Do I have enough intercooler?
 

I have an older BEGI intercooler with about 6"x3" crossection and 12" core length. It works great on the street and has kept intake air temps well under control. I am hoping to get the car on track this summer and was wondering if this small intercooler will be able to keep intake temps in check on the warmer 90deg+ track days down in the south.

This is on a MSM turbo'ed low compression (8.7:1) 96 block with ~220whp. Assume fully ducted and sealed installation as well (still have to add all this).

Should be plenty. Bell cores are good quality with properly staggerred turbulators and internal air guides, as long as they're ducted such a core should be enough to cool your setup.

If you want the more complicated answer, hit up one of the discussions regarding proper sizing of cores and you'll see what I mean. Efficiency is important too, not just surface area.

This... hook up an IAT pre and post intercooler and figure out your IC efficiency at worst operating conditions (hottest track day). Or just figure what max IAT you're comfortable with a data log at your next track day. If it's too high either upgrade the IC or add some water meth injection.

I have been keeping an eye on IAT on the street and it looks good. I will be watching IATs after track sessions to see what I peak out at. That will be an indication if I need more intercooler!

The BEGI intercooler does appear to be of a better design and should be more efficient. At least that is what I am hoping.

What is the maximum IAT temperature to shoot for under boost?

What kind of driving conditions are we talking about here? Cruising around the streets with the occasional WOT pull? or 30 min track session where you spend 70% of the time at WOT?

Also, you're probably looking for a number over ambient or percentage of ambient temp. Off the top of my head I can't give you a good number but someone else here who datalogs their MS should be able to.

IIRC Andrew was always reporting +20F over ambient in Theseus.

20-30 minute track session are what I am concerned about. Even when considering temp rise over ambient there has to be some point that if air temperatures increase for a given boost level you will be more prone to issues. I can't imagine running with >>200 deg for extended periods being great for a forced induction engine. As you push the turbo out of the peak efficiency region air temps will begin to increase and get warmer the harder you push.

No way you are maintaining 20deg over ambient while in boost. That's one hella efficient turbo and intercooler.

That's what I see during a long pull in 4th or 5th and I have a shitty ebay intercooler. I'm not terribly surprised to hear that. On the other hand I was only making ~175whp or so last year. I seriously doubt you'll see anywhere near 200F, let alone over it. I think the worst IATs I ever saw were a JRSC at 8psi, IIRC it was well over 250F before the throttle body.

I tried to find it but could not. Hustler said to add 1 deg retard for every 5 deg F over 100. MS3 at least has that feature available.

It's totally possible with the proper equipment and proper airflow management. I have always seen about +25 on track with my own setup. Of course the heat loads in theseus were much greater than my heat loads, but that's why he had that giant intercooler and I can get away with my 28x7 eBay special.

andrew had proper ducting and a precision ginormous intercooler

+20 over amb on track is REALLY good, way better than most see

the most I've seen on a proper turbo setup on long pulls (on street) was 170-180
on the stupid FFS I saw as much as 230-250, and people track those too, so who knows how much our engines can really take. I guess pulling timing when it gets really hot is a good idea, but not too much unless you want to start melting stuff.

I think 1 deg for every 5* is way too agressive. you'll be -20 at 200 which would likely be in the negatives overall depending on your timing map, that's not good. that's how stuff starts glowing red lol

IIRC on Theseus, Andrew was running a Garrett 2871 right in the heart of its efficiency range and was pumping the boost through a ultra efficient Precision 600 and Gods ductwork. That intercooler is the size of a small house and weights about 30lbs. I know because its sitting in my garage. :brain:

Now that I think about people seeing such high MAT, your comment about pulling that
much timing makes sense.

Here is the thread, see post 7: Dyno tuning

EDIT:
Here is the quote: "Then, set your "IAT Related Ignition" and pull 1* of spark, per 5*f IAT>100*f. This will help stop detonation in the summer."

Guess it makes more sense for NA.

What makes sense for FI?

Water meth would help.

The main reason I have a a hard time believing 20 deg over ambient is that my NA setup before turbo would see more than 20 deg over ambient just due to engine heat. That is with an air filter and heatshield, not proper cold air pulling air from outside of the engine compartment.
Now Andrew's unlimited budget and Garrett 2871 is probably 10 times more efficient than the MSM turbo and BEGI intercooler I am running and was probably pulling ice cold air from outside the engine compartment. Now for the rest of us peasants that run affordable intercoolers ans smaller turbos it would be a different story and I would expect to see some temperature rise as the compressors add heat and intercoolers remove most (but not all of it).

We had a freakishly warm day the other day at 78deg for this time of year and I was doing some logging and noticed MAT was getting to 138 degrees constantly when doing long 4th or 5th gear pulls. Didn't seem to increase above this point even when doing several runs back to back. Within 10-20 seconds MAT drops right back to the 85deg I saw at non boost or cruise.

So lets say my setup can repeatedly show a 60 deg temp rise over ambients. Now assume I am running on a 100 deg southern track day. Will I be OK with 160 deg MAT? Hell, what about 180 deg accounting for nice hot air above the road surface?


I am not concerned with my setup at this point, but am trying to figuire out at what MAT temperature limit I need to be concerned about increasing the intercooler capacity or reducing boost to operate closer to the peak efficiency point.

