Why It Pays to Replace the Intercooler While Servicing the Timing Belt | Project Toyota MR2

Any car enthusiast who’s ever turned a wrench knows the pain of “as long as I’m in there…”

You begin one process with a plan and realize halfway through that you’re close enough to some other processes where starting the job over wouldn’t be worth the effort.

That’s how our 1991 Toyota MR2 Turbo ended up with a new intercooler soon after we started to replace the timing belt.

Even though our Gen4 3SGTE engine was never official brought to America, finding parts is still easy thanks to an enthusiastic community of supporters.  Prime MR2, who originally built our swapped car, sells a complete kit containing all of the front-of-the-engine maintenance items that you’ll replace during the timing belt service. This $415 kit consists of an OEM or premium aftermarket timing belt, water pump, idler pulleys, tensioner, cam and crank seals, oil pump o-ring, and all necessary gaskets that you’ll use when performing the service.

It does not include bandages and a profanity-to-English dictionary that are also necessary when working in the tight space between the engine and the right side of the engine bay, but patience and tenacity will pay off in the end.

In Japan, most of these JDM powerplants are taken out of service around 100,000 kilometers, which is why buying JDM powertrains is relatively simple in the U.S.

Based on a sticker on our cam cover, we think that our timing belt was serviced at around 93,000 kilometers, but we don’t read Kanji, and we also wanted to know exactly what we were dealing with as we began modifying the engine for more power. And even if our belt was low-mile, it was certainly high-time, having spent at least five years with us and who knows how long with its previous owner.

Once we had the covers off the front of the engine, though, we were impressed with the absolute lack of any oil on any of the surfaces. We opted to leave the existing cam and crank seals in place under the “if it ain’t broke, don’t fix it” clause.

Our stock intercooler wasn’t broke, either, but it needed to come out to properly access some of the fasteners. While an upgraded intercooler was definitely on our list of eventual mods, we hadn’t planned on replacing ours until further along the process. But it also seemed silly to go through the hassle of removing ours, only to put it back on then take it out again later. It’s not the hardest job in the world, but it’s also not something you want to do twice if you can avoid it.

So we lit up the phones to see if we could locate a new intercooler in a timeframe that wouldn’t slow our job too much. Luckily PrimeMR2 came through again and was able to get us a complete kit including an upgraded intercooler, shroud, upgraded fan and proper piping for our Gen4 engine shipped directly from TCS Motorsports and delivered within a few days. This $500 kit also includes the silicone connectors and high-quality T-bolt hose clamps you’ll need for installation, making it a complete solution for upgrading.

While we haven’t yet been able to dyno the car in its current configuration, there’s zero doubt that intake air temperature is an important factor in making power for a turbo MR2. When we were doing some baseline dyno runs at BSI Racing, we took a moment for a little experiment: We did back-to-back runs with no modifications other than spraying down the stock intercooler with a little cold water. The result was an instant bump of 4 horsepower and 5 lb.-ft. of torque, all merely by lowering charge temp.

With our engine’s breakable bits freshly serviced, and a little unexpected power bump, we’re looking forward to getting it back on the dyno and to the test track to quantify our work.

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Comments
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crankwalk (Forum Supporter)
crankwalk (Forum Supporter) SuperDork
1/25/21 12:04 p.m.

Snorkel time. smiley

wspohn
wspohn SuperDork
1/25/21 12:07 p.m.

Does that IC get any air flow without the fan, or is it exclusively fan driven?  Is there a failsafe that tells you if the fan fails?

I've always preferred an IC that has ducted forced flow and in some cases (my Fiero that I turboed) I opted to keep the boost no higher than 10-12 psi as there was no way to mount an IC without butchering the car .

You engine bay looks pretty full. Although there have been systems that mount a turbo at one end and the engine at te other end of the car without undue lag, I don't know if running a duct all the way to thr front and back to a front mounted IC would do the same.

