safe boost level T28 50 trim

Hey everyone. I was wondering where I should set my boost. Right now it is only at 15psi. I will soon be done installing my fmic from that group buy and I plan on turning it up. I was going to put it around 17psi but, I have heard it would be good up to 20psi safely. All my info is in my sig. Oh and I do have 650cc injectors but, they are NOT installed yet. I do have a fuel pump though. Any input would be awesome thanks.

You might it fuel cut without the injectors in. Try it out and see what happens worst case senerio you just turn it down a bit, I was running 18psi on stock injectors and I hit fuel cut really easily (5500-6k rpms)

Your 650 injectors are just fine for the amount of boost you plan on running. The install is not that bad at all, but I would reccomend getting the upgraded lower seals for the injectors regardless. At 20psi knock will be your biggest concern, make sure you get a logger and keep the knock down. You wont hit fuel cut, just get a good tune and you should be good to go.

If i was you i would invest in getting DSMLINK!!!!! I paid $605 for my ecu to get done and im just waiting to install it when i get my car back together.

I have a friend that has his evo16g set at 19psi witout fuel-cut. IIRC it happens around 2.5g/rev on the stock fuel system.

stock injectors? I'd say keep it around 12-13. What's the point of potentially starving your motor of fuel? The 50 trim flows ALOT of air way too much for the stock injectors to handle.

Yeah man, I would for sure keep it to 12-13 like crunchy said. Remember you will need DSMlink to control those 660's. Also, the t-28 isnt a 50 trim is it?

Thanks everyone. Right now I am going to just keep my boost set at 15psi. I am waiting to get a fuel pressure regulator to install my injectors so I can adjust my a/f with the safc. After I install the FPR and injectors I will probably turn it up to 20psi. I already have a palm pilot with the logging software(just need to download it). Thanks again for the help.

I can just use my SAFC for the 650cc can't I? And as for the turbo... the guy before me said the t25 was replaced with the engine/tranny rebuild. Funny enough he had no idea what the turbo was but, he was positive it has 50 trim installed. I posted some threads about helping me figure out what it is and as far as I found out and from what other people said it is a T28. The turbo is a Garrett/Mitsu turbo. If you want pictures here is a link http://www.cardomain.com/ride/839636/3 scroll to the bottom.

It looks like a T-28 to me, But one thing i wonder is can you run 660cc on a SAFC? You need DSMLINK i believe. Maybe not with 660cc im not sure. Im going with 880cc or higher since i just got my DSMLINK :)

660's are pushing the SAFC. They cant tune that well past like 550s, 650s can get a runable tune, and anything past that is impossible. I would sell your pocketlogger and SAFC and put it towards DSM link. You could probably make it work ok on the SAFC, but you will have trouble tuning to the setups full potential.

Okay, that is what I thought. I think as of now I will just use the pocket logger and the safc to tune it as good as I can. I will edventually end up getting DSM link though, but right now it is a bit more money than I have.

I have a friend that has his evo16g set at 19psi witout fuel-cut. IIRC it happens around 2.5g/rev on the stock fuel system.
It was pretty cold hear at the time so that's probably why i hit it at 18psi.

The T28 and the 50trim turbo are very different. Which one do you have? The T28 looks exactly like the stock T25, but has a bigger compressor wheel. The 50trim is obviously bigger and capable of pushing alot more air. 660s are nearly impossible to tune with a SAFC2. You will need DSMLink or emanage or an AEM unit

Remember that the trim of the turbo is not the size, just the ratio of some of the dimensions. You could have a very small wheel like a t28 be a 50 trim, just not "the" 50 trim :D

At any rate, the t28 is somewhere around the size of a 14b. I think the highest airflow I heard logged was something like 32-34 lbs. So you could treat it as such. 20 psi should be doable. I would just keep raising boost until it knocks or stops increasing in peak airflow.

Well last night I finished it up and took a run. I had it set at 15psi. It had no problem no fuel cut or anything. BUT, today I took it for a run and I was accelerating through 2nd. It hit full boost then at about 6K I heard a loud pop and the car jerked then kept going. I did this one more time and it would jerk after about 5.5k. I figured this was fuel cut off so I turnt it down to about 13psi. It runs fine now. Only thing that I am puzzled about is that it did not hit fuel cut off last night. It was colder last night than it is today. I am just wondering why I didn't hit fuel cut off last night but, I did today. I thought maybe a blew a coupler so I checked and couldn't find any signs of slipping. I will build a boost leak tester asap but, untill then my boost will stay at 13.

Did the injectors get installed and the appropriate adjustments made to the AFC?

I did not install the injectors yet. I am still running the stock injectors. I am waiting on an fpr to install the injectors.

cant the stock head gaskets only take 23 psi... which is really really pushing it. id be safe and install some arp head bolts if i was you. thats what im doing until i swap my motor next winter for a 6bolt stroker :grinyes:

It already has the arp head bolts in it. I looked at the bill for the motor rebuild and saw that the bolts they put on were about 100 bucks. So I looked up the part number and all and it is the ARP head bolts.

So there's no real surprise it hit fuel cut, since the airflow signal hasn't been chopped down yet.

You can never never measure the strength of a headgasket in PSI. PSI is pretty meaningless. Cylinder pressure is the value that is going have a limit for a given gasket and a given set of circumstances. ;) I ran a stock headgasket with ARP studs into the low 11s, others have run low 10s on them, which requires 30 plus psi, even on strokers, for a point of reference.

Okay, well when I hit fuel cut a black puff of smoke came out of my exhaust. Is this normal with fuel cut off? I thought black smoke means you are running rich? There was also a pop when this happened(maybe backfire or coupler?) Well I am now thinking that maybe a coupler slid off when I hit full boost causing my car to temperarily run rich. Because the kit came short of 2 t-bolt clamps I had to use 2 worm clamps instead. The coupler that I think would have slid loose I put an extra clamp on. I think tommarow I will play with it a little bit and see if it was the coupler or not. I want to build a boost leak tester but, I do not have the supplies right now. But, is black smoke common when you hit fuel cut? Like I said I took it for a test drive when I first got done and it was a really cold night but, I ran 15psi no problem.

So, is a puff of black smoke and a backfire/pop common for fuel cut?

Never saw my car hit fuel cut from the back :D Not sure, but it wouldn't be unlikely. I would ASSume it is, since you haven't done anything to prevent it yet, and it goes away at lower boost. If once you do the injectors and AFC you find it still does this, then I would be worried.

Damn, that just intensifies my excitement for my income tax refund money which is buying my a fpr. I want to start some tuning but, it all is waiting on a damn fpr. I am dling my software and all to my comp and pocket logger sometime this week and I will play with it untill I get my FPR so I will already be familiar with it. I will let you all know how it goes.

Does fuel cut actually cut fuel or spark? I'd think it cuts spark (if it cut fuel then it'd get too lean) If it cut spark then it would puff some smoke and possibly backfire.

Makes sense.