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 Post subject: alloy radiators
PostPosted: Sat Oct 26, 2013 11:26 am 
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Some useful research.

http://www.celica-club.co.uk/forum/inde ... -rdiators/

tctech wrote:
Posted Yesterday, 07:08 PM
After extensive testing today with the stock rad vs alloy rad it would appear that the alloy rad is less efficient than the stock item
Both can maintain reasonable temps on idle and under partial load ,however the difference is clear on boost between the two .
The alloy rad fails to deliver and is restrictive in flow characteristics ,in such that it pressurises the cooling system and expands the coolant hoses after short runs and then struggles to cool the system .
The stock rad however can manage the increased flow and temperatures and does not pressurise the system ,looking at the design of the two it is apparent that the inlet for the top hose in the alloy rad is into too small a chamber and the header tank is nowhere near big enough to cope with the increased flow from the water pump and thus restrictive

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 Post subject: Re: alloy radiators
PostPosted: Sat Oct 26, 2013 2:52 pm 
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Location: cornwall
Car Model: ST185 CS/RC
is this for all alloy rads or cheapo ones i have alloy rad and dont seem to have any probs my hose connections same size as stock im not running mega boost but run 1.1 bar and is driven enthusiastically


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 Post subject: Re: alloy radiators
PostPosted: Sat Oct 26, 2013 3:16 pm 
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Interesting read. It's a bit presumptive to say that blanket one type is better than another.

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 Post subject: Re: alloy radiators
PostPosted: Sat Oct 26, 2013 6:18 pm 
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Tend to agree with Mike. I'm not sure how informative the Celica Club thread is. I've looked at the whole discussion and there's no mention of what make the alloy rad is. The guy posting the results included this pic Image
The angle of the photo might be deceptive but the header tank looks tiny by comparison with the Koyo alloy rad so its no wonder he is experiencing cooling issues. A contributory factor may be a restrictive core design. Different cores all have different heat rejection characteristics. Theoretically you could calculate what type of core you need for a given power output and coolant flow but I'm not that clever!

Having had the rads made up for my track toy project by Bob Hall at Concept Racing I have learnt a lot more about rads and would probably get him to make up a rad with the right core for the job. He does a lot of work for historic Group B rally car restorations as well as everything up to F1 so he knows his stuff. It's critical to get the correct core spec and I'm sure a lot of the alloy radiators offered for sale use cheap and inefficient cores. This may even be true of the Koyo. I've seen two different types of core used on the Koyo both of which were made in Indonesia. I haven't heard of any problems with any type of Koyo rad but I guess if you push the engine power up then even they may struggle.

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 1:05 am 
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I would suspect it was a cheap eBay one.

he did point out that the new Toyota rad is also alloy, just better designed.

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 9:30 am 
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I will admit we have done testing on these alloy rads compaired to the stock toyota rads, both varients the twin core copper and the alloy one. Top of the list came the twin core copper followed by the toyota alloy one. I would not reccomend the after market alloy ones for track use at all.

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 12:32 pm 
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When you say 'these alloys rads' which ones are you referring to? The ones in the thread or just in general?

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 12:35 pm 
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We tested with a koyo rad, and a copy

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 12:37 pm 
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That's interesting, I use a koyo on my car, never had any issues and done many trackdays. But then I am not running a massive amount of power.

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 5:21 pm 
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I have tested both as you see on the ccuk forum, and think it all so is down how much power and how hard you are pushing the car, if you read threw my test results the 56mm ally rad I have was rely bad and did not cool very well, was fine for a stock ish set up but any thing more than that then the stock rads is 1 of the best set ups you can have, just need to make shore the stock rad is in good condition, the best set up for cooling is to have side tanks instead of the top header as this cooler more efficiently, 1 of the best mod you can do to the gt4 is to fit a header tank, it all so add's about good 1/2litter more coolant and any air is in the tank in stead of thin the rad or block, this was my 56mm ally rad

Image
Image

its now gone for scrap as it was so bad at cooling and im back on a stock rad,

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 7:14 pm 
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I'm starting to think this may be the issue on my 185 that I'd put down to HG or cracked block. Thinking back, I changed away from my old alloy rad when i fitted the new engine as it was corroded and leaking while the car was stood. Looking closely and taking into account metal thickness, there can't be more than 5mm gap for the water to flow - quite likely causing cavitation in the pump.

My original was one Nigel organised in a group buy years ago and was much better designed iirc.

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 8:06 pm 
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Nigels gb was with Golpher iirc , I had one fitted to the rc running 1.1 bar knocking out nearly 260 bhp and never ever had an issue with temperature or cooling :) . It did seem well made , and at the time around £220 .

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 8:27 pm 
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But the thing is why are people going for the biger ally rads if the first place. I mush add mit i did it my self as i thought my heating problem was the rad but in was a leaking head in the end. The stock rad is good for 500+bhp its seems to me most just fit the biger ally rads cos others have done it so it must be right. But its not. And 260bhp is nothing thats what a stock st205 ane caldina run all day long on a stock rad.

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 8:47 pm 
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Lou, the stock rad alone won't survive 500bhp, mine couldn't cope with 300-330bhp on track BUT with a header tank fitted AND a swirl pot then it may be OK. IIRC Adrian had a stock rad fitted on his Gen 7 Celica GT4X which was knocking out ~700bhp but he had all the other mods to the cooling system. I'm pretty sure that's why the stock rad survived. He was also running Evans coolant and unpressurised for a spell :shock: !!!!

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 Post subject: Re: alloy radiators
PostPosted: Sun Oct 27, 2013 9:18 pm 
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there are plenty of gt4 out there running out there with 400+bhp on a stock rad , the problem starts when people tune the engine and for get the rad is 20+years old so no wonder its is going to fail, nothing to do with the rad carnt cope, all I have on mine for cooling is a stock rad and header tank, on the road my remps don't go over 85c, and if you have seen me on track I drive flat out all the time at 1.5bar for 20mins and my temps stay at just over 95c and that's on a stock rad, the st205 and caldina run 250bhp on stock rad all day long from stock,

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