DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

Ok This post may get long if so I am sorry I have tried to figure these problems out it has been posted by Pep for me with no prevail.

here is more about SOME problems
https://www.homemadeturbo.com/forum/...;threadid=8333

Here is my HORRIBLE setup I have a 1991 crx with a DOHC ZC DX transmission Ram clutch Ghettodyne ECU 450's t25 HF mani and adapter plate 2-1/4 exaust down to the converter (here is where it gets REAL GHETTO) out the converter 2" exaust to the resignator then drop even more in size to the muffler.. I have a feeling this is stopping my turbo from spooling well... 7-8 psi boost btw. I will be adding pics shortly. My charge pipe is mandrel bent 2" (kind of long though)

charge pipes
http://www.thezcresource.com/modules...view_photo.php
turbo
http://www.thezcresource.com/modules...view_photo.php

BOV
http://www.thezcresource.com/modules...view_photo.php

First Problem. I came against a 1990 crx SI with a Zdyne silver and a d16a6 and he took me from launch (launch controll set at 3,000) untill third (my new clutch broke loose and spun when i shifted to second) he damn near took me when i got third i pulled on him for a win at 80mph (no time slips the track was not giving them that day) this car should be WAY faster

Second Problem Its a BITCH to get to full boost I have checked the wastegate its working I checked the BOV it is working right to. Is this also because of the exaust? I am going to be hacking the exaust off after the converter this week.

Third problem Surgeing idle... I cleaned the EAVC and all that happy jaz. I keep getting a O2 code even though I replaced it twice and cleared the codes(damn autozone shyt).

My solutions so far are.
I am rotating my turbo and adding a smic this week that will get the pipes away from the hot manifold. I am cutting the exaust off at the back of the converter and adding a supertrapp muffler (I will worry abou e check when its time) and replaceing the darned 02 sensor again.. Any other ideas? I really need to work this out. I do see a exaust leak before the turbo there too

Re:DOHC ZC t25 advise please Dr.Boost, someone?
 

looks like that chargepipe is collecting heat from the exhaust manifold... and yes, 2" exhaust or smaller will hurt your hp output pretty good. I had a 2" pacesetter exhaust with a stock res. on and tested it first, then cut it off and tested again and the spool up was much better. 2.5+ inch seems to be a good idea.

Re:DOHC ZC t25 advise please Dr.Boost, someone?
 

OH, and another thing man... I also had a similar leak on my manifold exactly how yours looks. The HF manifold as a small little lip right there you can fill in with a welder and grind out flat with an angle grinder. I did that, made if flat and made a new gasket and no leaks at all. It's also a good idea to get the engine up to normal temperatures (go drive it) and then tighten down the bolts a little more when they're nice and hot.

Re:DOHC ZC t25 advise please Dr.Boost, someone?
 

The exhaust leak is what is causing the lag in boost. Even a tiny leak will drop your psi and lag the turbo.

I think after you hack the exhaust off, fix the leak, and get the charge pipes away from the heat you will be ok.

Let us know what happens.
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Re:DOHC ZC t25 advise please Dr.Boost, someone?
 

Kool guys thanks I will be reworking it tomarrow. Then I will do it again when the intercooler comes in. I will get all of that fix by tuesday most likely. I will keep you guys posted though

Re:DOHC ZC t25 advise please Dr.Boost, someone?
 

ok update I found a few problems that are taking longer then i though to fix. My flange warped for the exaust. I made some gaskets to seal it up better. I changed my charge pipes because i could NOT turn the turbo the other way. So now my charge pipes run thru the bumper past where the battery USED to be key words USED to be. Moved the battery to the trunk. Its way loud with just a cat converter on it so i have to put the OLD exaust back on till next week. I am getting a SMIC I will mount it where the battery used to be! It should be alot better I have to ditch that exause yet still. I NEED a t25 O2 housing bad so i can make a better downpipe. I noticed some oil in the air tubes the ones that go to the intake so either my oil line return is to crimped or I need to drop the presure. It doesnt smoke though not at all. I think I am getting there for working on my daily driver lol...

Re:DOHC ZC t25 advise please Dr.Boost, someone?
 

are you using the HF manifold for the o2 location?

Re:DOHC ZC t25 advise please Dr.Boost, someone?
 

yea i am but i need it to use it as a flange

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

Ok Here we go. I changed it all moved the charge pipes they run thru the FRONT of the car behind the bumper. Put the battery in the hatch to make room for the smic i will be getting soon. Exaust is now all 2-1/4 with a supertrapp at the end running 7 disks. Exaust stops about where the resinator would commonly be.

here is the pics of the Charge pipes the new way.
http://www.thezcr.com/modules.php?se...view_photo.php

http://www.thezcr.com/modules.php?se...view_photo.php

http://www.thezcr.com/modules.php?se...view_photo.php

http://www.thezcr.com/modules.php?se...view_photo.php

http://www.thezcr.com/modules.php?se...view_photo.php

http://www.thezcr.com/modules.php?se...view_photo.php


I am running about 9psi. It spools up ok to about 5psi. by 5,000rpm its chopping up BAD.... this is usually at partial throttle. I swear it sounds like fuel cut.

