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A friend of mine just bought an 1987 IROC for a single turbo project and I am helping him with it. He bought the car on the 6th of January and we have already removed a lot of parts.
Parts removed:
The idea is to modify two stock C4 Corvette headers and put a single turbo over the battery tray. ( Like Guido did )
Both headers will be modified similar to this Callaway TT header but without the bend before the turbo flange.
The driver side header will be mounted upside down to clear the power steering pump.
The passenger side will be mounted the right way so the forward pipe will be just above the engine mount. A Y-pipe will then be used from the headers to the turbo.
This is a corvette header mounted upside down on the passenger side.
If you move the engine backwards like 3 feet you can probably get away without shortening that Volvo truck intercooler. :-)
Looks quite similar to my Saab Scania truck IC. Well, mine has been cut in half and it´s still too big to fit. I need to shorten it and I´ve got a CNC milled endplate that can be pressed on the tubes and then welded. We´ll see in a few months what mine will look like. Execellent choice though, cheap and BIG!
I´ll ty to squeeze my IC down and in the place where the AC heat exchanger were initially.
Measure the compressor inducer and the turbine exducer. On the small one they will be 63/72mm and on the large one they will be 67/77mm.
The turbine housing size will be cast into the housing in a few places, usually the one that you can rely on is the one cast inside the inlet to the turbine. It's usually covered/filled with carbon but if you run a sanding roll around the inside you'll remove all the carbon besides what is in the numbers...
We are not building an all out racer, just a fun street car. We are leaving the engine stock for now. Keeping the boost down at a safe level we might get 300-350 rwhp and enough tourqe destroy the th700r4 ...
We are not building an all out racer, just a fun street car. We are leaving the engine stock for now. Keeping the boost down at a safe level we might get 300-350 rwhp and enough tourqe destroy the th700r4 ...
The "small one" should be good for about to 1000hp (at the crank). At 300-350hp you'll be butting up against the surge line fairly often. Unless you got _really lucky_ you've probably get a 22cm^2 turbine housing also which I would be surprised if it would spool well on something that mild (there are 18 and 19cm^2 housings available but as far as I know they are rare everywhere but Australia and the middle east)
I've got a small HX50 and a small HX55 here (which happens to be identical dimension wise to the large HX55 with a different housing camping arrangement) as well as an HX40/H1E (it started as an H1E which is almost identical to the 40 and while rebuilding it I used the HX40 parts that were different from the H1E, so it might as well be an HX40 now). One of my current projects is a single setup that will work with any of them and I'll probably just use the H1E till that proves to be too small (it should top out somewhere just short of 800hp, so that's not that likely any time soon, at least not on a stock, L98 long block)
The Corvette headers might be on the small side, but they saved us a lot of work. The drivers side was easy, only one weld per exhaust port. On the passenger side the it was a bit more work to make room for the downpipe and the pipe up to the turbo.
Your header is more work, but it should support more power too.
Originally posted by 85ttcamaro A friend of mine gave me the manifolds, they came from a mid seventies 1/2 ton truck, small block 350.
while browsing pics on your cardomain page i noticed that bonnet your using clears the stock hood. i wanted to know what intake manifold your using, how tall that bonnet is, and if youve and any driveability issues with it since im guessing its pretty short to clear the stock hood.
The manifold is a weind Stelth. The bonnett is only about 3" tall, my goal was to clear the hood. The driveabilty is good, i drove it to work every day last year including the hot days and on the wet days.
This was my first attempt at a turbo on this car and i think in the future i would us a Megasquirt fuel system. The carb can be a bit of a pain some times.
so wait a sec....youe still got the choke horn on the carb and dont have any driveablilty problem due to air turbulence or any fuel dist. problems w/ the dual plane intake? how much boost are you running?
I removed the choke horn and smoothed everything as much as possible. Sorry i don't have any pictures of the carb without the bonnet on.
I usually run about 9psi of boost, i do have some detonation, i have run12psi but there is a lot of detonation. An intercooler will help as well as boost retard neither of which are installed. I haave other projects going on at the same time so i have to do what i can.
Looks like nice parts. I made the big holes in the flanges myself, a very time consuming job. The exhaust ports in the head flanges (chaindrilling, had to make like 60 drill holes using a 1/4" drill) for each flange, and then smooth it out. Then you have the two flanges on the turbo, even more holes.
Thank *** I had quality brand drills (Osborne), I tried some other brands first (Clas Ohlson, Jula, Biltema) and they didn´t last long.
It is not my welding skills you see there. At least the pipes are leak free and the inside looks a lot better. You can cover a lot in heat bandage so it is not a big deal.
Both pipes are to the wastegate. It is a dual inlet turbo and we have separate pipes from each cylinder bank to the turbo flange. Then one small pipe from each to the wastegate.