The coolant spray on the IC works great for short runs - drag racing or solo events, but hard to carry enough fluid for a half hour road race.  Ditto for NOX.....

BoxheadTim (Forum Supporter)
BoxheadTim (Forum Supporter) MegaDork
1/25/21 1:38 p.m.

In reply to wspohn :

There is an air intake that directs airflow to the IC when the car is moving. ISTR that the fan is basically there for when the car is stationary (to avoid heat soaking the intake air) and when the engine bay gets really hot even when the car is moving,

JG Pasterjak
JG Pasterjak Production/Art Director
1/25/21 2:58 p.m.

In reply to crankwalk (Forum Supporter) :

Don't tempt me...

JG Pasterjak
JG Pasterjak Production/Art Director
1/25/21 3:04 p.m.
BoxheadTim (Forum Supporter) said:

In reply to wspohn :

There is an air intake that directs airflow to the IC when the car is moving. ISTR that the fan is basically there for when the car is stationary (to avoid heat soaking the intake air) and when the engine bay gets really hot even when the car is moving,

Yeah, this.

There are kits that adapt top mounted water to air intercoolers to the engine, but that's additional complexity for minimal gains when I've got lower hanging fruit to pick in the case of this car. The IC is fairly well exposed to the side intake, but even so there's probably batter ways to force air to it than the negative pressure method it uses now. I haven't looked into it much yet, but it wouldn;t surprise me if there were extensions for the intake to grab a little more air. I can't imagine a front mounted intercooler being any more efficient bythe time you actually got the thing mounted and ran decent size pipe all the way to it. You'd end up with 20 feet of tube between the turbo and the intake. 

crankwalk (Forum Supporter)
crankwalk (Forum Supporter) SuperDork
1/25/21 5:25 p.m.
JG Pasterjak said:

In reply to crankwalk (Forum Supporter) :

Don't tempt me...


 

 

 

Ill just leave this here.
 

 

JG Pasterjak
JG Pasterjak Production/Art Director
1/25/21 7:46 p.m.

The true "No Fs given" path is to put the IC in the trunk and run the hot and cold pipes through the rear firewall. Bring fresh air in from the top or bottom and vent it out the back. Not sure I'm ready to lose that much grocery room, though.

fatallightning
fatallightning Reader
1/25/21 8:57 p.m.
crankwalk (Forum Supporter) said:
JG Pasterjak said:

In reply to crankwalk (Forum Supporter) :

Don't tempt me...


 

 

 

Ill just leave this here.
 

 

That side feeds the airbox. Some guys ague that it's actually counterproductive because MR2s flow air from bottom out the top. On true Toms T020 MR2s, I believe the scoop is sealed against the airbox.

crankwalk (Forum Supporter)
crankwalk (Forum Supporter) SuperDork
1/25/21 11:19 p.m.
fatallightning said:
crankwalk (Forum Supporter) said:
JG Pasterjak said:

In reply to crankwalk (Forum Supporter) :

Don't tempt me...


 

 

 

Ill just leave this here.
 

 

That side feeds the airbox. Some guys ague that it's actually counterproductive because MR2s flow air from bottom out the top. On true Toms T020 MR2s, I believe the scoop is sealed against the airbox.

I'm aware that side is the airbox but the point was snorkel.  Here's one on the other side. They are available for both sides.

 

spandak
spandak HalfDork
1/26/21 10:30 a.m.

Not sure it matters if those work or not, they look fantastic

racerdave600
racerdave600 UltraDork
1/26/21 11:00 a.m.

Back in the '90's my MR2 Turbo needed a timing belt change.  My buddy owned a shop and wrote on the ticket:  Needs timing belt, Lift Hood, Replace Car.  I did the next one.  Yeah, replace everything near it.  

Kaliostro
Kaliostro New Reader
2/26/21 8:57 p.m.
spandak said:

Not sure it matters if those work or not, they look fantastic

Yes and you can't argue, but I think they work.

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