Any ideas whats going on with it now? I am going to try to turn down the boost again.. I think the t25 is to small for the demand I want. Since I got my ticket >:( I have to find a SAFE PLACE ::) to open it up and see what it does. :P

My opinion so far is... The car is to damn loud lol. The turbo spools up better but It is having a hard time reaching 9psi and I think the wastegate is sticking...

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

it looks as though your pipes are already nicely setup for a FMIC :)

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

yea if i could afford one i just sent the $$$ out for a smic i could always make it a small fmic lol... I just took it out again and my wastegate isnt working at ALL i think fixing that may help. I put somewashers behind it to make it in a better location and i bet it is out of range time to get a vac/press thing and pump it up and set it right lol.

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

Are you sure you're getting enough fuel? I would try going a bit richer on the fuel maps and see what happens.
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Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

I had te same problem on my civic, where it felt like is was not geting fuel. I bumped up the fuel, still did it. Somebody emailed me and said to bump down the fuel , I did, not i runs perfect, no more boost problems.

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

hrm i can hold it part throttle at 5 psi and it holds to about 6,000 rpm. I cant get enough speed to keep 9psi around here with all the cops but when i got close it SLOWLY drew Up to 9and started screwing up again. I cant see my a/f gauge to see what it is doing I am going to have to move it. I am problebly getting a t3 soon not sure what size till it gets here.


Trouble shooting is a pain!!

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

Ok I think I can descripe it better!!!! :o

I was just driving tonight its kinda cool out. Car was about warmed up so I figured ah heck lets get into boost... :) Out of the blue at around 6,000 rpm unknow boost It SOUNDED blurpy like the rev limiters do and jerked me back into my seat!!! I still cant see my af gauge but i looked right after it happened and i WAS on the rich side. (i have 4 bars for rich I was in 2) My Vac boost gauge is hooked into my FPR and my wastegate is hooked to my dashpot. I also noticed that during ANY vacume my BOV is open... (makes it hard to build boost that way dont it?) So here I go again. I am going to get a t3 from someone unknown ar and unknown condition. When I get it i can get into this......

So Now here are my LOGICAL thoughts (past the frustration)
I know my wastegate is screwing up. Here is why...
I can get to 5psi awsomly but after that it SLOWLY builds up higer even at WOT. My wastegate has been sleved and has a threaded rod so it is adjustable. BUT. When I rotated the houseing it threw it out of wack. So One thought is that it is sticking and thats why it is slowly building boost. I feel a Vac/presure tester will confirm or deny this...

Anyone agree with the above so far.

Additional thought are this.... My distributer cap is screwed (i seen it arching with no wires or grounds near it) So thats adding to the problem. (bad spark causing misses ect) which would make it jump more and faster at high rpm screwing it up more.

Ok now lets go to the next thought. My exaust. Maybe 2 -1/4 is too small for what boost I am trying to get to.

Anythoughts on this????

Final thought.... I am maxing out the turbo at 9psi and 6,000 rpm (turbo is too small)

Any Ideas on that one?

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

Sounds about right except for the exhaust thing. 2 1/4 should not be a problem. It will spool up faster with a bigger exhaust, but it won't cause you to sputter and have eratic boost.

I also doubt you are maxing out the turbo. You should be able to hit a higher boost level. It will just stop building power and pump hot air into your cylinders. :-\

Get a new wastegate and see what happens.
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Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

next time it happens, watch te boost gauge, see if it drops boost during WOT.

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

checked not dropping boost maybe 1 psi. I got another CEL this is the 4th 02 sensor THIS MONTH... Im gonna have to start cleaning them this is getting costly.

Ok I have to move my af/guage and boost gauge and have someone watch it. I SWEAR it feels like a rev limiter. I know its not so i have to get serious on this lol...

Im no doing to much till I get with Pep on a few other things...

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

Are you using an FMU with ghettodyne?? I don't think you are supposed to with the ghettodyne for boost. Maybe someone else can confirm this. Your car might be runnin hella rich under boost. Hope this helps.

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

my car did the same thing, I turned down the fuel at 4500-6500 rpm. It runs way better.

Re:DOHC ZC t25 advise please Dr.Boost, ITS WORSE
 

a/f gauge confirms LEAN long story but i think i am getting it worked out. Lets call it a glitch. Ghettodyne does support boos. it just doesnt do it well for a dohc although that is in the works and getting completed also