fc3sfreek

iTrader: (6)

i was just wondering how much boost can a stock s4 turbo handle? i tried searching but didnt find anything about it.

FC3S.USD

iTrader: (2)

12- 13 psi would be max safe. but thats only when you have upgraded some other items.

fc3sfreek

iTrader: (6)

other items like what? exhaust ,intake, etc.? yea im new to TII's so i dont kno much about them

Sideways7

iTrader: (7)

One of the most important things when raising the boost on any car, especially a rotary, is fuel. You will need to get at least an S-AFC or somthing similar to adjust the fuel levels. It would prob. be a good idea to get a larger fuel pump (Walbro 255 is popular) just to be safe. Theres other people that can tell you specifics, but thats a start.

fc3sfreek

iTrader: (6)

ok because i was looking at electronic boost controllers and wondering how much i can tune it to without blowing anything. i have a friend that has one of these boost controllers and doesnt have anything w/ the fuel system upgraded. and he can turn his boost up to 14.5. but then again thats a VW GTI.

Sideways7

iTrader: (7)

Exactly. Rotaries are very succeptable to detonation. In fact, all it takes is one good ping to pop an apex seal. You need to be careful with all cars, but especially with rotaries.

88 GTU

good somebody brought this topic up i'm doing a turbo-n/a and useing the stock s4 turbo and injectors so i was gonna ask this question too

pinkfloyd

a larger IC like a front mount would help but there are a few people on here still using the top mount at 13psi. One guy tested his intake temps before and after the IC both on the top mount and when he went front mount, now i dont remember the #'s but the front mount droped the temps down a great deal.

88 gtu, from what i have read 8 psi is the normal max when turbing an na, although there is a guy on here that says he has been boosting 10psi with no problems for over a year, just make sure you have a wide band or soemthign to make sure your not leaning out.

other then that just listen to what other people said, more fuel, better IC, and something to kinda tune it with.

ddub

It's not necessarily just "these cars" it's just the fact the fuel system is limited. The golf probably just has more fuel and is more expandable, older cars don't seem to have this luxury as much from what I've seen. I mean, you still tune a turbo rotary to the same a/f ratios as a turbo piston, it's really not as different as you're making it out to seem.

Anyways, 12-13 psi is about the max the stock turbo should go to without becoming inefficient, but I've heard that the stock intercooler isn't that great past 10psi, though some people do push past this. To be safe I think you should get some upgraded secondary injectors, s-afc to tune it with a wideband either on the dyno or one you buy yourself (otherwise how are you going to tune), and upgraded fuel pump with a fuel pump rewire.

JamesWade2002

ok, so if the car has an airflow meter then the computer is gonna read how much air the engine is taking in and then run the injectors to the curve that is determined by the ecu in conjunction with readings from the AFM. So why would you wanna make it run richer with an S-AFC if the stock ECU is gonna run the injectors to 100% duty cycle, if it has to, to keep up with the AFM. The real truth is this person needs all of the above at the same time or he is waisting his time. an S-AFC on a stock fuel system is only good for leaning the engine out.

How the hell would I know, I don't even have a turbo car??!!!??WTF???!

Dude, you'll need to port your stock wastegate, get larger secondary injectors, either an FD pump or a walbro, somthing to meter the fuel supply cause with the stock map and more fuel, you'll run rich somewhere which will KILL your power. Do all of this BEFORE you do your exhaust, run some good vac hose to the wastegate actuator and the fpr. I don't know about the intercooler cause I don't know at what point the compressor side starts to heat the air up enough to create detonation with the engine tuned to 12.0:1 or what ever your dyno man says. All of this stuff will change when you use a larger turbo. Don't think of boost as stages or performance. Boost is a measure of restriction. Think, how much fuel will I need to maintain mixture ratio A while generating XXX amount of horsepower, while keeping EGTs below some detonation threshold. I want my car to put out about 1500-1600 degree EGT, but I am an N/A dude for now, we don't do detonation before something like 28 degrees past TDC.

Rex4Life

I've been running up in the 12-14 psi range and have not have any problems (almost a year now). I get on the car pretty hard as often as I can. Most likely two big upgrades have kept me out of trouble:

1) Rtek 1.7 with 720's (ehh and the other fuel mods too)

and

2) FMIC--the Porcshe front mount is doing a real good job.

HTH,

Scott

88rxn/a

iTrader: (6)

for people doing a n/a turbo: shold we need a aftermarket fpr?? if so how about a tII fpr?? or can we stick with the stock one???

bingoboy

quite a few people have found that over 15psi and the turbo likes to eat itself. not an efficiency thing, more of a stock turbo can't handle it thing.

JamesWade2002

why would you wanna bring your FPR up at the rail if you have larger injectors and some way to tune the ECU's fuel curve and a pump that will supply them. If you turn it up on stock stuff, you'll run rich somewhere. If you have custom ECU or some sort of controller, then just tune it right. Use the MAF or get a Haltech.

RX_AV8TR

Okay, I know I'm the new guy here but here's what you need to do if you're planning on turning that boost ****...

Boost gage (of course)
EGT
Fuel Pressure Gage
HAL meter with fuel injector cycle
Retard the ingition about 2 deg
Seal the vacuum line to the fuel pressure regulator

Those gages will tell you exactly how much boost your engine can handle. Then you will be ready to crank up the boost and upgrade your car and tune it and know when to let off the gas before killing your engine

J-Rat

iTrader: (2)

wow...

For what its worth, I ran my stock HT-18 in excess of 15 pounds ON the stock Intercooler with a stock motor and was bagging 13s all day long with just bigger injectors and an SAFC. Is this what I suggest you do? No, but I thought I would let you know that the stocker can make some more boost.

slpin

iTrader: (9)

yesterday at the track
about 110 degrees

i trapped the same at .5 bar and .8 bar
and i have enough fuel to support it
soooo, make your judgement...