shm21284

Sorry to sound harsh, but the big *** B_U_L_L_S_H_I_T pissed me off

rotary emotions

12A draw through RX-7's are not uncommon at all. The UK specialist Elford made a nice kit, developing 160hp, and more if you tweak it a bit.
Draw through turbo's used to be very common aftermarket installations in Europe on Ford V6's before the EFI systems came.
Icing isn't that much of a problem. Actually the draw through setup isn't bad as such, but you just can't make as much power (no IC, no BOV...) as a well developed blow through, or even better a modern EFI.

85rotarypower

Well, most people that do a drawthrough are probably not looking for a great amount of power, but I think a drawthrough turbo setup would be capable of 250hp easy if its tuned right. Thats more than enough power to put a 1st gen into the low 13's in the quarter.

Read the rest of the thread, and I stand corrected on many subjects. I'm just talking from my knowledge, so if I'm incorrect on something I'm sorry. Looks like my knowledge of physics isn't as much as I thought.

nevarmore

I'd like to add in what I know about fuel igniting, kinda goes along with what nkeehn said.

You need the fire triangle to get something to burn, air, fuel and a spark. To get gasoline to spontaneously combust (burn really fast) you have to make it a fire square and add in compression.

Fuel doesn't ignite in the fuel rails because there is no air and a spark is unlikely. I think its also still less than the miniumal pressure for spotaneous combustion.

The air fuel mixture in a draw through set up COULD ignite, but its generally not under enough pressure to spontaneously combust. If it did ignite you would probably have a very slight rise in pressure and your engine would be getting a fireball instead of fuel and air. Your turbo wouldn't be happy either. It would be bad, but not catastrophic.

85rotarypower

I kind doubt that it would ignite in the intake track. There just isn't enough compression there. But I don't know if I should say anything because I've already been proved wrong once in this thread.

nevarmore

You have fuel and air. It can ignite as in BURN, but it won't spontaneously combust/explode because it is not under enough pressure.

85rotarypower

When I said ignite I meant explode as in what happens in a combustion chamber.

Oh Yeah, nevarmore, I wasn't refering to your post in a bad way. I was agreeing with it. I think I will just shut up now. This is the most anyone has ever quoted me in a bad way before.

shm21284

Dude, the air/fuel mixture in the intake manifold is only under 15 psi of pressure. if air/fuel doesnt combust under 165psi, why would it under 15psi? please explain, i dont understand your argument.
I ran 18psi with no problems. I have heard of 23 psi with no problems. There is absolutely no way for the air/fuel mixture to ignite unless spark was introduced or somehow the compression jumped to the 200 psi range, where it would start to ignite like a diesel (from compression).

shm21284

Basically, what i am trying to say, is that the common misconception with draw throughs is having to run low boost. You can run more than enough.

Sterling

I don't think there's much doubt that a draw through turbo will work. Certainly here in the states all you ever used to see of supercharged systems were draw throughs. In fact, they still use this approach as OEM design.
But with very little extra fabrication and money, you can have a much more efficient blow through system that will yeild a great deal more power, and even have the potential to prolong engine life if you set it up to only have the same power as a comparable draw through.

The application of a turbo in draw through configuration is the same "old school" ignorance of science that has given supercharging a bad rep. Draw through is an archaic approach to boosting when there are yards filled with parts that will make a blow-through system only 10% more work, yet yield 25-40% more power.

shm21284

I am converting to blow through, front mount intercooler, fuel injection, and stand alone computer. I just thought i would post my project thus far, and how it worked out, etc. I need to post pics of it so people can see it.

Sterling

Can you keep track and tell us the added cost to convert it?
Pictures would be cool.

85rotarypower

Look at the pro drag cars. All the ones that run blowers have the carbs ON TOP of the blower, therefore its drawthrough. Any carb with a supercharger is set up this way when talking roots type superchargers. Centrifugal superchargers are set up like turbos most of the time though with blowthrough. This is because they work like a turbo without the exhaust side of the turbo.

red13brx7

Hey I am doing the drawthrough set up right now in my car. I am using an 86 6-port with the racing beat carb, a little modding to do to that, with the stock second gen turbo and I am going from there. I will show you some pics when it is done.

zenjoe

look at all the aircooled vw turbo guys, most run a draw through turbo setup as opposed to a blow through. These guys are makin in excess of 600hp at 30+ lbs of boost.

therotaryracer

Draw Through = power for the buck. You need not to spend 1k on a intercooler and can install water injection to cool the air at the expense of little HP. this thread is old but thought of commenting to see if anyone knows of Draw through setups that really produce alot of power and what turbo they are running. I have ran a blow through and draw though and both were fun, though the blow through seems alot more like show once on the road it really gives a kick, but driveability the draw-through was amazing.

Algod

i was driving home and i suddenly lost all my boost. i had flooded the engine two nights before and my friend said i might have carbon siezed the turbo. when i took off the piping i notice a lot of carbon. and when i tried to spin the turbo it would turn a little then get stuck. how do i clean this or fix it so can have boost again.

TurboFB

That, and you don't need to jump to conclusions when you don't understand what somebody is trying to interperate. Hmm...kind of like this...