New Acquisition: dohc turbo

p8ntman442 · Post by **p8ntman442** » Mon Sep 15, 2008 12:37 pm

fieromadman wrote:God I hate prooving people on the internet wrong...

Here's pictures to show you why your wrong:

Start off with a basic Diagram. This shows that none of the Vac lines are for "IAC feed."

#7 feeds the IAC I think.

Aaron · Post by **Aaron** » Mon Sep 15, 2008 12:39 pm

No number 7 is for the breather line, and it is solely for that. That goes to the only casted port before the throttle plate, and this casted port only feeds that line, it isn't connected to the IAC passages.

This is a very unconventional way of doing the idle passages, when most every other car has casted ports inside of the TB, but it's the way it is.

Series8217 · Post by **Series8217** » Mon Sep 15, 2008 2:45 pm

I have that TB sitting on my desk.

I have confirmed that Aaron is wrong, and fieromadman is correct.

The idle passage is the same as it is on every other modern GM TB I've seen. There is a port before the throttle blade and a port after the throttle blade. The IAC bridges the two ports. You can look through the port on the back and SEE the IAC pintle. For the other direction, you can remove the IAC pintle and look through the port to see the other side of the TB. It's pretty obvious! The IAC pintle hole is machined through to the cast passage.

Hey look, I can run a wire through the FRONT of the TB, through the slightly opened IAC pintle, and out the back passage to behind the throttle blade. I guess Aaron thinks that air has to follow special paths designated by him. I say it can follow my wire.

fieromadman · Post by **fieromadman** » Mon Sep 15, 2008 6:25 pm

Series8217 wrote:I have that TB sitting on my desk.

I have confirmed that Aaron is wrong, and fieromadman is correct.

The idle passage is the same as it is on every other modern GM TB I've seen. There is a port before the throttle blade and a port after the throttle blade. The IAC bridges the two ports. You can look through the port on the back and SEE the IAC pintle. For the other direction, you can remove the IAC pintle and look through the port to see the other side of the TB. It's pretty obvious! The IAC pintle hole is machined through to the cast passage.

Hey look, I can run a wire through the FRONT of the TB, through the slightly opened IAC pintle, and out the back passage to behind the throttle blade. I guess Aaron thinks that air has to follow special paths designated by him. I say it can follow my wire.

[/img]

Thank you... I was seriously about to go postal.

Shaun41178(2) · Post by **Shaun41178(2)** » Mon Sep 15, 2008 6:28 pm

thanks guys. it seems they all go to a valve cover or breather setup of some sort. I will just plug them off.

MstangsBware · Post by **MstangsBware** » Mon Sep 15, 2008 7:21 pm

Aaron wrote:No number 7 is for the breather line, and it is solely for that. That goes to the only casted port before the throttle plate, and this casted port only feeds that line, it isn't connected to the IAC passages.

This is a very unconventional way of doing the idle passages, when most every other car has casted ports inside of the TB, but it's the way it is.

Are you sure you are ready to take someones money to do a swap in a car that they want to be dependable? I am losing my trust in your swapping abilities.

Shaun41178(2) · Post by **Shaun41178(2)** » Mon Sep 15, 2008 7:36 pm

I took the upper intake off and discovered the line for the map sensor was pinched closed. Not sure if this was the whole cause of it not running right, but its possible I suppose. Will find out once I get it all back togethor.

I need a vacuum source still so I guess one of hte tubes off the tb will be the source for that since there are no provisions in the intake itself. Kohbyy seemed to have that figured out as I did get good vacuum from where it was being referenced from.

The vacuum block on the setup now will probably be replaced with a nice golden eagle one. Just not enough open spaces on this one as I don't want to "T" everything. I want everything to have its own vacuum source.

Aaron · Post by **Aaron** » Mon Sep 15, 2008 9:24 pm

Shaun41178(2) wrote:I took the upper intake off and discovered the line for the map sensor was pinched closed. Not sure if this was the whole cause of it not running right, but its possible I suppose. Will find out once I get it all back togethor.

I need a vacuum source still so I guess one of hte tubes off the tb will be the source for that since there are no provisions in the intake itself. Kohbyy seemed to have that figured out as I did get good vacuum from where it was being referenced from.

The vacuum block on the setup now will probably be replaced with a nice golden eagle one. Just not enough open spaces on this one as I don't want to "T" everything. I want everything to have its own vacuum source.

MstangsBeware, lose all the confidence you want. My car has a better swap than your's. And his car is getting a swap that has been proven to be nothing short of perfect.

I guess I'm wrong. I'm going to go look at my TB again, I don't know why the tests didn't pan out. Maybe the passage is clogged in it (JY intake setup that sat through a few CO winters with no hood).

That will affect your car's running ability, for sure. If nothing else, it will delay ECU response to airflow changes.

I T-ed nearly every vacuum line on my car, no problems at all. I have a main vacuum line, a 5/8" line, go to the brake booster. From this, I have 2 Ts. Off each T is another T. Off one of these T's I have yet another T. I have to feed the FPR, PCV, WG, BOV, PCM, boost gauge, and the brake booster. Those vacuum blocks are really nice, but damn they are expensive. I just went to Home Depot and built my own with brass fittings. It may not look as good, but I wasn't about to spend $100 on my vacuum lines, without gaining any function.

MstangsBware · Post by **MstangsBware** » Tue Sep 16, 2008 1:54 am

Aaron wrote:
Shaun41178(2) wrote:
MstangsBeware, lose all the confidence you want. My car has a better swap than your's. And his car is getting a swap that has been proven to be nothing short of perfect.

