ok i tried searching but couldn't find anything. just got my car running nd the vcum to boost transition is very bad i have 440's at 25 psi.it hesitates real bad going into boost. and i don't know what could be the problem any help would be great. thanks in advance

What are you using to prevent your MAP from seeing boost?

lower your fuel pressure to 20psi.

missing link. and when i hd it set to around 20 psii just wanted to die out and it had a real bad idle. i also have a dis-2.

whats your vac at idle reading and whats your fuel setup?

my vacum is at 18-16 at idle. and my fuel setup is a 255 walbro fuel pump, sfmu set up for 440's.

Mine is really bad if I just floor it while cruising at 3k or above. I have to get on it gently until a few pounds of boost then I can floor it, I guess its because the boost hits faster than than the fuel, it just kinda hesitates and the exhaust pops... You just have to deal with it I guess... one of the many limitations of using the sfmu...

well that's just something i don'twant to have to just deal with! there has to be some type of solution to this. besides a ms or 8-injector setup. someone please help!!

Well you'll never get rid of it, thats why hahn advertises a seemless transistion into boost with the portfueler... but maybe someone will give you some tips, I don't know of any, sorry.

i thought there was some vaccume restricter thing for the sfmu that helped stop that?? i dunno i just heard that i dont have any experience with it

Originally posted by CarbonFiberRST
Mine is really bad if I just floor it while cruising at 3k or above. I have to get on it gently until a few pounds of boost then I can floor it, I guess its because the boost hits faster than than the fuel, it just kinda hesitates and the exhaust pops... You just have to deal with it I guess... one of the many limitations of using the sfmu...

This is the same problem I'm having w/ no solution to the problem on the post I made. The reason it's doing that is because your running real rich at 0 psi, BEFORE the turbo boosts. So it's backfiring from the unspent fuel outside of the exhaust ports. I didn't get a restrictor w/ my sfmu, so I'm going to splice in a welding tip which will probably help.

I got a restrictor but I didn't install it, whats the proper way? small end toward vac source? That is what someone posted but it makes more sense imo to have the big end toward the source so the air can have a smooth transition inside the restrictor instead of the air hitting the blunt side of it and then haveing to go through the small hole... i dunno.

I would think that it really doesn't matter, it'll just change the distance the small orfice is away from the sfmu.

A different FPR restrictor won't do anything to help the shady vacuum/boost transition that some people have. Sometimes a Missing Link can fix the problem, and sometimes a simple voltage clamp like the adjustable Shit Shack 3 wire unit or the HRC/STAR 2 wire unit will work. I needed both in order for my car to be somewhat drivable, but it wasn't perfectly smooth until I built an ECU which can actually deal with boost pressure.

I don't have any restrictor though. I'm sure Vortech includes them for a reason (which I didn't get because I bought my sfmu used). It might lag the sfmu long enough for the turbo to already be spooled.

well thanksguys for the info i guess ill just call vortech nd see if i can order one of those restirictos and see if that helps. thanks again.

Make your own electronic one (The site is here somewhere) I had the ML and I had the same problem (among others) After I built that thing no more ruff transition. I had mine set for about 4.5v if I remeber correctly. (BTW a monkey could make one!)

I think someone here said you can use a welding tip for a restrictor
Alvin

http://www.cardomain.com/id/96rst

Originally posted by Semperboost
I think someone here said you can use a welding tip for a restrictor Alvin http://www.cardomain.com/id/96rst

Yeah, that's what I'm doing. I'm going to notch it so that it can be securely held.

Originally posted by Pyscodragon
(BTW a monkey could make one!)

hmm i think i know that monkey :P