how is a junkyard intercooler neccessarily going to be better than the stock mazda unit?

 

Have you measured the core on a stock FD intercooler? Without looking I'd guess its maybe 6 high by 10 wide by 3 deep at most...I have a volvo unit sitting at home that would work better, but of course you'd have to cobble up some ducting. Actually the big *** diesel turbo intercoolers are HUGE, a popular upgrade thats reasonable sized is the mitsu Starion chrystler Conquest units.

 

$150FC because they are bigger!!

 

While that is true, you're overlooking the issue of the heatsoak the stock intercooler has to deal with...which will definitely affect the temperature no matter how efficient the compressor.

 

Is that t78 godzillas former FD by any chance?

 

It is my old car, right before I sold it I took it to pettit to have a wiring harness changed because the old one was destroyed and he put that ic in it *Had a pettit coolcharge 3* and tuned it and said that was teh best intercooler for 10lbs of boost efficecny wise. I found this rather fishy but decided not to ask questions. The car runs like a scolded *** ape the way it sits and if cam says the stock ic is good for 10lbs on that turbo I wont argue for he knows more than me.. *hopfully*

Matt

 

why build a t78 single turbo rx7 with a half bridgeport and then only run 10 psi through the stock intercooler?

you should be running a few more pounds with a better intercooler!

 

i was thinking that the whole time and was hoping i'd be the first to say it.

and what's this crap about heat soaking the IC. if the charge air temps of a T78 are cooler thant he stock twins then the chance of heat soaking the IC are less. i don't see the problem at all. everyone sees T78 and stock IC and thinks OMFG he's gonna blow it up!!!! 10psi is 10psi. if the motor can take 10psi of hot stock twins air, then it will surely take a cooler 10psi charge from a T78. what's the big deal. some people just get all worked up over the stupidest crap.

ok now, people with completely stock FD's put on boost controllers right? what boost do they run? for example, if they go around running 15psi on the stock twins then i believe you can run a little more boost with the T78 and not have any problems due to the cooler charge temps. as long as you don't blow off any pipes. am i leaving something out here??

 

heat soak doesnt occur because the turbo is hot, it occurs because the engine bay is hot. Bigger intercoolers take way less time to recover from heat soak. Also I dont see how a stock IC flows more efficicently, flow is based on the number of available "rows" for the air to flow through...

Also the turbo is probably working harder to push air through it, which will increase the ammount of heat added. 10 psi is only 10 psi when the motor is flowing at a given efficiency. With the T78's large exhaust and a 1/2 bridge that thing is flowing a TON more air at 10psi than a stock car.

 

well, yeah, it's getting a bunch more air cause of the bridgeport, not the turbo. either way, given the same motor, swapping the stock twins for a T78 will yeild a cooler/denser intake charge.

and i didn't say the stock IC was efficient. and someone stated that it is at least a flow restriction.

i'll agree tho, get a FMIC and turn that boost up. i just don't see anything wrong with what he has now.

 

actually its "getting a bunch more air" because a T78 at 10lbs flows a lot more than stock twins at 10 lbs

 

umm, no it doesn't. not for the same motor it doesn't.

 

You are saying a T78 doesn't flow more than stock turbos? Yeah that sounds about right...

 

That's what I was thinking.
Either up the boost with a better intercooler, to where the T78 is REALLY efficient, or get a better suited turbo for low boost.

 

Don't know much about turbos do you? 10 psi is 10 psi huh? There is something you are totally forgetting about. It is flow rate in CFM. I am going to just make these numbers up to get the point across so don't think these are actual flow numbers.

Turbo A flows 500 cfm of air at 10 psi.
Turbo B flows 400 cfm of air at 10 psi.

It is obvious that turbo A is flowing much more air. Let's alter these a little bit and say that :

Turbo A flows 400 cfm of air at 7 psi.
Turbo B flows 400 cfm of air at 10 psi.

Now they are flowing the same amount of air. You show me how the motor it was sitting on makes a difference. Don't even compare stock twins to a single on a bridgeport. A bridgeport engine has so much overlap that it needs a really free flowing turbo exhaust. The stock twins are so restrictive that alot of the exhaust will back up around to the next intake phase and dilute it heavily. The engine can't flow more air if the turbo can't.

Pressure is not what counts. This is because we have 2 forms of compression. The first is the compression number that we know as the actual compression ratio. 9:1, 8.5:1, 9.4:1, etc... The 2nd compression ratio is the effective compression ratio. This is what the engine sees. This is determined by how much air is entering the engine. It is the amount of air entering the engine and not the pressure it is at that determines how much power potential there is. Notice we tune for a specific air/fuel ratio. The air part of the formula is for the amount of air. The pressure it is at is irrelevant. It doesn't matter if it is 400 cfm at 7 psi or 400 cfm at 10 psi. The amount of air is the same. There are other factors such as heat, timing, etc that I am purposely leaving out just to get the point across.

 

Turn the compressor housing so it outlet is facing down. I think that would make a much better angle to go to the inlet of the IC. Maybe move the ast to the right side. Get that badboy compression checked and tuned again just to make sure its ok dont trust just anyone on its condition.

 

There is so much disinformation on this site, heh.

Just because an intercooler is LARGER does not mean it cools better or even flows better. A well-designed intercooler that is smaller than a bigass diesel truck intercooler can work better for a given setup.

For instance, some dude mentioned the Starion/Conquest intercooler. That core is a poor flowing, poor cooling core - it's been tested against a number of other stock intercoolers from various turbocharged japanese cars.

I am not saying a front mount wouldn't help (it would), I am just saying that the stocker does its job well enough when it's not pushed beyond its capabilities and you cannot haphazardly throw an IC on and expect the best performance.

 

Squirt a load of methanol into the mix and find out exactly where the stock IC will come apart.

 

Something you're forgetting is that if you don't change anything else on the motor, your still working with a constant volume for a given rpm. This has been discussed at length before, search on it. You can't just magically flow more air into a constant volume closed loop system without changing stuff -ie turbine housings, ports etc.

 

I used my stock intercooler while I was breaking in the motor, but never saw more than 5 lbs of boost, and only then on a few brief occasions. This was with a T78 and street porting.

I went with the PF Cool Charge III IC, and my intake charge was nice and cold, even after full boost runs at the track. The IC is actually larger than most front mounts.

Best do something or you will have detonation.

 

I understand where you are trying to go with that one but you'd better think a little harder about that.

 

boost pressure is nothing more than backpressure in the intake. if you try to shove more air into the same size hole, then pressure goes up. if you have the same size hole, and the same pressure, then the cfm's stay the same. simple physics.

oh, and correctly written, it's static compression and dynamic compression.