SpeedOfLife

iTrader: (16)

'87 TII, stock configuration except for emissions/air pump removal, straight downpipe for now, RB FCD, and I ported the wastegate out as much as I can with the stock turbo hot side. Now, the last time the car was running I couldn't boost past ~2psi, usually limited to ~1psi. I have compression, I think either the wastegate or bov got stuck open at the last autocross meet. Can I fix the existing parts if they're broken, how might I test the wg actuator and bov, and do I absolutely need to do anything else to keep my motor reasonably safe?

I'm trying to prepare for an autocross meet this weekend, but I don't think I'll have the time to install exhaust between my dp and 'stock' y-pipe, so I was wondering if I could run with just the dp.

SpeedOfLife

iTrader: (16)

Someone has suggested pulling the FCD if I'm going to make an attempt at autocross since my car would only dump fuel for the boost at which the FCD fools the ECU... maybe a RB FCD boost map would be appropriate. Anyone?

markdman

check for a vacuum leak in the acctuator hose. im sure you didnt, but check and be sure you didnt port the wastegate hole bigger then the flapper.

i use a hand held vacuum pump ($50 from shucks) to test my `gates and `valves

straight pipe *should* make you spool quicker thus build boost sooner.

as for safe? keep it rich

SpeedOfLife

iTrader: (16)

I'll check for leaks like you said, and yeah I've been careful not to port it out big enough to let much air escape, as well as making sure the flapper can't get stuck.

How am I supposed to keep it rich though? I don't have an SAFC of any sort...

MaczPayne

iTrader: (5)

You need a way to control fuel delivery. There are no exceptions.

SpeedOfLife

iTrader: (16)

Well then my question is 'how?'

What about putting 720cc injectors in for the secondaries? I know the stock ECU won't know what to do with it, but at least it'll be richer than normal...

Maybe I'll just see if I can pick up a fuel control unit this week. Man, that sucks. Any other suggestions/ideas?

MaczPayne

iTrader: (5)

go with the 720's if that's all you can do. It'll run rich but that's better than having it run lean.

Digi7ech

iTrader: (1)

The BOV being stuck open. You'd have a huge vac leak if it were open unless it's under boost only. A ghetto way to check would be to tape over the BOV exhaust vents to block it. If they are ripped out after boosting and gradually letting off boost(to not activate it) then the BOV is bad.

Wastegate being open woudl be from breaking the flap arm or not securing it back onto the actuator. Check to make sure the arm is still on the actiator and held on by a C clip.

Also pull the actuator bar to see how tough it is to make the wastegate open. It's pretty tough so if it moves freely then maybe you broke the actuator spring.
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To make your car reliable. You need to control boost and have enough fuel to go over your desired Psi as a safety net.

Once you get the boost issue fixed. I'd say go for 8 psi to make sure it's ok and then go 10 after you do fuel mods.
Fuel pump and 720CC injectors with Rtek 1.7 will give you a great buffer zone while improving your ECU issue(FCD's are terrible)

SpeedOfLife

iTrader: (16)

yeah the c clip was still attached fine.
it's also pretty hard to move the actuator arm.

also, for now I just want it to boost normally, up to ~8 psi or whatever the stock limit was. I'm not looking for any serious power right now, it'll need a rebuild first. so what I'm hoping is that I can finally get it to boost properly, but not creep.

I'm still not certain where I should connect my boost sensor now that the stock location will be blocked off. I haven't looked hard at the lines, but I'm fairly certain I wouldn't know exactly where to connect it, plus I don't own a vacuum/boost gauge.

Digi7ech

iTrader: (1)

As a note.

I am running
Walbro Fuel pump
Aeromotive FPR set to 38psi at atmosperic with 1 to 1 psi increase.
550 primaries
720 secondaries
Rtek 1.7
Ported wastegate
RB 2.5 downpipe to silencer
3inch CS catback

I run 10psi daily. I accidentally blew off my wastegate line 3 weeks ago and didn't catch it till I was at work. My motor is still alive because I had a safety net so when my motor hit 15psi it was still ok.

You try that on 550cc injectors and your motor will most likely be toast.

The Rtek will remove the Fuel cut while helping timing and using bigger injectors.
It's totally worth it for a relatively stock S4.

///
My boost sensor is teed off with my BOV and boost gauge from the UIM nipple.
GET a Boost/VAC gauge ASAP! It's worth it's weight in gold on turbo cars.

