grantmac

I'm seriously thinking about going turbo and want to start collecting my bits and pieces. I figure I'm only young once and should go for it, that and I have a line on a daily driver/winter beater. Anyway, I was wondering if I could use a regular garret T3 for a low boost ~6psi setup. I want to be able to spool quickly for good mid-range. Probably going to run without and intercooler because I don't really want to boost more than that. My only concerns are ability to run pump-gas (be really nice if I could run 87) and plumbing all the lines. I'd build the exhaust manifold so that is no problems. Any of the experts have any suggestions. Carb would probably be a blow-through webber 48IDF.
Thanks,
Grant

coldy13

Running pump gas won't be a problem. I run up to 17psi with the normal high comp 12a rotors on 92-94 octane. I'm not sure about the IDF carb though. I'd go with a DCOE.

grantmac

So I'm guessing I'd be fine with 87 octane on only 6psi, and 92 isn't that muchmore money. What turbo are you running? And are you intercooled now? The IDFs are really popular for VW blowthrough applications and are pretty cheap so that s what I'm going with. I'm also going to lock my timing by taking out the springs in the advance, or welding. Also do you think I'll need a rising rate FPR with this low boost?
Grant

P.S. Just for laughs whats your fuel milage like?

coldy13

I'm intercooled now, but before this I ran a non intercooled setup with a nikki carb at 16psi. You always need a FPR running boost. If you've got the normal 4-5psi of fuel, and 6psi of boost, fuel won't be able to even get into the carb.

My milage isn't too bad. I drive it hard almost all the time and I get 16mpg highway and 12mpg city.

85rotarypower

I don't think you should run 87 octane even in low boost apllications, and especially not anything lower than 92 without an intercooler. I'm not sure, but I think the 2nd gen TII cars run 7psi boost stock with low comp rotors and an intercooler and they still recomend you run high octane pump gas.

steve84GS TII

Detonation is the bane of turbo rotaries.Run premium,its a small price to pay for a powerful sports car.

The T3 is gonna be really responsive,but its gonna run out of steam.When the turbo reaches its upper effeciency range limits,it begins to heat the air more.Not running an intercooler will exacerbate the situation and could lead to probelms.
Rotaries move a lot of air and need pretty big turbos compared to even mid sized piston engines.The TII turbo(Hitachi T18) is bigger than any factory turbo Ive seen on a car.Many 2.0L piston engines have very small turbos by comparison(Eclipse,MR2,Starion,MkIII Supra).The T18 is more like a T4 with a smaller compressor.The bigger hot side allows higher exhaust flow,the smaller compressor provides responsiveness and quick spool.Plus the 89-91 turbos have great wastegates,are easily found and have a good exhaust manifold design that can be adapted to a 12A or 13B easily.If it can make 8psi on a stock 13BT,then 6-7psi on a 12A would be a piece of cake,which is good if you dont run an IC.

grantmac

Well I've got a 5.75psi carter and holley 0-4psi FPR right now, but I suppose it would have to be a rising-rate to work. As far as running 87 octane, I've heard some of the guys running stock T2's use it regularly so I guess it all depends. 16mpg ain't all that bad, I don't have a huge lead foot so it probably would be a bit better. I certainly don't really drive the highway for more than an hour at a time more that once a week.
Grant