Slower after header install

[Trillbro]

Stage 1 MT-82 on e30. I ran the 6.56 last year. The DA and slope in that run were better but not sure how I lost 4 tenths 60-130. Will a tune help me make a faster pass? I was expecting to run closer to my fastest pass with the headers I had installed

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[Q6543]

You can’t compare negative air to 950+, a 1500 ft differential is huge

Negative is basically seeing fractional boost

Did you go catless? That’s the bulk of the gains on headers N/A

 

[Trillbro]

You can’t compare negative air to 950+, a 1500 ft differential is huge

Negative is basically seeing fractional boost

Did you go catless? That’s the bulk of the gains on headers N/A

I'm boosted but yes catless. I didn't think that much DA would make a huge difference.

 

[robvas]

Did you only do one run? Did you datalog it?

 

[Trillbro]

Did you only do one run? Did you datalog it?

No did about 7 runs last night. That was my fastest time. I tied it starting in 2nd gear but spinning a little bit. I didn't log it.

 

[smurfslayer]

what is that huge dip in acceleration and speed on the 4th section of the graph? You're losing huge time there. Is there a corresponding power curve dip?

 

[robvas]

No did about 7 runs last night. That was my fastest time. I tied it starting in 2nd gear but spinning a little bit. I didn't log it.

First thing to look at could be timing and knock. Maybe your fuel isn't as good as last time

 

[robvas]

what is that huge dip in acceleration and speed on the 4th section of the graph? You're losing huge time there. Is there a corresponding power curve dip?

Shifting, MT82D4 3-4

 

[Trillbro]

what is that huge dip in acceleration and speed on the 4th section of the graph? You're losing huge time there. Is there a corresponding power curve dip?

Shifting from 3rd to 4th gear. Pretty sure there's tons of clutch protection in the tuning on the mt82 cars. That's shifting as fast as I can

 

[Q6543]

Is it stage 1?
Yes D/A affects boosted cars as bad if not worse, hell even the 42-55 temp difference is a big deal.

You’re starting at like 40-45 mph right?

 

[Trillbro]

First thing to look at could be timing and knock. Maybe your fuel isn't as good as last time

Thanks! Next time I get the car out I'll try and log it. Looks like it's going to be cold for the next few weeks 🫩

 

[Trillbro]

Is it stage 1?
Yes D/A affects boosted cars as bad if not worse, hell even the 42-55 temp difference is a big deal.

Yeah it was pretty humid last night too. I'll see if I can replicate the temp and DA sometime soon

 

[Gojiras breath]

I'm having an issue with my procharged f250 godzilla with hiflow cats and longtube headers at wot. I finally contacted procharger to see if this was common and there was a fix. They looked up the serial number on it and said it was ordered with stock exhaust (local.shop bought it). They said headers will cause it to run lean on their tune. If you click "headers" on the order box they will only sell a tuner kit.
GROK agreed also. Headers on a boosted car will cause it to run lean.
Is this a known thing? Is it correct?

 

[robvas]

I'm having an issue with my procharged f250 godzilla with hiflow cats and longtube headers at wot. I finally contacted procharger to see if this was common and there was a fix. They looked up the serial number on it and said it was ordered with stock exhaust (local.shop bought it). They said headers will cause it to run lean on their tune. If you click "headers" on the order box they will only sell a tuner kit.
GROK agreed also. Headers on a boosted car will cause it to run lean.
Is this a known thing? Is it correct?

If your engine has a mass airflow sensor it will see any extra air and compensate. Same goes for wideband O2 sensors.

If it is speed density that may be true. Or a carbureted engine. Headers probably won't change it enough to matter though.

A lot of people say the car "runs rich" with headers or without cats...

 

[Q6543]

No, that reads like a blanket cover your ass statement

My car didn’t “run lean” stock tune with headers.
And define “run lean”… no idea on a pc'd zilla, mostly coyote only in this forum.

I’d skip procharger all together after they botched this rollout so badly, company seems to be ran by hacks.

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