matty

I have been contemplating buying an intercooler...help me make my decision. My thinking now is that unless you road race (track) a car or run anything over 12.5 psi an IC really isnt needed. I am thinking that at 12 psi the stock ic will yield the same rwhp and 1/4 times as 12 psi w/ a large after mkt ic.

I really dont plan to track the car. but do drag race.
My thesis is i will only benefit from an IC if i run more than 12 psi. Is this correct?
matt

Freaky Monkey007

Is this on stock twins or a larger single or hybrid twins?? It all depends on what kind of turbo(s) you have..

matty

stock twins
mods are full exhaust, intake, power fc
1/4 time= 12.724@ 111.5 mph
296.5 rwhp (intake air temp was high)

Red Rotary Rocket

No. The large IC will give you HP gains even if you only run 7 psi. There are two reasons for this.

1. Less pressure drop across the upgraded IC means the turbos don't have to work as hard to produce boost, which means less exhaust backpressure and more power.

2. Even at stock boost levels, the stock IC heat soaks really easily and isn't as efficient as an upgraded IC. No matter what boost level you run, the upgraded IC will give you cooler air temps, and higher HP.

Hope that helps.

Freaky Monkey007

Actually a large FMIC unit will have more pressure drop than the stock unit. A SMIC wouldnt have as much pressure drop but it would still be more that the stocker i believe. The larger area inside the IC is what causes this.

RX7Elmo

i'm not sure how common this happens, but i'd be fearfull of the stock IC plastic tanks cracking or popping off. And at 12psi the stock IC will heat soak to hell and and you will have really high intake temps, which can cause denotation.

Red Rotary Rocket

You may be right about the FMIC, but this is not true in the case of an upgraded SMIC. Sport Compact Car measured the pressure drop across the stock IC and the M2 Medium and M2 Large as part of their project RX-7 series. The M2 Medium and M2 Large both have a smaller pressure drop than the stock IC. IC size is only part of what determines pressure drop. The design of the core plays a large role, and in the case of the stock IC, the core design basically sucks.

matty

actually my intake temps stay around or under 50 degrees when cruising in the summer...obviously in summer traffic things are different.

Red Rotary Rocket

The temps you see while cruising around don't really mean much, because the turbos aren't boosting when you are cruising around. The turbos don't heat the air much unless they are producing boost. If your stock IC is giving you 50 degree intake temps while cruising, think how high they'll go when you decide to have a little fun. As an example, last summer, while doing some spirited driving on a 100 degree summer day, I saw intake temps of 90C at 10 psi and the stock intercooler! 90C is just way too hot.

ttpowerd

Actually you are both right. THe FMIC will have more pressure drop than a SMIC and the m2 units have even less than the stocker. The biggest problem with the stocker is the size (heatsoak easily) and the plastic endtanks (crack, pop off).

Wade

iTrader: (1)

IMO an intercooler is money well spent. You won't pick up much power all else equal, so don't expect your 1/4 time to improve. And a large IC will heatsoak in a staging lane just like the stock IC.

However, under most circumstances, a better IC will give you cooler intake air and a little less restriction, which will help power a little and reduce the chances of knock. I think the stock IC is really undersized and I'd recommend an IC to just about anyone.

Wade

RX7withNitrous

more air/colder air ( caused by FMIC) = HP BABY!!

RX7withNitrous

regardless of boost you might gain more hp with higher levels of boost but you will still gain hp. Oh i was going to ask who makes good FMIC's for fd's and how muchg are they?

RyanREX

I'd go with SR motorsports smic

PVerdieck

IF you really want to find out, don't be lazy.

1) Read this
https://www.rx7club.com/forum/showth...ch+intercooler

2) Go to the 3rd Gen Archive and look at the topics and read.

Back to my 1st point. You ask the question and think you will get the right answers.

Yes, you will get some good advice.
No, you won't get all the right advice. This question, and virtually every other one, has been asked so many times, that some of the more advanced/experienced member here aren't going to go into the detail that they have done before, because you are too lazy to spend 10 minutes searching and look around.

This forum is a wonderful resource. Using the proper tools (LIKE SEARCH) is the best way to make use of this resource.

There is a common PC/IT acronym known as RTFM. That means Read The ******* Manual. The analogy here is use the search function.

You asking specifically about pressure drop, and you have posted before, so parts of this flame might be overboard...

Just about everything I have read here says that the stock intercooler is a piece of crap. It is too small. Any after market unit will do a better job of lowering temps, making the turbos more efficient, and give you more HP.

maxcooper

I think you can get the lowest pressure drop with a big SMIC, but it seems likely that you can also get a decent reduction in pressure drop with an FMIC. FMICs typically have longer piping with more bends and less room for a lot of internal flow area as strikes against them, but that doesn't mean they will be worse than the little stocker. An FMIC core could offer good efficiency with a less dense (and thus less restrictive) core because they are typically longer than a SMIC.

You will get a decent power boost from a good IC, and lower intake temps are likely good for the engine, too, to reduce heat load and lessen the chance of detonation.

One thing I noticed when I temporarily switched back to my stock IC for some testing was that boost response was noticably improved. The smaller volume of that setup means that it pressurizes more quickly. I was surprised how much difference it made. This seems like another advantage for SMICs (less overall volume from shorter pipes), but I have warmed up to FMICs generally after having trouble keeping intake temps low for tuning on the dyno with my SMIC.

-Max

Kahren

iTrader: (13)

the intercooler by itslef doesnt give you any horsepower teh air that it cools down does, since you can get teh air cooler u can now run more boost and that will have an impact on yor HP and stock intercooler is not a great piece to begin with, if you have money to spend an intercooler woudl be a good upgrade. and assomeone state before, you shoudl really search, there has been plenty of argument about this, if you woudl like to find out more the information is a few clicks away. i dont see how anyone would write a big description of how somethign works if they have done that before about the same topic.

jspecracer7

50 celsius? I would do consistent runs from 1st to 4th gear back down and then up close to 5 times in a row boosting 1.0 kilos+ and my intake air temp NEVER got above 45 celsius. This is during 95 F summer days in Okinawa.

matty

ummm....which IC?>

grampa

This is why I have retained stock size with an ARC intercooler. It is much like the stock in external size but the internal passages are larger. When painted black it looks just like the stock one. I then installed an aquamist water injection system to make up for lack of cooling when boosting.

The best of both worlds - quick response with decent cooling.