Problems I had last season were slow spooling and not enough traction. I know from past setups that a wider set of tires could solve the traction, but I'm looking for more weight in the rear to do the same while keeping the smaller tires. Last time I had the car on the scales it was something like 1900lbs on the front and 1700lbs in the rear. By rear mounting the turbo stuff I'm thinking I should be able to get it to possibly have more weight on the rear than the front.

So far I have the main 3" exhaust pipe fitted for most of the length. In this first picture you can see the oval section of pipe laying on the floor that will be positioned under my driveshaft to move the intake air from the intercooler to the engine. Looks like I'll be able to keep everything higher than my trans. crossmember and keep ground clearance to a minimum of around 4-4.5"
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What can be seen of the turbos at bumper height
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Top view of how they are mounted
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I'm also using twin TPI throttle bodies, and I'm quite happy with the intake adapter I spent much of today making for them
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The intake tubes going to the throttle bodies will come through the fenders and combine into that one oval pipe seen in the first picture, and that should be the next thing I get to working on.

 

nice setup love to see more of it , i was wondering if you couldnt put the chargepipes through or against the back of the rockerpanels under the front fenders up and intoo the enginebay
or if its a true racecar have the ice chest intercooler in place of the rearseat or even further back in the trunk and lay the chargepipe through the interior

 

The w/a intercooler and water tank will be mounted just above the turbos, with insulation obviously. I had the intercooler in the passenger foot area last season and I didn't like it, so keeping tubes out of the interior is a goal too. I almost did run dual pipes for the intake charge under the rockers, but decided it'd be too hard to get the pipes out there and/or take many bends to do it.

 

Revised the turbo placement after long study of how in the world I was going to run the pipes. Now there will be short straight pieces right into the intercooler (the intercooler requiring some modification of course), and one 3" pipe that ties into the driver side one above the axle.
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This placement shows them much more than before, which I'm not too excited about, but piping is much easier.
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This is the beginnings of the y-pipe/wg:
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How big is your engine? I ask because unless you have A LOT of cubes, you may want to think about making the piping back to the turbos smaller than 3". The smaller the pipe, the more velocity and heat the exhaust gases are going to have, thus being able to spool the turbos faster. With the turbos being as far away from the engine as they are, that is just going to allow the exhaust more time to lose heat and slow down.

 

Engine is a 406 and all pipes are designed to flow around 300-350ft/s which seems to be a fairly agreed upon number. Much smaller than the single 3" pipe will begin to become more restrictive than the exhaust housings of the turbos, so I'm not sure how that'd work.

 

Are you running a 3" pipe to each turbo or a single and then splitting it near the back? I'm not clear on that one and it's hard to tell from the pictures.

 

Out of the two 3" pipes seen above the axle, the driver side one will be the intake air going to the motor and the passenger side pipe will be the exhaust supplying the turbos. So, yes that one 3" pipe will split to 2.25" pipe to supply both turbines.

 

Oh ok, that makes more sense now. I thought you were running two 3" pipes from the engine to each turbo.

 

Can't wait to see how this turns out! I asked a question about splitting a 3" exhaust to feed two rear mounts a lil while ago so I'll be very interested to see the results.

 

More info on the twin TPI throttle bodies.

How are you going to control them, what I mean is how will they open? DId you flip the brakets for the actual part where the throttle cable goes on on one tb?

Im loving it so far.

 

there nice kits on the market for the weber type carbs they have a rotator in the middle holding the cable and two bars one going to each of the carbs , you could use sumtin for a motorcycle too i seen kits for dual carbs for a harley that had a nice little gascablesplitter in it

 

The last picture where the throttle bodies can be seen shows the linkage I made. The throttle cable will pull on the passenger side TB at a point just above the purple fuel rail. The cable can move about 5/16" to open that TB before the linkage grabs the driver side TB to start opening it too. A ratio is involved there too in order to have both TB's end up at WOT at the same time like they do.

 

Sick setup man looks like a logistical nightmare with all the pipes and oil feed/ return pump tank etc. Good luck can't wait to see it run! Et/HP goals?

 

I'll be happy if they can end up spooling decently so that my 146mph on 15psi goes with the 8.9 - 9.0e.t. that it should. The car is only certified to 8.50e.t. and I'll likely get yelled at long before that for not having a chute on the car after 150mph, although there should be more than enough power to go much faster than either of those.

 

Only have worked on the car probably a week or two worth of days since I last posted, but I did start the car up and drive it to work a few times...once where it had an oopsie with a trans line coming undone that left a good couple hundred foot long stain on the road. Don't have the turbos hooked up yet, but they are placed more like they originally were except both rotated 180 degrees. I'm not sure yet how I want to do the oil supply for the turbos, and the final piping with the intercooler will probably take a while as well as some reworking of the pipes welded onto the intercooler. Anyway, here's pictures of stuff that is basically done except for maybe some prettying up:

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I'm thinking I'll probably end up hooking up one of the turbos initially just so I can at least run like 6psi cause without boost this 12 second car feel SLOW! This should also give me an idea of how one will spool up so I can compare that to the twins spooling together. I do really like how the throttle body setup has the car drive like stock until 20% throttle where the driver side throttle body begins to open up.

 

any updates on this car ?

 

Running one can go to about 3.5psi and spools pretty well. It ran an 11.5, but could do 11.2 or less if there was more traction. Then I tested out running both of the turbos and I get no boost until the end of first gear. I've been trying to get the best of both spool and boost. I'll probably end up using some valving to run with only one turbo until a couple psi to then bring in the other one and maybe moving the cam to 108ICL instead of the 116ICL I'm at now.

 

I've been trying out stuff and found out a couple things. The wastegate is getting pushed open prematurely. The spring labeled for 5.4psi holds about 4psi withOUT a manifold reference while running a single or both turbos. Swapping in the 9.77psi spring and adding closing pressure to the gate from the manifold with a single turbo brings 10psi and seems that's all it can do. That same setup running both turbos never reaches full spool even at the end of a pass... 1'st gear no boost, 2nd 4psi, 3rd 7psi. Still not using the a/w intercooler, no water in it anyway, but the single turbo runs better since it spools faster and gets more boost to get me 129mph and 11.4's with still slow spooling and 1.9x 60' times. These turbos seem to be pretty good for the price in a single setup, but the exhaust side is just way too big for any twin setup. I bet if these were made with a smaller turbine wheel and a .68 or so a/r like I've seen on many other t4 turbos, they would work much better. I'm going to see if I can test a spooling technique with what I have, but will likely end up putting the 91mm back on in some shape or form.

 

you could try isolatng the exaustpipe to keep the heat in and/or maibe warm it up before a run , see if that works