[///mfizzle]

Hey guys,

I've searched but can't really find any answers from people who actually road course there cars. I do track days every once in a while at sebring raceway in the summer, as you can imagine intake temps get pretty hot in a 30 minute session. I was wondering if I should go with a 5" stpped intercooler or a 7" intercooler? And what do you guys have?

My car is on stock turbos with no power mods other than charge pipe and tune. Hence the reason I wasnt sure if 7" would be overkill with pressure drop. I have no plans to do anymore power mods in the future.


Thanks!

[Silent9n54]

The biggest one you can afford. Dont cheapen out on the fmic, especially if you are planning on tracking the car.

[whyzee125]

It gets hated on sometimes but the CXracing is the best intercooler. It's absolutely massive, looks amazing, and does an incredible job of cooling with no discernible lag.

[Moisture]

I would recommend fabricating some sort of hood vent like you see in the picture, towards the front of the hood. I would honestly just use a dremel tool to cut open a square and lift the exposed metal up facing towards the windshield sort of acting like a vented flap. This is going to help increase radiator flow while removing much of the heatsoak you might find going on underneath the hood. In my opinion this is crucial for BMW's because they run so hot, even if it is warm outside and you are driving normally!

[Hxngs]

If you're gonna track. Even if it's once in a while. You might as well get the 7in.

[sky82]

Vrsf has the regular street 7.5 and then they have the race 7.5

I know bigger is better but would the race be overkill?

[///mfizzle]

Originally Posted by sky82

Vrsf has the regular street 7.5 and then they have the race 7.5

I know bigger is better but would the race be overkill?

I think the regular 7.5 is better for stock turbos. That's what I'm leaning towards now.

[WatchWolf34]

Interesting opinions here...

I run the ETS 5" with my stock turbos. It works fantastically and my car is a daily driver in the spring, summer, fall and I track it about 7x per year.

People will say bigger is better but that's just not always the case especially with stock turbos and stock boost levels. Quality over quantity.

[///mfizzle]

Originally Posted by WatchWolf34

Interesting opinions here...

I run the ETS 5" with my stock turbos. It works fantastically and my car is a daily driver in the spring, summer, fall and I track it about 7x per year.

People will say bigger is better but that's just not always the case especially with stock turbos and stock boost levels. Quality over quantity.

Yep that's exactly why I was asking, I feel like a 7.5 is overkill for stock turbos and stock boost levels, In theory wouldn't the turbos have to "work harder" to make up for the extra pressure drop with the bigger intercooler?

how do your intake temps do during the track days with the 5"?

[Torgus]

Originally Posted by ///mfizzle

In theory wouldn't the turbos have to "work harder" to make up for the extra pressure drop with the bigger intercooler?

It will barely be noticeable. The gains from having a better intercooler far outweigh the volume increase. Most people don't even notice going from stock to say a 7.5'' race IC. The stock snails spin up VERY fast. They also produce a TON of heat. Hence the stock IC being useless.

As far as CX racing, get the 4'' thick version, not the 3.5'' everyone seems to buy if they still sell it. You have to call and ask it is not on the website. IIRC the 4'' is like $475? 3.5'' is $420 https://www.cxracing.com/KIT-N54-E92-IC0047-E9 Getting very close to the cost the the BMS or VRSF 7.5'' race intercoolers.

The VRSF race is 3'' in and out vs. 2.5" Inlet & Outlet with the CX racing. Not a big deal unless you are shooting for big numbers. The big difference is weight. CXRacing is 18lbs vs VRSF 45 lbs. That is a HUGE difference in favor of VRSF.

I vote get the largest you wallet can afford.

[bbnks2]

Originally Posted by Torgus

It will barely be noticeable. The gains from having a better intercooler far outweigh the volume increase. Most people don't even notice going from stock to say a 7.5'' race IC. The stock snails spin up VERY fast. They also produce a TON of heat. Hence the stock IC being useless.

As far as CX racing, get the 4'' thick version, not the 3.5'' everyone seems to buy if they still sell it. You have to call and ask it is not on the website. IIRC the 4'' is like $475? 3.5'' is $420 https://www.cxracing.com/KIT-N54-E92-IC0047-E9 Getting very close to the cost the the BMS or VRSF 7.5'' race intercoolers.

The VRSF race is 3'' in and out vs. 2.5" Inlet & Outlet with the CX racing. Not a big deal unless you are shooting for big numbers. The big difference is weight. CXRacing is 18lbs vs VRSF 45 lbs. That is a HUGE difference in favor of VRSF.

I vote get the largest you wallet can afford.

How is weight an advantage?

I personally track my car with a 5" and I'm fine with it. Worst iats I've ever seen was at pocono raceway when it was 96f outside. I hit 17xf while topping out 5th gear. I dont see that high of an iat at any other track. In perfectly happy with that as even 17xf is not bad at all. I usually see 14xf at other tracks with shorter straights like Lime Rock.

I'd rather have the lighter/smaller 5" intercooler than a 7.5 that weighs 45lbs. Iats arent as important as ppl make them out to be. The car hits 200f+ on the street with the stock intercooler and the world doesnt end. Just dont tune the car to the ragged edge of knock with 70f iats and then hit the track... that will result in lots of knock. If it bothers you that you're leaving 1-2* of timing on the table because your iats are 20-30f higher than they could be with a bigger intercooler than get the bigger intercooler.

I am n55 with a ps1 turbo tuned to 90%+ wgdc just for reference. I also like running e85 tune at the track. I am tuned for e40 but put in closer to e50 on track days to have the increased buffer of knock resistance.