Hi

quick question as i couldn't find it in searching then again i suck at searching so feel free to flame me if it's in around this forum.



I have a s5 turbo II it has a newly rebuilt engine with a decent sized extended port( my engine builder said it would have around 270ish flywheel horsepower, perhaps he was being generous) and right about to purchase a Racing beat turbo back system. I do have plans for running a haltec, and 550prims/1600second a bit later(after I ready to purchase a t04 of some flavor) on but for right now the only mods will be the extend port and the turbo back. So my question being is can i run this set up safely stock of with just a walbro 255 and a 12:1 fmu? because realistically I don't want to have to buy a safc or something when the haltec will be purchased within 2 months time. Also this engine is still in the break ni period perhaps I'm getting ahead of myself by even thinking about changing the exhaust system yet?



thanks for your answers in advance

Kevin

i would bypass the boost solenoid, ie lower the boost as much as you can. you're prolly ok until about 10psi with a setup like that, so id just keep my foot out of it

with a port you will flow more air at the same psi , so you will eb leaner then the stock map isused for, and i wouldnt trust the afm to do any corrections for this. so just drive like a turtle untill u get it tuned

well it's a damn good deal on the exhuast but your right now reason to mess up the ass load of money i just had to put into the car I'll leave the exhuast in my garage for a bit until she's been well and broken in and ready for the fuel mods and microtech tuning (i've switched becuase I found out there is a microtech tuner in mcihigan and the though of tuning by myself and having to by a wide bind kinda scares me. thanks for the adive i guess i already new what the answer should have been.

You must be in FD mode. The FC uses an AFM, not speed density like the FD. While the AFM is a unneeded restriction in the intake, it adapts to modifications with much greater versitality than a MAP based car.

even the afm cars run wierd in the midrange cause the closed loop cant compensate for the additional airflow.



on a couple of cars ive doen you can feel the o2 cycle, it goes rich, then lean, and it bucks and then goes rich again

I ran a cone filter, 3'' thunderfabrications dp/mp, n1 single with a walbro/fcd and put down 232 rwhp at 11 pounds. The airfuel ratio's were mid 11's to redline https://www.nopistons.com/forums/pub...1047683329.gif https://www.nopistons.com/forums/pub...IR#>/bigok.gif



edit - I have noticed a slight lean hump on several FC dyno's, curiously enough this was after the secondary injectors were firing. I dismissed it though due to stock fuel pump/poor voltage/clogged filter etc... https://www.nopistons.com/forums/pub...1047683561.gif

http://dramon.nopistons.com/gallery/...h_baseline.jpgMy dyno graph.



Bone stock, 8 psi



no p/s, a/c or emissions.

My car you can feel a small dump in power at about 5

stick a dirty air filter and keep the stock air box. that should help