I'm not so much worried about the welding skills as I am about the method. Those headers are 409 stainless and flux core is probably closest to 1018 (or lower grade) mild steel. It will probably hold with just a bead around each joint but I suspect that it will eventually crack with anything more then that (the expansion rate of stainless is much higher).
Interesting about the split turbine housing/wastegate, but I'm betting that it's unnecessary. What difference does it make if you vent it from both or just one? You're still bypassing the same amount of exhaust gasses. FWIW, the W housings (like the HX50W) with built in wastgates only connect the wastgate flapper to the back half of the turbine housing. I'd be much more worried about getting the best flow through the wastegate to make it as effective as possible then about even flow.
For that matter, I'd probably connect the 2 sides together somewhere anyway to even out pressure on both sides if there ends up being any difference.
There will be a "Y" where the two pipes end to a single 2" pipe to the WG. Both exhaust ports merge at the turbine wheel so that will balance the exhaust pressure. Conecting only one pipe the WG would probably work too but I think the flow will be more balanced with one pipe from each.
This is another turbo exhaust header with one WG pipe from each.
You´ve done the right thing to connect them both. And even though I know that your ambition is set to just produce more power by using a turbo and for as little money as possible - I would have choosen another positions for the WG. A position with a more straight path from the "collector".
You better spend some time thinking about how to get as much exhaust to the WG as easy as possible. Seeing an Alfa Romeo loosen it´s intake due to the lack of a good engineered wastegate system makes me a little bit anxious.
Or just build it and try it - the worst that can happen can be a very cool experience.
Rule of thumb! "The exhausts should enter the WG as easy as the turbine inlet".
Nice to see you´re working so fast - I´m impressed.
The longer WG pipe from the passenger side exhaust actually has a good location. It is a bit difficult to see in the picture but it has a nice angle fron the outside of the bend. It is also almost straight across from the #2 exhaust pipe.
The pipe one the flange (driver side) is not as good. It is almost straight out fron the side of the pipe. We used a bend there too to get a better angle to the exhaust flow. If it not good enough then we can weld a short extension into the pipe to get better flow to the WG. It is possible to do that thru the hole in the turbo flange. That will restrict the exhaust flow some so I rather not do it.
We decided to try another intercooler from a VOLVO truck before cutting the SCANIA intercooler. The VOLVO was about the same width but is not as tall. The good thing with this VOLVO intercooler is that the core has lager air tubes with internal fins for a more efficient heat transfer.
Sorry, not really on topic, but did anyone besides me notice the ground strap from hell going from the driver's side head to somewhere on the driver's side strut tower?
no I didnt, I cant find it now. But I do know we used to put them on cars at the tranny shop because poor grounding on the stock strap can cause a huge variety of odd problems.
I have seen bad ground straps cause the following ailments with ruined:
torque converters
tranny pump and or bushings
starter ring gears
rear main bearings
shifter cables (manual FWD or fwd/rwd automatics)
pilot bearings
stator bushings (inside a tranny)
center support bushings (inside turbo 400's)
even saw a mustang that had a smoking e-brake cable every time it was started...
Electricity is lazier than a politician, it always takes the path of least resistance.
That is a temporary ground strap because it is way too long.
You see it from the cylinder head to the left strut tower:
We spent a lot of tome to clean up the wires. We had everything apart and a lot of wires removed from the harness. ( Cruise control, AC related, Emissions ). We did not cut any wires, we only removed them from the harness and taped then together. A lot of them are hidden under the power brake and the rest are in the right fender. We also rerouted the wires to get them away from the hot headers and Turbo.
Stock you have one big wire from the battery to the starter. A lot of fusable links that power the rest of the car is bolted to the same starter bolt. We ran an new power cable from the starter thru the firewall and to the new battery location in the trunk.
The stock ground goes from the battery to the engine block. We grounded the battery in the trunk and that is why we need a good ground between the chassis and engine for the starter current.
cool. but either way a good ground between the battery and the block and the chassis and the block (as close to one of the starter bolts as possible) is a good idea.
Wow, that IC almost look like a stock item on these cars. Not that much work to get it to fit. A really good choice.
Nice work JoBy, will be cool to see this car on the roads soon. Damn, yesterday the snow was gone after 5 days of hot weather, but tonight we got some more.
Originally posted by JoBy We decided to try another intercooler from a VOLVO truck before cutting the SCANIA intercooler. The VOLVO was about the same width but is not as tall. The good thing with this VOLVO intercooler is that the core has lager air tubes with internal fins for a more efficient heat transfer.
we have some of those trucks here too Joby. Can you tell us more about the truck it came from? (B4Ctom1 warms up his cutoff wheel)
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