Intercooler recommendations

MatBat · Post by **MatBat** » Sun Jun 03, 2007 8:40 pm

I've got the turbo kit fitted but need to sort some form of intake plumbing as I want to run high boost eventually, so I'm going to install an intercooler from the start. Does anyone have any recommendations on what fits best and has reasonable efficiency?

Post by **jif** » Mon Jun 04, 2007 12:52 am

no recommendation per se, but I've found Corky's site useful (since he wrote the book!) ...

http://www.bellintercoolers.com/pages/aachart200.html - gives size vs flow

http://www.bellengineering.net/Pages/comments.html

Anthug · Post by **Anthug** » Mon Jun 04, 2007 9:58 am

Hi,

I fitted a an INTERCOOLER RACEPRO 500x230x76mm from Trademe and it fits perfectly. Only downside was the 3" inlet/outlet but if you can find one with 2.5" inlet/outlet you don't have to use reducers.

Anthony.

Post by **jif** » Mon Jun 04, 2007 5:26 pm

just out of curiousity, I ran the numbers for an OEM ("way too small") FD rx7 intercooler:

core dimensions - 2.5"d x 12"w x 5"h
rating for similar sized 150 in^3 BEGI core - ~570 CFM (cubic ft/min)
rated power - 570 CFM / 160 = 358hp (crank)

Interestingly, the CFM rating actually *drops* (bad) as tube length increases... and the CFM increases with the # of tubes...
2.25 x 5 x 12.1" = 530 CFM
2.25 x 12 x 12.1" = 524 CFM (longer tubes)

So maybe Mazda did know what they were doing

- their "way too small" IC has 22 short tubes, compared to the more typical 15-17 ...

/blather

SLYDIT · Post by **SLYDIT** » Mon Jun 04, 2007 8:01 pm

i'm running an intercooler from a 3 liter isuzu diesel! similar size to an rx7 one but thicker, its certainly not creating any undue restriction.
On our little 1600's you dont need a HUUUUGE intercooler... i reckon those cheapy ones from repco similar size to a mitsi evo one would do the trick with the 2.5" inlet/outlets. Using 2" pipes from the turbo to the I/C and 2.5" from the I/C to the throttle body will help getting it all in there.
EDIT: similar to a series 4/5 rx7 I/c not a batman which has a very small core frontal area.

MatBat · Post by **MatBat** » Mon Jun 04, 2007 9:43 pm

I was considering a "batman" RX7 intercooler. It looks really small but would it be sufficient?

Post by **jif** » Mon Jun 04, 2007 11:26 pm

looks ok until you head north of 300hp (batman= FD rx7, so we're talking about the same thing) ...

Miatamad · Post by **Miatamad** » Tue Jun 05, 2007 7:52 am

I have a Bell Engineering Intercooler from Corky Bell who is one of the
main turbo suppliers in the US (there are Bell / Begi and Flyin Miata).

My intercooler is not that much larger than the RX7 unit and is fine for
12PSI (yeah, yeah I know its not measured by PSI - but I wanted to
indicate that NZ's not so hot that you cannot run on a fairly small
intercooler (as long as its good quality)

C

SLYDIT · Post by **SLYDIT** » Tue Jun 05, 2007 10:23 am

you dont want to go too small either as they maybe ok in terms of flow, but they will heat soak quickly negating the benefit of an I/C.heatsoak is going to be more of a factor for I/c selection than actual flow limits.
A really good book is "21st century performance" by Julian Edgar..explains I/C selection really well and talks about water sprayers for small I/C's.

MatBat · Post by **MatBat** » Tue Jun 05, 2007 10:57 am

I was going to mount it infront of the radiator so heatsoak shouldn't be too much of an issue. I've got quite low underbonnet temps anyway due to vents in the bonnet. I'm thinking I'll go with the RX7 intercooler for starters (it's only $15) and I can upgrade if and when I need to.

Miatamad · Post by **Miatamad** » Tue Jun 05, 2007 10:09 pm

I popped down to the garage to take a couple of pics so you guys can see the size of the unit I have installed. Its not too large and allows plenty of flow to the rad.

Hope that this helps (sorry if this double post to email - I had to edit the original posting due to posting the same pic twice)

MatBat · Post by **MatBat** » Tue Jun 05, 2007 10:41 pm

Cheers for that, doing a bit of research the RX7 intercooler (bought it now) should be okay for the 12PSI I hope to run.
I might run water/methanol injection too if I need to keep the intake temps down lower.

Currently I'm having a fun time trying to figure out the wiring on my additional injector controller, grr.

Any ideas on what 12PSI of boost on a 1.6 with low restriction exhaust should roughly produce in rwhp?

Post by **jif** » Wed Jun 06, 2007 8:11 am

generally it'll be:
new hp = orig hp * ( (new absolute psi) / (absolute atmospheric psi) )

sooo... very roughly ... 116 * ( (14+12) /14) = 214 crank hp ?

This ignores tuning, turbine backpressure etc of course, but it's a decent guesstimate.

SLYDIT · Post by **SLYDIT** » Wed Jun 06, 2007 10:29 am

yeah 215RWHP is about right but as jif says thats with optimal exhaust and tuning...which you dont have with an extra injector controller and (no?) timing control which means youll have to tune safe... i with that setup id be looking at around 190WHP.

My setup makes good Hp figures for the boost pressure because i have a turbo that flows better, a manifold and dump pipe combo which lets the air out of the turbine well.....Oh yeah and 2 hours of dyno time on 98 octane gas.

MatBat · Post by **MatBat** » Wed Jun 06, 2007 5:53 pm

My engine has already been quite worked so was probably pushing a fair bit more than 116hp. I've got a superb flowing exhaust and I've decided the extra injector is a waste of time so I'll go down the bigger injectors and link route (unless anyone can recommend an alternative) basically I want a nice round 200bhp at the wheels.