Toyota 3S-GE Race Cam advice please

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andy97
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Toyota 3S-GE Race Cam advice please

Post by andy97 »

The 2 litre 3S-GE engine in my Toyota Carina race car is coming out for a refresh this winter & I am looking for advice on new race cams please.

The engine is currently in "Super Production" (or Group N+) spec with standard lift, long duration cams, standard size valves and CR. It has Motec engine management and throttle bodies to give 207 Bhp at 7200 rpm. Pistons are JE forged and the rods and crank are lightend and balanced.

As the rules of the series that I run in are free on cam specs etc then I was thinking of replacing the cams with high lift items but am struggling to source any. Kent & Piper only seem to do cams for 1600 MR2 engines. Does anyone have any advice o whereto source high lift race cams for the Toyota 3S-GE from please?
Guy Croft
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Re: Toyota 3S-GE Race Cam advice please

Post by Guy Croft »

What I would do is ask Kent if they will make a pair of nitrided steel billets. They may want the old cams for patterns.

They have many more profiles on stock than they ever publish, ask for their guidance. I expect they will use a Vauxhall or Ford profile.

It takes a while to make them but they do a lot of this and the results are well worth waing for.

GC
andy97
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Re: Toyota 3S-GE Race Cam advice please

Post by andy97 »

Thanks Guy, I have e-mailed them. I have also finally got hold of the Piper Cams catalogue - I couldn't find a website for them but Demon Tweeks kindly sent me a copy. They list fast road & rally cams but no race cams. I have e-mailed them to ask the same question, though.

Thanks again

Andy
andy97
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Re: Toyota 3S-GE Race Cam advice please

Post by andy97 »

Guy, I have spoken to Piper & Kent & the latter seemed the most helpful. They have the old cams & recommend a profile that gives a higher lift (c 11mm) & slightly shorter duration (300). Interestingly they are very happy to recommend the chilled cast version for my application.
Guy Croft
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Re: Toyota 3S-GE Race Cam advice please

Post by Guy Croft »

Good-oh!

G
andy97
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Re: Toyota 3S-GE Race Cam advice please

Post by andy97 »

Well, to update you, the engine build was slightly problematic as we struggled to find valve springs that did not bind up & this took many weeks to sort. Less problematically, the pistons also needed to have the size of the valve pockets very slightly increased.

Whilst all this was going on other work was being undertaken on the car. The car eventually went to the rolling road this week to be remapped but the results were disappointing - the engine was difficult to set up & has a very lumpy power curve. It is also 2 Bhp less than previously on the same rolling road!

The RR operators diagnosis is that the the exhaust manifold is no longer optimised for the cams & is not allowing all the exhaust gases to escape before the next injection of fuel/air. His suggestion is that we get a standard exhaust manifold (the one on the car is bespoke to Super Production regs) & see what effect that has & then we will at least have an indication of which way to go with a bespoke manifold design.

Now, I'm not at all technical (sorry, Guy) & the work has been carried out by others but I trust the RR operator (he has an excellent reputation & comes highly recommended in the race world) but designing optimised exhaust manifolds seems to me to be a very specialist (& expensive) job. I don't even know where to go.

It just goes to show that changing one component does not necessarily lead to the improvements one expects and that a whole system approach has to be taken. I am learning that the hard way!
Guy Croft
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Re: Toyota 3S-GE Race Cam advice please

Post by Guy Croft »

I'd want a good photoset of the ex header to comment on this.

G
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Re: Toyota 3S-GE Race Cam advice please

Post by WhizzMan »

Do you have data you want to share regarding the cam timing and lift? Did you experiment with the amount of overlap/lobe separation?
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andy97
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Re: Toyota 3S-GE Race Cam advice please

Post by andy97 »

Hi Guy, I didn't really expect an analysis based on my limited information, above. It was more case of highlighting the fact that I discovered that changing one thing inevitably leads to a mis-match elsewhere and I hadn't really considered that. It was a warning to others that the engine should be treated as whole system & not just a collection of parts,whch can be changed independently.

I am not in the slightest bit technical, & don't do my own work unfortunately, so I don't have photos or technical details but I will try & get hold of further info. I am sure that you will think that mine is a naive approach, & I'd accept that criticism, but for budgetary reasons I have to rely on favours or help from others & that means that it's not always easy to get results if you don't always understand yourself the possible consequences of certain advice or actions.
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