Nearly all of the exhaust pipe has 1/2" thick fiberglass insulation around it, as can be seen in last under the car picture. The car usually is run for a while before a pass while in line so all pipes and turbos are well heated.

 

hmm what about making it a series run setup instead of parallel..compound system i believe it is.. just a thought.. both would spool up relatively around the same time.. or have one turbo spool up a larger turbo..88mm,etc.. so that way you would have more than enough cfm, and at a very quick spool rate..just an idea though..not sure how efficient these systems really are lol..

 

Since these turbos are twin scroll, I just got done cutting out plates to block off one side of the turbine housings. I'm thinking I may be able to get these to work this way since the a/r should now be roughly .5-.6 instead of 1.05. I might even be able to have valves on one scroll of each exhaust housing to take the place of a wastegate since it seems with the housings completely open the setup only goes to 7psi.

The other idea I'm going to try is to use a solenoid to dump fuel into the exhaust pipe when I'm on the trans brake. If that works I'll probably make it work whenever I'm at WOT and under some amount of boost.

I've seen compounds work well, but in that case one turbo is sized for the desired peak power while the smaller one is sized for optimum spooling. A combination of my 91mm and a 60-70mm would work well, but would likely work best with still a smaller a/r and/or turbine wheel than what's on my 70's for best results. I may do something like that some day, but would prefer to not need to use such a complex setup that would require a complete re-piping.

 

i only seen compounds on diesels never on gasengines sumtin to do with the amount of pressure they make or sumtin , im not sure
i allso seen pressure actuated valvebodies that only opens the second port to the turbine of the turbo once it starts making boost to make it spool faster
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I made some block off plates to simulate a valve like that and it didn't seem to make a difference. Surprisingly, the engine can still breathe through only 1 of 4 of the exhaust housing ports. The downside is that it doesn't seem to spool any differently.

When testing the other idea of dumping fuel in the exhaust from my fuel rails, it seems the sudden open valve action causes a starvation of fuel to the motor. I'm thinking this might possibly be from its proximity to the regulator, but we shall see.

 

i am really digging the tpi tb's !!! good lookin set up :clap:

 

did you tried to turn the blockage around so it covered the other hole ? maibe you closing the wrong part of the turbo

 

I have yet to try flipping the plates, and right now they are blocking off the side closer to the compressor. I'm also going to try the fuel solenoid placed right on my belt drive pump outlet to see if that disturbs fuel pressure less.

Thanks for the props! Most people really like the twin TPI's. There's a couple of kinda high dollar shops in the area, and people have asked if this or that was done by them...NOPE, all me!

 

a while back there was a guy here on the forum that was using a wastegate to open and close the second port on the turbo
he made a Y in the exaustpipe and hooked one up direct on the one hole of the turbine and one with the wastegate in series on the other hole , havent heared from it in a while , not sure if it would work either

 

The plates blocking off 2 of the 4 turbine entrances did help. Last time I ran both turbos they couldn't spool up even by the top-end. I would end up all in 1st gear, 4psi in 2nd, and 7psi in 3rd. With the blocking plates in there I'm slightly better in 1'st gear, and 2nd gear is like instant boost to the requested 15psi I had on the tune. Not sure exactly what would result from boost in 1st gear, but at 15psi through 2nd and 3rd with no water in the intercooler and intake air temps around 115 the car pulled [email protected] e.t. That's with high 1.9x 60' times that I know can be 1.30's with just 6-8psi and bigger tires.

Probably not this season, but I'm thinking of getting rid of the wastegate...kinda. Since with the gate shut and the exhaust housings completely open brings at max 7psi, that sounds fine to me. The quick spool valves will act as the wastegate by altering the pressure of the air going through the turbines instead of the mass or volume of flow like a normal wastegate does. This method should provide for lower exhaust pressures than a normal wastegate, which leads to more air through the engine and more power.

 

uhm i would never do that ever its like taking the safety off a steamboiler , wat you could do is just adding a lot of spring to keep it shut untill 20 psi or so ........ hmmm just remember watching mythbosters a while back the used thin metal burstdisks bolted to a big pipe to measure peakpressure in the outside air or under water , nothing to do with the car or turbo offcourse but you could use one refferenced at say 20 psi as a "ïf all else fails"safety over the hole left by removing the wastegate or next to a wastegate for that matter . you can make the pipe pretty big so the turbo whont get any pressure when it gets above a certain treshold

 

I should still redesign my wastegate/y-pipe setup to where it doesn't push the wastegate open so soon and I do have enough spring that should hold very tight to provide as a "burst plate" in case it tries to boost to the moon.

 

glad to see the blockoff plates are working for you, did u flip them around so u blocked off the rearport instead of the side closest to the compressor housing?

 

I haven't flipped them yet.

 

Neat build. I was wondering what and where you got the insulation you used for the exhaust? Looks like a foil backed insulation? What do you think of it?

 

I got the insulation from st.john316 on ebay: http://motors.shop.ebay.com/st.john316/m.html?_trksid=p4340.l2562
The 1/2" thick stuff is what I'm using. I thought it would work better than it does, but it definitely helps. The biggest thing I don't like is that it seems to smoke often and I've had a couple people think my car is on fire.

 

flip them around u will see a ,much bigger difference

 

gas compound



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to op sweet build

 

Thanks! Don't know when I'll have time again to screw around with this, but have decided that there is no making these rear mounts work without doing something I'd rather not do like nitrous, compounds, or converter change. I still have the forward facing headers I made a couple years ago and should be fairly easy to put the turbos in the engine bay and see if that can make it work. If it still isn't enough, a swap to some turbos with smaller turbines should work and be almost a bolt on.