SpeedOfLife

iTrader: (16)

I'd consider the RTEK if I wasn't sure I would eventually go standalone. That's the 'end in sight' for me. Eventually I want to go crazy for maybe a streetable 350+hp, but right now I'd just like to get around 200hp. nothing crazy, just a light improvement on the stock power (as well as getting the bugger to idle...).

I'm just trying to get to slightly higher than stock power for as little cost as possible.

SpeedOfLife

iTrader: (16)

I was thinking about teeing the lines... might as well, it'd keep it simple.

I think I've heard you can adjust the boost limit with the stock setup, if so, how? If anything I'd just want to check what it's set to and keep it at or below 8psi, depending on if I can make it creep or not.

Also, I'm curious about your wastegate port, did you port it out to the size of the stock flapper or did you make it huge and weld a bigger flapper door?

Digi7ech

iTrader: (1)

I ported it to the edges of the stock flap and actually side cut some of it so it's a little open as is. I then ground some of the back of the flap and the back plate off to give it a bit more room to open.

I don't creep until I'm in 5th gear at WOT.

FCD's are crap. They trick the ecu into thinking your at a lower boost so timing isn't at it's correct spot. Rtek removes that while giving timing retard and complete removal of FCD.

Even if you go standalone later you can sell the rtek for cash.

SpeedOfLife

iTrader: (16)

Here's what I've done for the wastegate, sorry for the crappy pics, I did what I could. I did the same thing with the top of the flapper as well as grinding down the turbo cover a little.



Does the stock ECU adjust timing then under boost? If so, maybe I would be better off forgetting about the FCD...

SpeedOfLife

iTrader: (16)

any input on my port job?

I'm hoping it'll work decent...

Digi7ech

iTrader: (1)

I've never ported a S4 wastegate but I think you may still experience boost creep.

SpeedOfLife

iTrader: (16)

yeah it wouldn't surprise me, but there's really only one way to find out for sure.

I can always make the hole bigger, I just don't want to make it impossible to build boost in the first place so I'll start at this point.

imloggedin

just take out the BOV and see if you build more boost if you want to eliminate that problem. you can run it without the BOV with no ill effect unless the turbo has problems already (everyone who thinks you are in dire need of a BOV can save the speech). use a manual boost controller to bring up the boost a little. make sure you watch the creep on a real boost gauge, not the stock one. you dont need 720's to make 8psi.

on the cheap you could buy an SAFC to control your fuel. id have a wideband before i changed anything though. youre looking at more $ and time than you probably wanna spend though.

downpipes gonna be louuud

imloggedin

also if your bov is stuck open somehow, it will not feel good on your turbo so you should check that sooooon.

Digi7ech

iTrader: (1)

On a S5 unported wastegate with 2.5 downpipe and presilencer to 3 inch CS singel catback I would creep up to 10psi.

I'd say that the S4 wastegate ported like above would only be equal to one of the unported S5 holes.

I thin you should port it to the very edges of the flappers cover. Maybe even a little more but remember to make sure it's enough so that the flap can't get stuck in the hole.

If iover ported you may lose a bit of top end psi and a slightly slower spool but I think it's a worthy trade off compared to unchecked boost spikes.

SpeedOfLife

iTrader: (16)

how do you mean? it will hurt the turbo or I'll feel the effects while driving?

and I know fully well it'll be loud . it'd be fun for a few days, and then I'd need to keep my hearing and stay out of trouble with the cops...

SpeedOfLife

iTrader: (16)

maybe I should. I know the recommended best way is to make the port HUGE and weld a washer in, but I don't have the time or a welder. I also have a test tomorrow night... Maybe I'll go ahead and make an extra slot for air flow outside the stock flapper to be safe (I'd do it anyway if I tested it and found I'm creeping, but you guys are probably right that I'm likely to creep as it is...).

imloggedin

i mean think of what happens when your turbo is trying to create boost and the wastegate sees 0psi while the turbo is working its little bearing off trying to make boost, and failing as it goes to atmosphere.



eeeeeee

SpeedOfLife

iTrader: (16)

well I'd lack extra intake pressure, but it shouldn't spool the turbo past its limits, right?

btw I picked up some vac lines, plugs, tees, and a vac/pressure gauge tonight so I can finish this SOB! ...still need my blockoff plates, but hopefully they'll come tomorrow.

SpeedOfLife

iTrader: (16)

I forgot to ask, I bought some grade 8 bolts to replace the hot side and exit flange bolts, will grade 8 hold up to the heat? I got them because most of the old ones are bent and the flange bolts both broke on the way out (and yes, I got the rest out, the hot side is good to go).