VT 355 supercharged AFM issue

[ejukated]

haha MAP is the new Carby

EFI was once a magical black box too

just kidding, I like a good MAP ecu like the rest of us. MAF can be very good though

[The1]

well ill replicate this issue again hopefully over the weekend and then swap over to a vs v8 maf tune and see if that does it as well. Im suspecting it's the way the RPM code works with the different crank pulses, all the other MAF and Cylair code is the same as other models and the v6's

[Holden202T]

whats different with VT ? just sequential injection and cam signal from the dizzy ?

[shane1]

Ha ha we still get guys that take the efi off Ls engines and put carbs on , speedway guys are the worst for butchering efi stuff. I prefer to tune boosted engines with a map but N/A doesn't really matter.
Our BMW superbikes are only tps based no maf no map and make 220hp from 1 litre so end of the day if the code will let it everything works

[shane1]

The VT that has caused all this....

[Jayme]

verrrry similar setup to a mate of mine. I had it all set up and tuned on 808 $12P without the blower, then he blew his T5, replaced with a T56 and put the blower on. almost ready to come back and get boost tuned, and then one of his mates told him he will get more horsepower with a haltech driving it so he bought a haltech and took it to another tuner locally and got it dyno tuned from scratch. tuned it up to 430hp atw but the tuner was a bit worried when he found out it only had the 2 bolt mains so limited it to 6k and 400hp.


anyway my mate said its the most fun car hes ever driven boosted 355 ftw.

[Holden202T]

nice! what manifold is that running ? i guess if something like that was put on my brothers motor it could retain the maf and probably make life alot easier all round!

[Jayme]

looks a lot like a come racing twin throttle manifold to me.

[shane1]

Its a come racing one , definately not the greatest manifold, a harrop with a 4 barrel throttle body is a lot more even as far as cyl distributtion goes , but the come one is a lot easier to work with.

[Jayme]

yeah I agree there! the only car I ever tuned with a come racing manifold (the above mentioned 355) I had to put a massive spike in the VE table between 1600 and 1800 rpm to stop it leaning out, and the narrowband which was in the front two cylinders seemed to read a fair bit different to the wideband which was on all 4.