agent712

The car is stock except for a Pettit intake and Racing Beat exhaust. Is a bigger intercooler a good idea on a pretty much stock motor? Will it help keep things much cooler? Will I gain any power? What one should I get?


Thanks
Chuck

jimlab

Much better idea. The stock "intercooler" is basically a big heat sink, and the plastic end tanks are a joke. A larger SMIC (underhood mount) is a good idea even on a stock car, since the more you can cool the incoming air, the better off the engine will be. The stock intercooler can quickly reach ridiculous temperatures under sustained boost, and it's so small that it almost immediately heat soaks when the car stops moving.

With a larger intercooler, there will probably be (depending on the model you chose) a fairly significant decrease in pressure drop across the core. What this means is that you'll probably see (once you buy a boost gauge) an increase of about 1 psi or so, which not only means more pressure, but more dense, cooler air entering the engine. Power will go up, but not by a huge amount. Power increases by about 1% for every 10 degree drop in intake air temperature, roughly. The extra boost won't hurt, and 1 psi is probably a 10-15 horsepower increase, give or take, on a car with stock exhaust.

Where it really helps is when you have provided adequate fuel to open up the intake and exhaust. At higher boost levels, your turbos won't have to work as hard to produce the desired intake manifold pressure level, and the intercooler will really pay off in keeping intake temperatures down as the turbos exceed their most efficient range. That's when you'll see the biggest power gains, with open intake and exhaust, and 12-13 psi.

I have only one recommendation based on personal experience, and that would be the M2 Performance (formerly ASP Racing) medium SMIC. It's one of the most efficient intercoolers available for the RX-7, but you may run into problems if you keep the air pump and the stock battery, although it is said to fit with both. Also, it's about one row too tall, unless they've changed the core dimensions, and can rub on the underside of the hood. Crooked Willow had a tilted intercooler of roughly the same core size, but I don't know that they ever got the ducting finished. SR Motorsports also had a "flat" mount intercooler, but it has apparently been discontinued.

SR Motorsports intercooler...



M2 Performance medium intercooler...

agent712

Sounds like he should start saving for one then...
A good intercooler on a car w/ basics like a pettit intake and good cat back should see gains of about how much do you think? And what might this car make power wise at the rear wheels?

Thanks
Chuck

agent712

Just took the car for a spin. After getting home I popped the hood and the heat is incredible. I DO NOT like where the intercooler is mounted. Right above the radiator is NOT a good place to cool anything. Especially an intercooler. So, does anybody make an intercooler setup for this car that mounts somewhere that isn't effected by the heat of the radiator? Something that works in conjunction with a body kit or whatever? As far as I'm concerned the factory intercooler location is actually an interheater! Suggestions?

Thanks
Chuck

Mahjik

iTrader: (1)

Do a search for "FMIC". You should find some pics of Front Mounted Intercoolers here in the forum. However, with front mounts, unless they have a special duct you'll lose some airflow to the radiator....

Unless you plan on upgrading the stock turbos, the standard location is fine for an IC unless you just want "the look" of the front mouts. Just get an upgraded one like the M2, Blitz or GReddy and you'll be fine.

agent712

Ok cool, which one is the best bang for the buck? And what kind of gains would I see over the stock one?

Thanks
Chuck

Johnsrx7

You can also get a vented hood to help with a SMIC as well.

Mahjik

iTrader: (1)

It really depends on the amount of work you want to do. Check this thread, there is a lot of good information about SMIC's:

https://www.rx7club.com/forum/showth...threadid=81194

As far as gains, the IC in itself isn't really going to give you anything. It will allow the car to run higher levels of boost safer. Some people say they experiece a little more power and/or less heat soak, but it varies.

agent712

Hmm, ok, thanks for the help!

Chuck

weaklink

There is stock ducting in the nose that routes air to the SMIC.

agent712

Hmm, ours does not have this. Could that cause big problems in performance?


Thanks
Chuck

agent712

ttt

rotorbrain

your stock intercooler doesnt have the duct? man, thats not good at all. you could have some detonation problems too. get an intercooler quick. if you want one that goes with the stock location a little better check with spyfish007. it is one of the best for the fit and the money. it is an smic. just depends on what you are gonna do with the car and what look you want. . . but you must change it or you will have problems. that intercooler is cooling with radiator heat. so it is just heating up. not good at all.

agent712

Wonderful, just what we needed to hear.


Thanks
Chuck

jimlab

Not to worry you further, but the stock duct not only directs air to the intercooler, it also directs air to cool the battery, the A/C cannister, and to the intake box. If you don't have the stock duct, you should probably think about getting one in the near future if you won't be upgrading the IC soon.

Check the For Sale section, someone has probably replaced their air box and intercooler and may have the stock duct for sale for a reasonable price.

Mahjik

iTrader: (1)

Chuck, can you remove the front cover and get a new picture?

It sounds strange that the car doesn't have the IC/Battery air duct....

CrispyRX7

iTrader: (139)

My input.
A CWR IC with CWR intake

Regards,
Crispy

agent712

I took the cover off and there is not any sort of duct running air to the intercooler at all. Just open air between the intercooler and radiator... not good. Any suggestions? Could this be why it's so slow right now?

Thanks
Chuck

Nathan Kwok

Yeah that's going to hurt things. Definitely do something, either get a stock duct or an aftermarket IC that comes with a duct. I'm sure you can find a stock duct for very cheap, probably $50 or so, just look around. See the other threads regarding an upgraded IC.

jimlab

Well, it's slow because it's an automatic, but having the intercooler duct missing sure doesn't help.

The thing I wonder is why it was removed. It's not something you'd remove unless you got an aftermarket IC (which you obviously didn't get with the car) or unless the car had some light damage in the front and they just didn't replace that piece for whatever reason. Have you run a CarFax check on the VIN for the car?

agent712

Yes, we ran a Carfax of the car. It's got a clean history and doesn't appear to have had any damage to the front of the car... The guy we bought it from lamotorcars.com did tell us it had some modifications that he took off and put onto one of his 5 speed cars though. So maybe it had an aftermarket intercooler and just through this one on. That's probably it... Either way though, I'm pretty sure I'm not going to put on the cai and exhaust until we have the intake temps down to where they should be... Anybody ever tried watar injection?

Thanks
Chuck

93TTRX7

i've heard water injection wears out seals...i was told this by Jeff at Rotary Power

agent712

I don't see why because almost all the water (which is a mist that is shot into the intake duct) is evaporated by the time it gets to the combustion chambers (or whatever you guys call them on the rotary)... so I don't see how it could effect seals at all. I can see how misting a jet of water into the intake duct on a turbo car would greatly reduce intake temps though. You could even use a water/alcohol mix to run higher boost on pump gas. Great little investment in my opinion for less than 400 bucks.


Later
Chuck

agent712

Here's a link to some good information on what and how water/alcohol injection works... http://www.geocities.com/rad87gn/tech/alcohol.html


Later
Chuck