Whose good with turbos?

I could use some help sizing a turbo. I want to install a turbo on my Triumph TR8. I'm all done with spending crazy money trying to squeeze HP out of those poor flowing cylinder heads. My original plan was to put on a couple of small kkk turbos sourced from VW/Audi 1.8s up front. Since there are no commercially available turbo manifolds for the Rover V8, I have decided to go with a rear mount set up. The engine will be 4.0 liters running with fuel injection. I would like to see a max of 10 PSI boost. STS makes a rear mount turbo for the 4.0 liter V6 Mustang, so that seems like a good place to start. Anybody know which turbo they use. Who can recommend a turbo and why that one? Keep in mind the turbo will be rear mounted, so it presents special challenges not covered by standard turbo graphs.

Oil-cooled T3's are your friend (from nearly everything in the 30's including 83-86 TBird Turbo's, 84-86 Cougar XR7's, Merkur XR4Ti's, etc, etc). No water cooling means less plumbing to run. The .48 A/R exhaust ones ought to be perfect for twins on a 4.0 V8. If they spool too fast you can always move up to the .63 A/R housings. Also, rebuild kits are cheap and they were designed for ~12 PSI at the factory.

I guess I should have said I am going with a single rear mount. It will be much easier to install and fabricate the piping. My plan is to remove the gas tank which is located above the rear axle and put a fuel cell in the spare tire well of the trunk. That will give me tons of room for the turbo and keep the fuel tank away from the heat of the turbo.

P71 wrote: Oil-cooled T3's are your friend (from nearly everything in the 30's including 83-86 TBird Turbo's, 84-86 Cougar XR7's, Merkur XR4Ti's, etc, etc). No water cooling means less plumbing to run. The .48 A/R exhaust ones ought to be perfect for twins on a 4.0 V8. If they spool too fast you can always move up to the .63 A/R housings. Also, rebuild kits are cheap and they were designed for ~12 PSI at the factory.

The T3s you're mentioning are oil/water cooled, I remember this when removing our T3 from our XR4Ti. I do not know about the IHI's cooling setup (they were on the Tbirds/Cougars IIRC).

You need to do some flow calcs, when setting up a remote mount, conventional sizing of the compressor is fine, the issue is in the turbine, you basically want a smaller one for the same sized compressor. There are other ways around this by ceramic coating/wrapping your exhaust to keep the EGTs up pre-turbo, plus a TR8 isn't exactly a long car so the losses could be minimized so you wouldn't need to custom size turbine components. I don't know flow wise what your engine looks like, but Holsets (HY35s/HE351s) may work, just do a flow calc of your engine and overlay it on the compressor maps out there, and they are oil cooled, journal bearing turbos that are tough as nails and cheap to get used, and cheap to rebuild.

I'm pointing all this out because we went from a T3 .63 to a Holset HY35 w/a 9cm^2 exhaust housing on our 2.3L SOHC 4cyl in our XR4Ti and can push 30+psi of boost, if our 2.3L can push that much air for that much boost, I'm sure a bigger engine like the 4.0L would be able to w/o worrying about falloff at the top even only pushing 10psi...

Careful with the rear mount - it gets ugly fast. I don't yet see an acceptable solution to oil the turbo short of a dedicated pump and oil supply. I wouldn't want my engine oil pump forced to do that.

The timing cover has built in ports for running oil lines to and from a front mounted oil cooler. The 4.0 came out of a Land Rover, and good for Land Rover to do this for me. If it can handle pumping oil to a cooler, it ought to be able to get the oil to the turbo. For the return trip I have an inline pump rated for hot oil. I'll use braided lines with AN fittings.

tuna55 wrote: Careful with the rear mount - it gets ugly fast. I don't yet see an acceptable solution to oil the turbo short of a dedicated pump and oil supply. I wouldn't want my engine oil pump forced to do that.

That is the route I'm going to take on the Alfa. Remote mount turbo with self contained pump, reservoir, and cooler for the oil.

how far are you positioning the turbo from the engine? Are you worrying about the lag with not having the turbo close to the exhaust ports and intake ports?

Andrew

I have all the same concerns that everybody else would have about lag and distance. Unfortunately there isn't any place to get turbo manifolds for a Rover V8. I started to make my own, then I came across this rear mount idea. The fabrication involved in doing a rear mount is much easier. There are rear mount kits available for many newer cars. This is mostly do to packaging and the limited amount of space under the hood for a turbo. They seem to work very well, so I'm going with it. Check out STS Turbos. They have some nice kits for Vettes, CTSV, Mustang, Camaro, etc.

If you are willing to do all the needed fabrication for a rear mount turbo why not just make your own log manifolds and mount the things up front where they belong? you may not even have to work that hard either, what do the factory manifilds look like? Maybe you could just make a wrap around pipe to bring both sides together at a Y pipe inside the engine bay and mount a single snail that way.

On the rover engine, can you turn the headers upside-down-and-backwards so they point forwards? LIke this guy:

toohighpsi.com/budgetTT/ He then runs a short pipe from the end of the header to the turbo. You could run a y-pipe to a single turbo. If there's room up front somewhere.

Also, here's an online turbo calculator. Its pretty nifty. You'll probably have to fudge some numbers to deal w/ the remote mount, but you might find it useful:

http://www.squirrelpf.com/turbocalc/

Good luck and post pix of the progress!!

tr8todd said: whose good with turbos?

I dunno, it might be my good with turbos...I am not sure where I left my good with turbos...did you find it?

Can't flip them. Low hood clearance, and generally not a ton of room up front. The engine bay is notorious for the heat coming from the all aluminum engine. The factory installed louvered vents in the hood to help with the heat issue. It just makes sense to stick the turbo out back. Thanks for the link. I played with that before. There are just so many variables that I still have to guess values for. Oh well, an educated guess is better than a shot in the dark.

There has got to be room someplace other then in the back to place those things. What about on each side of the transmission housing? I mean there should be some room there. And as for underhood temps, just get the turbo coated by swaintech and call it a day. Heck you could get the whole block coated if you really think its going to be a problem. Then again heat wrap is a cheaper alternative.

And instead of 2 turbo's you'll be much happier in the long run with a single unit, it will put a whole lot less stress on the engine, and will be more reliable in the long run. The big problem with 2 turbo's is that if something goes wrong with one of the, boost creep or leak, a boost controller spiking, etc. Your going to adversely effect your engine by putting too much or too little pressure on certain cylinders while the other side remains at the same boost levels, causing internal bearing problems mostly. Its alot easier to tune one turbo versus 2 as well.

Andrew