Talk to me after 35K and some track time.

p8ntman442 · Post by **p8ntman442** » Tue Sep 16, 2008 6:41 am

I have to apologize, I was wrong as well, the quad 4 also uses a passage from in front of the throttle plate on the inside of the TB. I tried it on our race car last night. THe large vac port just caused a hugh leak and high idle.

Kohburn · Post by **Kohburn** » Tue Sep 16, 2008 7:32 am

Shaun41178(2) wrote:I took the upper intake off and discovered the line for the map sensor was pinched closed.

damn would suck for me if that was the source of my tuning problems, good catch.

The vacuum block on the setup now will probably be replaced with a nice golden eagle one. Just not enough open spaces on this one as I don't want to "T" everything. I want everything to have its own vacuum source.

those look nice - the one on there I made from round stock.

The Dark Side of Will · Tue Sep 16, 2008 8:07 am

Aaron wrote:I guess I'm wrong. I'm going to go look at my TB again, I don't know why the tests didn't pan out. Maybe the passage is clogged in it (JY intake setup that sat through a few CO winters with no hood).

Chill out, dude. Notice that Steven's IAC pintle is open. If the one on your TB were closed, what would the airflow path be?

Aaron · Post by **Aaron** » Tue Sep 16, 2008 11:46 am

MstangsBware wrote: Talk to me after 35K and some track time.

Working on it. I got 6k with track time on the first DOHC swap, all problem-free.

The Dark Side of Will wrote: Chill out, dude. Notice that Steven's IAC pintle is open. If the one on your TB were closed, what would the airflow path be?

I thought of this, that's why I pulled the IAC out altogether.

Shaun41178(2) · Post by **Shaun41178(2)** » Wed Sep 24, 2008 7:40 pm

New pics. Just doing some trial fitting to see what I have to work with. With the vband flange I will be able to run at least a 2.5 inch mandrel bend out of the turbo now. Its got a lower profile then the old turbo with the internal gate. This internal gate only really gave enough room to use a 2 inch bend out of the turbo.

The hotside has been heatcoated to 2k degree vht paint and so has the trunkside exh manifold. Which you can see in the pics. I did that since it had a bunch of scaley rust all over it. So I took a wire wheel to it to clean it off then painted it and cooked it.

So 2.5 inch is doable, if I want to go 3 inch out of the turbo I will have to put a small notch in the trunk. Cool thing is though it will still be hidden behind the carpet. If I go 2.5 inch I will probably just go 2.5 inch the whole way and forego the 3 inch setup. With how short this is going to be of an exhaust, 2.5 inch should flow more then enough. I think it can flow 400 hp or so right?

Anyways here are some pics. Full size as I didn't feel like scaling them down.

http://www.shaun.saturnet.net/pics/dohc/100_1534.JPG

http://www.shaun.saturnet.net/pics/dohc/100_1535.JPG

http://www.shaun.saturnet.net/pics/dohc/100_1536.JPG

http://www.shaun.saturnet.net/pics/dohc/100_1537.JPG

http://www.shaun.saturnet.net/pics/dohc/100_1538.JPG

http://www.shaun.saturnet.net/pics/dohc/100_1539.JPG

http://www.shaun.saturnet.net/pics/dohc/100_1540.JPG

http://www.shaun.saturnet.net/pics/dohc/100_1541.JPG

Aaron · Post by **Aaron** » Wed Sep 24, 2008 8:16 pm

All of the factory manifolds do that rust thing, but it doesn't hurt them at all. Being like 1/2" thick cast iron all of the way around, they are indestructible. But I painted the ones on my maroon car so they look pretty (Even though you can't see them).

I'm curious as to how long that VHT paint lasts. I was going to do something like that on my exhaust so it wouldn't rust, but the last "High temperature ceramic flake exhaust coating" spray paint I used sucked, and it was on a stock motor. It's already all chipped off and the pipes starting to rust. So I had the entire exhaust on my black car ceramic coated (Chi Ching).

Go 3". You won't regret it. Although 2.5" can support 400hp, it won't be the most efficient way. The best way to gain power in an engine is through the exhaust. You get better MPG, you can make more power with less boost, your IATs drop, you can run more timing or lower octane, less stress on the engine block, and your underhood temperatures are lower. So while 2.5" can support 400hp, a 3" would be much better in so many ways, and completely worth every dime it costs. Go 3". Plus, there is no downside to the larger exhaust, besides price and weight. The bigger the exhaust, the better on a turbo motor. You can't go too big. I wish I could fit a 3.5, even 4".

I'm sure glad I don't live on the east coast. Shit rusts fast, and hard.

Series8217 · Post by **Series8217** » Wed Oct 01, 2008 12:51 am

Bump!

You driving this thing yet?

Shaun41178(2) · Post by **Shaun41178(2)** » Wed Oct 01, 2008 11:21 am

no not yet. I am waiting on the wastegate, exhaust piping, intercooler piping which all still hasn't arrived yet. Its probably going to be another month or two before its driving.

Shaun41178(2) · Post by **Shaun41178(2)** » Wed Oct 29, 2008 9:23 pm

I have the wastegate and exhaust all done. Just need to work on the intercooler piping.

http://www.shaun.saturnet.net/pics/dohc/100_1542.JPG

http://www.shaun.saturnet.net/pics/dohc/100_1544.JPG

whipped · Post by **whipped** » Wed Oct 29, 2008 10:14 pm

silicone on your exhaust?

Shaun41178(2) · Post by **Shaun41178(2)** » Wed Oct 29, 2008 10:24 pm

yea copper exh silicone I guess. I have a metal cometic gasket in there too but I wanted to make sure it all sealed up nicely. It got dark before I could take anymore pics but I might have a couple more tomorrow.