AFPR for reliability w/ minor mods?

DSMRook · Apr 30, 2009

Ok, so I've been looking around for a few answers and it's been hard to pinpoint exactly what I should do, considering everyone always has something different to say.

I just bought a 91 Talson TSi AWD with some mods. 190lph Walbro and 2g injectors being the most noticeable. The rest of the mods can be seen.

I do hit 10psi at or around 3rpm however as soon as I get to 4500rpm I see 15psi then closing in on 20psi. Now, I'm not new to the turbo world and I'm assuming the large 3in exhaust might be a little much. I disconnected my wastegate actuator and sure enough once I hit 4500rpm I get 17psi. So I concluded I need to get my turbo ported. I'm not too worried about that since I know I do have a pump and injectors. However, the previous owner did have an AFPR and removed it before the sell.

I've hit fuel cut a couple times when she get's up there in the rpm, above 6k. I'm curious as to an AFPR will help ensure that my fuel pressure stays at a constant 1:1 ratio with my boost. I'm looking for reliablity here with these mods considering I'm one of those broke college students looking for some fun. Try not to rag too bad haha, I'm new to the forum! Thanks!

Calan · Apr 30, 2009

We need more info on your car (like which turbo, etc), but I would say the AFPR should be a ways down on your priority list.

Depending on what you've left out in your profile, I'd say get a logger and get a good tune on it first. Figure out what your injector IDC's are and where you're at AFR-wise. You may need more fuel pump, bigger injectors, or any one of several other things... but with that Wally 190, an AFPR probably isn't one of them right now.

91tizzy · Apr 30, 2009

just invest or borrow a fuel pressure gauge and get the reading off the fuel filter....if everything fuel pressure wise is to spec (37psi with the vacuum line removed) then you do not need a afpr. Only if you are having fuel overrun(more than 37 psi) issues would I suggest getting one.

BTW dont ever disconnect you wastegate actuator again.....hope i misread that, you will have an infinite boost situation and if you keep your foot in it the weak link in your engine will be found in a very short amount of time. And the "boost creep" you are seeing is undoubtedly from the 3 inch exhaust. my 2.5 inch turbo back allows me to creep a good amount let alone a 3 inch.

Drubble · Apr 30, 2009

As was said, put the actuator back on. Do you have a manual boost controller? If not, better get one.

DSMRook · Apr 30, 2009

Yeah the actuator is back on, i only did one run in 3rd gear to check boost levels. As far as I'm concerned the turbo is the stock 14b. I don't have a MBC yet because that wont lower my boost levels at all.

91tizzy - How would my wastegate being open 100% give me infinite boost? As far as I'm concerned, if it were shut that's when I would run into "infinite boost" problems.

I read more into the capability of the 14b turbo and was considering purchasing 16g hot side housing seeing that the 7cm^2 would benefit me more. But I think it'd be a good idea to purchase a logger and check what's going on first before I do any further mods.;

dsmfa9nutter · Apr 30, 2009

You need to start at the bottom. Do not start throwing bigger turbo's on before you even have a mbc and logger.

PIMking · Apr 30, 2009

well your 2g injectors for one are the same size as the 1g's..

91tizzy · May 1, 2009

DSMRook said:
Yeah the actuator is back on, i only did one run in 3rd gear to check boost levels. As far as I'm concerned the turbo is the stock 14b. I don't have a MBC yet because that wont lower my boost levels at all.

91tizzy - How would my wastegate being open 100% give me infinite boost? As far as I'm concerned, if it were shut that's when I would run into "infinite boost" problems.

I read more into the capability of the 14b turbo and was considering purchasing 16g hot side housing seeing that the 7cm^2 would benefit me more. But I think it'd be a good idea to purchase a logger and check what's going on first before I do any further mods.;

ah I was under the assumption you ran no pressure signal line to the actuator and went romping on it. :ohdamn:

The 7cm^2 does wake a 14b up.

edit: so your saying you had 17psi in third gear with the wastegate open? How is that possible?

DSMRook · May 1, 2009

Yeah. The purpose of taking the actuator off was to see is the wastegate was frozen. After finding out that it wasn't, I wanted to make sure it was able to open all the way up. Once I hit 4500rpm the boost climbs from 10 (take forever to even get there but is does) peaking near 17 or 18 progressively as the rpms climb.

I don't know if the wastegate needs to be ported, but if that was the case I was going to replace the housing like stated before. That and, I still have the stock O2 housing aswell.

-edit So basically, I'm thinking my wastegate isn't efficient enough for the lack of pressure due to my 3 inch exhaust

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AFPR for reliability w/ minor mods?

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