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Author: Subject: intercooler advice
subevo

posted on 14/7/11 at 11:14 PM Reply With Quote
intercooler advice

just fitted a rotrex supercharger to my st170 kit car.the inlet temp is around 90 degrees.do i need an intercooler at this temp.theres not much room to fit one if i do.its making 200 at the wheels at 0.6bar.
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CNHSS1

posted on 14/7/11 at 11:26 PM Reply With Quote
yes, imho you do. if space is tight, try a charge cooler (water to air cooler) as the unit is much smaller and has a remote rad and pump for the water in the cooling jacket.





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Strontium Dog

posted on 14/7/11 at 11:39 PM Reply With Quote
Hell yes! That's way to high a charge temp. You want to see half that IMO.

Edited to say I have a good water to air chargecooler I would sell if you choose to go that route!

[Edited on 14/7/11 by Strontium Dog]





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Bare

posted on 15/7/11 at 02:59 AM Reply With Quote
Some trick .. that making 200 hp at 8/9 psi. Did you start with 175 ?
It takes 12 psi for a lowly VW Audi 2.0T engine to make 180/200 hp.
No your charge temps are Not too high, fairly typical actually as you are not compressing the air all that much ay 0.6 bar :-). Certainly lower would be 'better'... but they are not silly high and 'Good Luck' cutting those temps in half :-) Air water gizmos are only 'easy to fit' but not serious kit.. as these heat soak in moments which renders them ineffective.

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sorens2

posted on 15/7/11 at 05:53 AM Reply With Quote
quote:
Originally posted by Bare
Some trick .. that making 200 hp at 8/9 psi. Did you start with 175 ?
It takes 12 psi for a lowly VW Audi 2.0T engine to make 180/200 hp.
No your charge temps are Not too high, fairly typical actually as you are not compressing the air all that much ay 0.6 bar :-). Certainly lower would be 'better'... but they are not silly high and 'Good Luck' cutting those temps in half :-) Air water gizmos are only 'easy to fit' but not serious kit.. as these heat soak in moments which renders them ineffective.


You need to rethink your engineering about tuning.

My old Audi S2 with 500 bhp had a charge temp that was about 5-7 deg higher that outside temp.
My VR6 supercharged made 270 bhp and had the same intake temp as the Audi.

Offcourse when you compress air the temp rises but you must bring it down again, specially on a high compression engine as the ST170.

I have seen many air/water chargecoolers that work very well. Often better that air/air as they circulate the water and has a fan that constantly cools it.




Soren S2

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flak monkey

posted on 15/7/11 at 05:54 AM Reply With Quote
Are you talking deg F or deg C?

If C then yes they are way too high. Normally you should see inlet temps below 40deg C if the intercooler is working well and you arent running silly boost levels.

Ignore what Bare says, he still hasn't a clue but loves to comment on threads about supercharging/turbocharging.

I would wager that if you could get the inlet temps down you could see another 10bhp on your figures. 8psi should see a 30% (or so) gain over the standard engine output.

On a standard cams my Duratec (150bhp in standard form) and running 11psi (0.75psi) it made 230bhp at the wheels (about 250bhp at the fly) - thats a 66% increase in power over stock at 0.75bar. And made 291bhp (at the fly) and 240lbft at 0.67bar with mild road cams without changing anything else. I also have the dyno print outs to prove it.

Here is my intercooler setup

Rad fitting 2
Rad fitting 2






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sorens2

posted on 15/7/11 at 05:58 AM Reply With Quote
This Gallardo makes 1000 bhp with air/water coolers.


Soren S2

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sorens2

posted on 15/7/11 at 06:01 AM Reply With Quote
My 174 bhp VR6 was only boosted 0.35 bar and made 270 bhp.

So your 200 bhp is very poor indeed.

Soren S2

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tomgregory2000

posted on 15/7/11 at 06:26 AM Reply With Quote
quote:
Originally posted by sorens2
My 174 bhp VR6 was only boosted 0.35 bar and made 270 bhp.

So your 200 bhp is very poor indeed.

Soren S2


Im sorry but you cant really make comments like that as we dont know what size supercharger the op has fitted as a small supercharger running at 0.6 bar will be pushing less air than a large charger running at the same 0.6, so you cant jump to conclusions as we dont have all the information.

But yes you should look at fitting an intercooler, it may mean moving/changing the rad to make space

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deezee

posted on 15/7/11 at 07:11 AM Reply With Quote
quote:
Originally posted by Bare
Air water gizmos are only 'easy to fit' but not serious kit.. as these heat soak in moments which renders them ineffective.


What a load of crap. If a charge cooler is suitable for a Celica GT4 running 260bhp on its 2.0l turbo charged engine, then its pretty effective.






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sorens2

posted on 15/7/11 at 07:13 AM Reply With Quote
Thats true Tom.
But superchargers are usually quite effective.
Mine was a bit large.



Soren S2

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matt_gsxr

posted on 15/7/11 at 09:02 AM Reply With Quote
I looked into which front mounted intercooler would fit.

List of possibles:

RX7 FMIC
Nissan Pulsar GTIR with inlets/outlets moved
Audi (they run 2 one in each front of each front wheel)


Quite a useful link here: http://autospeed.com/cms/title_The-Worlds-Biggest-Intercooler-Comparison-Part-Two/A_1946/article.html

The general problem is that they are all wide and the 7 front isn't.

Charge cooler is the other option, which is good for packaging, but you need a pump, radiator, heat exchanger which gets a bit more complicated and expensive. I didn't want to go that route.




