Skunk Workz

Given the stock cam timing and the stock turbo efficiency in regards to back pressure,no wonder... the cam's a necessity though.

hosrom_951

Note: Stock turbocharger is good enough to 17psi if you are lucky (the weather is nice), 18psi would be pushing it.

At 19psi, the temp out of the intercooler was over 21 degrees hotter than that of 18psi......talk about efficiency.

Campeck

thanks serge. ill try and play around with a to4e's compressor map. jeez. here comes all the math again.

Geo. im not going to shoot for 12 first. i know somethign bad woul dhappen if i did that. 8 psi is perfectly reasonable. then after a while push it up psi by psi. again...if the engine breaks, its not the end of the world.

Fishey

Race fuels

Or make your own..
Formula #1 - Toluene
R+M/2.........114
Cost...........$2.50/gal
Mixtures with 92 Octane Premium
10%...........94.2 Octane
20%...........96.4 Octane
30%...........98.6 Octane


Formula #2 - Xylene
R+M/2.........117
Cost...........$2.75/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........97.0 Octane

Regardless of your poison I suggest mix in 4oz of marvel mystery oil with every 1 gallon of additive used. Since both are dangerous to fuellines without MMO.

http://www.rbracing-rsr.com/turbo/Tu...s/td04-15g.gif

15g Turbo would do the job nicely and they are cheap!

BeerBurner

I don't have much to add to this other than to wish Campeck good luck! <---- root beer 'cause you're too young

BB.

nine-44

You gotta have a plan, and make it close to what you want to do. I wouldn't suggest to build it for 5 psi and maybe work up to 15psi. It will be two totally different setups if you do it right. There's alot of good info here, just listen to it. The head design is lacking, especially for the compression and expected boost. When I was planning out my NA turbo setup, there was no way I would have done it without knock control. By the time I had it all planned to make it into a turbo, it was basicly an over priced 951 motor with NA pistons. I'm not saying don't do it, I'm saying don't do it unless you are going to do it right. I wish I had the money to go 16V, it's probably the best chamber and head design that would bolt onto a 2.5. I may just say screw it and do it anyway, dunno, it'll put me back an extra year. That may be what it takes to do it right istead of being let down first. We'll see. Good luck, I really want you to prove me wrong, I really do. For the budget and the parts being used, shoot for maybe 10 tops, plan for 7-8. BTW, a T-3 Garret from a Turbo Coupe would probably be decent on there. Check out www.turboford.org and see which cars had the bigger AR, I think it was the earlier ones without intercooling.

kennycoulter

ealry t-coupes up to 86, and early merkurs up to 86. svo's from 84-86 had the bigger t3 instead of the small ihi. svo's had different a/r ratios on 85.5-86. i think .63. .48 on early? maybe backwards from that. check out www.nato.com or even www.svoca.com>>>>just dont ask them questions. theyre all elitist dicks on there, and wont give you info unless youre restoring an svo.

Geo

As several folks have said, modern turbos significant improvements over any 80s turbo. Get the best you can afford. A Garrett GT turbo would rock but they cost as much as most NA 944s are worth!

944CS

less than 5 psi and once you are moving, yes it does make negative temp...why is it hard to believe that the intercooler is doing its job?

944CS

my point was that the "log" manifold is going to hurt spool time because exhaust gases are going to be fighting to get out of the combustion chamber instead of flowing more freely with a 951 manifold to the turbine wheel

Skunk Workz

Nope... unless Campeck makes each runner do a 120-degree turn before it enters the main part of the exhaust,or makes the "log" so small it's silly (that is,makes the log in (much) smaller tubing than the outlets) I doubt he'll see many problems. The SAAB 900 Turbo 2-litre 8V uses a similar layout to what Campeck makes,a 4-1 cast iron log manifold made with sensible runner diameters,and the length between the exhaust ports and the turbo is about the same. It happens to have full boost (11 psi or so) at barely 2200 or so rpm...the car is actually renowned for it's quick spool. Two factors on the SAAB does this. The turbo itself,which is a T03 without enourmous backpressure,and the stock cam,which has a rather unusual timing.

Geo

Uh, my understanding of physics my be wrong, but I don't see how it is possible to create a lower temp than ambient. Assuming 100% efficiency the best you could hope for is ambient.

Please explain how this works.

inactiveuser92616

the only way you could use an air to air intercooler (without misters and other cooling aids) to get below ambient would be to have the air expand after the intercooler... effectively turning your air intake into a refrigeration cycle.

Geo

Misting units wouldn't lower the temp below ambient unless the fluid used to exchange the heat was cooled below ambient.

Expanding the air at the IC will cool it, but that will reduce the boost, and once you compress it again, the heat will come back. IOW, it doesn't really work.

inactiveuser92616

a mister could lower below ambient temp, that is how a swamp cooler works.