I think you have to also take into account the size of your pump. It's gonna get real hot real fast cause the msm turbo is small, and not very efficient (compared to what's offered these days) since it's.....80's technology.

There's no way that you need any more than begi #3 for the stock ihi, I'd just work on ducting it and isolating the intake as well as you can so you're running as cool as possible.

I think you will be totally fine.

David, I think for n/a that would work cause as long as you're moving you likely won't ever see 180 temps. I think most cars I've done it's been something like 1 for every 20* or something, but my personal tables are non-linear when it comes to this: I usually don't start pulling til about 120*, and pull very little from 120-160 and then ramp up at 160-200 with max -5*

Vlad,
More thinking last night. Sure, with N/A, one does not tune those temps, but may see them on the street. With boost, you see those temps (100-150) on the Dyno so have already taken the AIT into account. The extra timing pull should be for when engine sees temps that were not tuned.

This morning, before I read your above post, I changed my settings to 1 deg per 20F starting at 100. Same max at 200 of 5 deg timing retard. Even though more agressive than you mention, I suspect the curves never deviate more than 1 deg timing at any point.

Thanks for responding.

OP:
1) Synopsis seems to be to not run boost in the inefficient region of your turbo when on the track.
2) Even N/A will see lower AIT if run through an intercooler after inducing hot, under hood air. Maybe not plain: Scenario 1: Ambient -> compartment -> manifold. vs Scenario 2: Ambient -> compartment -> intercooler -> manifold

I only have #1 BEGI intercooler. Thats why I asked the original question.

I am not pushing the little MSM to insanely inefficient regions of the compressor map, just beyond the peak efficiency region which for the little MSM is only 75%, I dont push it past the 65% region with the RPM and boost range I am using.

Another thing that a lot of people miss as being rather important for reducing post IC iats, especially in longer heat soaking conditions is pulling cold air through a low restriction intake tube pre-turbo. The cooler the air going into the turbo the cooler the air coming out, also the less pressure loss over the length of the intake tubing pre-turbo the cooler the air coming out (at the same target boost pressure since the pressure ratio will be higher at lower inlet pressure for the same target outlet pressure).

Here is a crappy pic of the current inter cooler. I really like the FAB9 stage1 intercooler with 20x6.5x3.25 core which is a little longer and has slightly more crossectional area than my BEGI#1 12x6x3. The additional length should help to remove more heat for track use. My biggest concern is that the really short 12" core I have now doesn't remove enough heat. I don't think I need anything bigger than this. Also, the FAB9 is advertised to be compatible with my existing BEGI inter cooler with minor modification which would be a plus.

I am also planning on modding the air intake to pull from a colder region or route cooler air to the current air filter location. I agree that the cooler air you bring into the compressor and the least amount of restriction has significant impacts on the air temperature leaving the compressor.

Fab9 Stage 1 PNP Intercooler - Miata 350hp

https://www.miataturbo.net/attachmen...1&d=1425739515

I ended up installing the exact same Vibrant intercooler that FAB9 uses for their stage 1 intercooler.
https://www.miataturbo.net/attachmen...1&d=1430324885
It is almost twice as long as my old BEGI intercooler and has slightly higher crossectional area. I was worried that the much larger intercooler would block the radiator opening and cause increased cooling temps, but so far I have not noticed a change in coolant temps.

Looking at the logs it seems that they both intercoolers would keep IAT's around 30-35 deg above ambient for most street driving. This would be the occasional 1-4th pull or extended 5th gear acceleration. I really didn't notice much difference at all, the Vibrant intercooler might have been a little cooler, but only bt 5-8 degrees.

When doing 3 or more back to back 2nd-5th hard pulls, slowing down and hitting it hard each time I would see IATs jump up a good bit more. The BEGI intercooler would jump 73 deg above ambient and the Vibrant intercooler would jump up to 60 deg above ambient. This additional peak above the normal 35 degree peak would only occur during the long acceleration runs in 5th. I don't know how often I will get to run 5th all the way out on track.

Based on my worst case track day ambient temp of 100 deg, maybe 120 deg above the asphalt, I would still only have IATs at 180 deg, definitely below 200 deg.

I would have expected a bigger differnce going from the tiny BEGI intercooler to the much larger Vibrant core, but the higher efficiency of the BEGI core does make a big difference. I noticed that the Vibrant core does not have any internal fin louvering and has a straight through air passage, great for low DP, but less efficient at removing heat. The BEGI core does have louvered internal fins and is probably why they are more efficient. Also the BEGI end tanks distrubute the airflow better.

Can anyone post some logged data from a nice hot summer track day session?

For the turbo miata guys that run out at CMP, what are your speeds coming into turn 1, turn 8 and right before the kink? I am wondering how long I will be pulling in 5th gear before slowing down on the longest straights.

What boost pressure is this? What estimated HP? This is for reference due to my gross ignorance. I'm kind of looking for what I might expect when I turn my boost up.

In 3-5th I am holding 14-14.5 psi of boost. Virtual dyno shows ~230 whp with just a little less in torque.

I want to try the same runs with 12-13 psi of boost to see if my IATs drop significantly.