Supercharged VT 355 afm tuning

Holden/Delco Tuning. ALDL, OBD 1.5. Circa 1989 to 2004.
shane1
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Re: Supercharged VT 355 afm tuning

Post by shane1 »

The maf is a delphi 25168491, the intake air temp is in front of the throttle body.
Im thinking the same that the afm is having issues as i have refitted the std afm and even tho its pegged at 11000 hz it doesnt go lean it just stops measuring.
Im going to order another new afm and try it .
will try the adx file now
350rwkw with the std afm at 5600rpm it is going to be a good thing if i ever get it sorted!!!!
shane1
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Re: Supercharged VT 355 afm tuning

Post by shane1 »

a log with the std afm.
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The1
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Re: Supercharged VT 355 afm tuning

Post by The1 »

Your tune ramps up fine on the bench
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The1
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Re: Supercharged VT 355 afm tuning

Post by The1 »

shane1 wrote:The maf is a delphi 25168491, the intake air temp is in front of the throttle body.
Im thinking the same that the afm is having issues as i have refitted the std afm and even tho its pegged at 11000 hz it doesnt go lean it just stops measuring.
Im going to order another new afm and try it .
will try the adx file now
350rwkw with the std afm at 5600rpm it is going to be a good thing if i ever get it sorted!!!!
id be keen to see the maf, you may have a fake one, as the others i have had did the same thing, the genuine works fine.
GM Tech
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Re: Supercharged VT 355 afm tuning

Post by GM Tech »

This has happened to me before. Make sure you are not loosing boost at that point. Check the boost on the dyno to confirm.
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The1
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Re: Supercharged VT 355 afm tuning

Post by The1 »

Sent a Card MAF down for him to test, it was the MAF.
shane1
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Re: Supercharged VT 355 afm tuning

Post by shane1 »

It was the fact that the Delphi maf DOES not go above the 11500 Hz that was the issue yes it was
Genuine and I tried two different ones. I also tried ls2 , ls3 and had problems of varying issues with all of them.
The card maf in a 4 inch pipe was the answer to the issues .
When I get a bit of time I will write an in depth story on all this
As there is a lot of things that simply don't work in the real world compared to
A bench test . The car made 370 rwkw on 8 psi and drives Like a stocker. Thanks to
THE1 for his help on this .
If anyone is looking at going down the 300+ rwkw route with a vt
Save yourself a lot of agro and use the card maf !!!
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The1
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Re: Supercharged VT 355 afm tuning

Post by The1 »

the trend is pointing to the VZ versions of the MAF being limited to 11,500hz the brand new Genuine i had from the US went to 14,000hz though that is only 1 ive tested. I have a couple of used ones from the US coming that i will test, though Card MAF for high HP is the go plenty of range there.
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