blown 944

Funny thing happened tonight.

I took my car out last night and hotrodded the **** out of it. I noticed that even though I didn't get my twin scroll on it that my smaller hotside made a nice difference in spooling the large turbo.

I got to thinking about ..anti lag........what if I changed my hotside to an even smaller unit...home made rev limiter.....blah blah.

came home tonight started researching homemade anti lag rev limiters...then I had an idea about blocking off one side of my twin scroll hotside (T4 .48) that is currently on the car now. Hell it will be cake to do and it may be big enough( I also have a .69 and .82 T4's).

Then I did some googling "blocking divided turbine entry" and came apon this site. If you read though this there are some very good ideas thrown around. One of teh results was a Ford explorer spooling an overly large hotside down from 5000 rpm to 3300 WOW.

there are some good ideas on using a separate WG to allow flow to the blocked side of the housing too. This is my plan .

Tomorrow night I will pull the turbo and make a blocker for one side and re install the turbo and document the spoolup results. Since I have been driving it this last week with this hotside I have very good idea of what pressure is at what RPM (wish I had a logger)

as of right now just for reference I see 5psi @ 3000 rpm and15 psi at 3700 and full boost 25 psi @ 4k.

I will re install my crossover pressure gauge to measure as well.

Here we go again, but this will be far easier than building the twin tube crossover was (still planning on using unless this is good)

TRP951

so esentially you are making the hotside smaller?

spoolin51

Dosent making the hotside smaller cause more back pressure..

TRP951

yep

spoolin51

So basically you sacrafice top end power. Sounds like to me Sid just wants full boost as early as possible.
Sid, have you thought about standalone? That will help spool...

gt37vgt

yeh there is a compact little cast assembly from early 13B turbo's integral gate syle flapper thats shut one scroll get one of them and perhaps even use one of the IHI turbos they are suit they have a good selection of bits and i think garrett compadible

gt37vgt

I also thought of using one of those exhust Y pipe type cutout's valves to bridge twin cross over pips into one for lower rpms

333pg333

How much heat could they stand though?

gt37vgt

what the cast thing or the y piece cut out things ???
I'd say plenty they are made to go right near the collector and they are cheap enough to change out every 18 months .
and once agian let me sing the praises of cooler EGT s for e85

gt37vgt

what the cast thing or the y piece cut out things ???
I'd say plenty they are made to go right near the collector and they are cheap enough to change out every 18 months .
and once agian let me sing the praises of cooler EGT s for e85

blown 944

If I were to "only" block off one side of my hotside yes it would limit top end and create high backpressure , however if you read the thread it goes on to opening up the other side once at a certain pressure.

Therefore you still retain all of the flow of the total turbine area. What it really is, is a variable nozzle turbine housing.

The plan as of now is to:
1) block one side fully just to see the spoolup and backpressure

2) if backpressure is too high (I am betting it will be) then add in a WG to feed the other side of the turbine housing once I hit 15psi controlled by a hobbs switch and a soleniod (like EBC).

3) If backpressure is not too high then I will be able to use an even smaller twin scroll hotside and do the same thing.

The goal is to be able to see 15 psi @ 2200rpm and still be able to run 30+ psi w/o too much backpressure. Looking at what I have done already (running 35 psi) I know that I can flow that much air through the current hotside and the only thing I am doing is restricting the pathway in the lower rpms and boost levels.

Ye I know I could go standalone and anti lag, but who really wants to be using anti lag running around all over town.

Theorizing, it looks pretty sound to me, and the results within that thread show that it can be done even on a small cc motorcycle up to a huge turbine on a ford explorer (that was actually logged)

blown 944

see here http://www.theturboforums.com/smf/in...opic=45148.350

here is the pressure logging page for another modified housing look closely at the TP and boost graphs
http://www.theturboforums.com/smf/in...opic=45148.300

Here is a vavle manufactured to do in essense teh same as teh WG bypass
http://www.spracingonline.com/store/...ool_Valve/3643

porshhhh951

well that looks pretty damn crazy/interesting.

Everything I come to expect from opening up a sid thread.

rlm328

Would be interesting if you could block one side off for the low end spool up but would allow to come on line at about 5500 rpm for the high end.

blown 944

Pretty easy just using an rpm activation switch. However, I like the pressure switch myself b/c there is the possibility (probability more likely)of having too much crossover at 4k rpms at 30 psi.