wouldnt it be more eficient to use a intercooler even with a carb setup.? i heard somthing about the charge pipe not getting that hot because of fuel atomization in the turbo? whats that all about? and also that the intercooler could get oil inside it how is this even possible?

 

intercooler could get oil if you used a draw through setup. Sometimes people opt not to have one on budget or low psi turbo builds. I myself used a massive intercooler which cools the air nicely but i suffer a little because i don't see boost until 4 grand cause of the huge intercooler.

 

There are a couple reasons.....

On draw-through systems,you dont want fuel building up in the IC after it leaves the turbo,so that leaves only blow-through systems as a IC candidate.
Many guys are only running in the 5-8 psi range,which makes charge air cooling un-needed.Sure it will help a little,but the gains are often not worth the cost and work of plumbing it all.
Plus,with the carburetor far upstream of the engine,the evaporation of the fuel on its way to the intake ports,has a greater cooling effect on the air compared to injected engines which shoot their fuel right as it enters the ports.

 

^well said

 

What he said. amd most blowthrough guys are on a budget and intercoolers and the extra coupleings and pipeing aren't worth the extra 10whp, not until you decide to turn up the boost past 10psi.

 

I had a carby turbo setup. Heres some of the reasons they dont have intercoolers.

1. money, if they had alot of money EFI would have been used.
2. most carby turbo cars are drag raced, dont need an IC for 12 second runs.
3. money

I ran 12psi on my setup. made 250RWHP and would do 12 second quarters on a stock motor. I could run it through the mountains full out for 15 min before the intake charge would get to hot, which you pull over and stop for a bit or just cruise and boost little as possible.

 

sorry to revive an old thread, but i'm always looking for new plans lol. here lately i started looking into turbos, not exactly sure how they work. up until last week i didn't know they worked off the exhaust..which is confusing itself lol. anyways, i want to know the main differences from draw through to blow through? all i got so far is that draw through uses i/c and blow through CAN use an i/c but don't have to... ....sorry i know nothing about boosting lol. (i know this is an extremely noob thing to ask and i wont get pissed for any noob remarks lol, i've admitted it, i know 'nothing' about boost)


kinda interested in turbos, it'll definitely be a while before i do anything like that to my car, but just trying to get research so i know exactly what i want, plans thus far are (once i find someone to do it, and i have the cash) a street port, of course bigger intake and what not, that i'm not sure just w/e i can get my hands on, holley or weber, full exhaust (mainly headers, once i get around to that depends on what i feel like lol) rebuild the engine (it's getting up there hopefully it'll last me a long time lol 129,000 miles on it, and as far as i know it hasn't been rebuilt haven't been able to get a hold of P.O.) well with the rebuilt, seals and all that good stuff, enough to handle the street port, and maybe boost......unless a stock port engine can handle small boost, i don't want anything too big just something small that'll make it a bit faster (i would go with a bridge port.......that's another thing i'd have to wait and see once i finish all my research of what i want).

 

http://en.wikipedia.org/wiki/Adiabatic_compression

Add 460 degrees to the temperature in fahrenheit to get absolute temperature (Rankin). i.e, -460F is absolute zero. Add 14.7psi to the gauge pressure to get the absolute pressure. So the intake air before the turbo is at 14.7psi. Adiabatic compression means no cooling, so this will tell you the temperature of the air coming out of the turbo without an intercooler. Power is directly proportional to absolute pressure and inversely proportional to absolute temperature. With an intercooler the temperature will be somewhere between the outside air temperature and the temperature after adiabatic compression. Now you can figure out about how much power an intercooler would give and if it's worth it.

I'm not buying the comments about drag racing and short drives. The compressed air reaches the appropriate temperature the instant it gets compressed. The only thing keeping it cool during a drag race would be the "cold" piping and engine, and I can't imagine those having much capacity to absorb heat nor ability to remove heat from much beyond the air that's right against their surface.

 

I'm running a S4 turbo on my 12A blowthrough with a modified Nikki and intercooled. I am running at 15 psi right now. Check out this thread on my buildup. https://www.rx7club.com/showthread.p...roject+updates Do your homework on this, because doing a blowthrough can make alot more power than drawthrough.

 

i wanna see close up pics of your set up...from exhaust/turbo/ic/ to the carb, if you don't mind. i'm just trying to get an idea of how everything looks and works. how much boost can a stock port hold? i wouldn't really wanna do drawthrough cuz i don't like the idea of not having an i/c.

 

Port size has nothing to do with it. Intake temps, octane, and tuning ability are what matter.

 

Only so much air you can force through a small port at a given time.

 

how about all the internals? will the stock apex be able to handle very light boost, idk say 5psi?