In the end it turns out that on a Phoenix you can go wider because of the bonnet and I got a more conventional one. Inlet temps dropped from 60degC to ambient +5degC.

Matt

p.s. From what I have read 90degF is fine but 90degC isn't so clever

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MikeRJ

posted on 15/7/11 at 03:52 PM Reply With Quote
quote:
Originally posted by sorens2
My 174 bhp VR6 was only boosted 0.35 bar and made 270 bhp.

So your 200 bhp is very poor indeed.

Soren S2


At 0.35 bar (5 PSI), assuming no temperature change in the inlet charge and ignoring any restrictions in the induction path, you would be pushing 33% more air into your engine (and the extra fuel of course), yet you increased it's output power by 55%?

How do you explain this magical feat?

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sorens2

posted on 15/7/11 at 04:46 PM Reply With Quote
Im also impressed with the numbers but more impressed with the way it drives.
It just feels like a 5.0 L engine now.
I guess I just hit the right setup here.

Soren S2

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subevo

posted on 15/7/11 at 06:05 PM Reply With Quote
thanks for all the replies.

without the supercharger hose connected to the inlet it gave 130hp at the wheels. roughly say 150bhp at the flywheel.which is what we thought.as st170s dont often achieve the 170mark.

the supercharger is the smallest in the range. sp64 i think.

it achieved 197bhp but on the final run at each stage was 8bhp higher until near the top end when all of a sudden the power would drop about 30bhp .

the tuner was concerned about this.done a few checks and only conclusion was either air temp too high or something inside standard plastic plenum chamber was causing it.he wasnt convinced it was air temp though.

anyway back to the intercooler.the water/air barrel shaped one looks like what i need.as my engine is mounted at the rear.

next week i will be trying it out at curborough sprint track.so need to wait til then.before seeing if its a success.

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scutter

posted on 15/7/11 at 06:18 PM Reply With Quote
Mr Subevo, I/we need pics! My st170 lump makes 151 at the rear wheels (the 1 is important ) boosted engine sounds like a good way to go.

ATB Dan.





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subevo

posted on 15/7/11 at 09:33 PM Reply With Quote
ok pics coming soon.
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nasty

posted on 16/7/11 at 03:18 AM Reply With Quote
I'm not an expert on turbocharging or anything, but if you're looking for a small cheap intercooler, you might want to check out the Mr2 one. It's probably not going to be the best (by any stretch of the imagination), but they are cheap and suitable for mounting on top of the engine or in the nose of a 7-a-like. It's a comparatively cheap solution.
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MikeRJ

posted on 16/7/11 at 11:23 AM Reply With Quote
quote:
Originally posted by nasty
I'm not an expert on turbocharging or anything, but if you're looking for a small cheap intercooler, you might want to check out the Mr2 one. It's probably not going to be the best (by any stretch of the imagination), but they are cheap and suitable for mounting on top of the engine or in the nose of a 7-a-like. It's a comparatively cheap solution.


Plenty of the more enthusiastic owners replace them with uprated ones as well, so standard parts should be fairly easily available.

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subevo

posted on 5/8/11 at 08:10 PM Reply With Quote


















[Edited on 5/8/11 by subevo]

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posted on 5/8/11 at 08:47 PM Reply With Quote
IMHO, I agree with most of the above, I am using the PWR set up above and it works really well. Your intakes, if degrees C, are way to high. IIRC you can lose upto 1 hp per degrees C of intake temp. The power drop off could have been your ecu retarding the ignition for safety reasons. The stock RX7 ECU retards the ignition at 60 degress C. With your set up i would say the PWR set up is a bit overkill. A celica one would be fine if you are on a budget or you could make up a kit from ebay bits.

In an ideal world an intercooler is the easiest and best option providing you can get a decent air flow through and it flows enough boost without restricting too much. Not so easy on a kit car and I couldnt and it was compromising my oil temps too much so i went with the charge cooler option and it works really well.





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ss1turbo

posted on 5/8/11 at 10:15 PM Reply With Quote
The air/air vs air/water/air debate will run and run...but installation does always play a major part. Both setups can provide similar results and the intercooler route is normally cheaper but you must have that access to a large amount of cool air at all times. Its a lot easier to route a couple of 19mm water hoses than some 60mm air hoses around a cramped engine bay/bodywork! Don't forget that in a turbo installation (not quite so applicable here, I know), it does increase lag if you start to add long pipe runs to the intercooler and back.

I personally tend towards chargecoolers and there are some good value off the shelf versions available (see above) as well as the Pace modular cube version. OE ones are fewer - Celica (mentioned), Subaru (mine - looks very similar to the Celica one), Focus RS can all be adapted to other installations quite easily but the barrel versions need nothing much more than the space of a straight run of pipe to fit into. Pumps are easier to come by these days (auxiliary heaters, normally) and for a secondary rad, pick anything that fits the space you do have (be it a bike or even small car radiator).

Those charge temps are to my mind too high; the cooler the better IMHO.





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posted on 5/8/11 at 10:59 PM Reply With Quote
i am using a davis craig pump and a mocal oil cooler for the water cooling and the temps arnt much different to the intercooler i had fitted.

I found the PWR quite difficult to fit due to its shape, where as something like this would be much easier to fit and im sure just as good. I went for the PWR because i know it can flow at least 600 bhp on an RX7 as some of 9 second drag rx7's used to use them.

LARGE LIQUID WATER AIR TURBO CHARGE COOLER 220x250x115 | eBay





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