

[Jtunes05]

The drivers side O2 looks unplugged.

IF your going to go E85 you absolutely must have a sensor to go along with it. The E content varies greatly from pump to pump and from time of year. It is not appropriate to try to do this without a ethanol content sensor.

The timing looks OK. The VE looks like it can use some help which will give it some driveablity back.. but hunting driveablity with unknown E content is pointless right now.

I will say.. This isn't a setup that will pick up much at all with E85. I wouldn't waste the time or effort for something that might make less than 10 rwhp. Honest.. I'll bet E on this setup might make 5 rwhp if your lucky.



Saw someone above flag cylinder displacement being off. It is.. most 05-06's are off from the factory. I dont' think it makes any difference since displacement is wrapped up in GMVE (sorta) but I change it to the appropriate value.

I will look into the sensor today when I get home. I was pretty sure I would need an ethanol sensor but the shop said no so I stupidly took their advice. All they told me to do was change out the fuel pump so I did. I didn?t even wanna run E at all I prefer my 91 but they insisted it would run better on E. I?ll change the displacement today as well.

So I will figure out my 02sensor and I will do some learning on tuning it on 91

[Jtunes05]

Also if I asked you for a email tune to get me on the street faster how much would you charge me?

[Alvin]

Also if I asked you for a email tune to get me on the street faster how much would you charge me?

You'd have to just check the site. www.pcmofnc.com

We go up and down on prices just to keep my workload OK. Kind of like a market price. When there is one head tuner.. we got to throttle it somehow.