Toyota Twin Cam

Road-race engines and ancillaries - general discussion
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racehead
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Joined: March 18th, 2008, 1:01 am

Toyota Twin Cam

Post by racehead » May 3rd, 2011, 12:41 am

This a Toyota Celica GTI 2000cc Year 1990. The engine is a 3 SGE. A friend of mine wants me to port this head. We went for a ride, I was dissapoint.... this has a bad bottom end torque and it only picks up at 5000RPM. After I took a look at the induction system was surprised again of the diameter of the intake runners, they are very big the the velocity propably very low. That is one of the reasons he complains that he wants more low end torque. Does any people from this forum has any experience of these engines or is a fan. In my opinion these heads don´t need to be ported. Any opinion is very welcome.
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WhizzMan
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Joined: August 13th, 2010, 9:05 pm
Location: Amsterdam, the Netherlands

Re: Toyota Twin Cam

Post by WhizzMan » May 3rd, 2011, 8:02 am

From what I gather, the heads can do with a proper valve job, but no large chunks of metal need to be removed. The intake uses a system called ACIS, which has "throttle valves" controlling the intake runner length. If that system is maladjusted, broken, or not re-adjusted after tuning, it will most likely mess up intake air speed. I'd focus on getting the ACIS to function properly, if low rev power is the key target.
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racehead
Posts: 5
Joined: March 18th, 2008, 1:01 am

Re: Toyota Twin Cam

Post by racehead » May 9th, 2011, 12:15 am

There was a menber from this forum that had a Toyota MR2 as I remember it was red. I have done some reserch but could not find it. The reason is that the this Celica GTI share the same engine as the MR2. This car looked very good and had some modifications.

WhizzMan
Posts: 459
Joined: August 13th, 2010, 9:05 pm
Location: Amsterdam, the Netherlands

Re: Toyota Twin Cam

Post by WhizzMan » May 11th, 2011, 11:20 pm

This engine is the second phase version. The same was indeed also used in the MR-2. I've found some useful info for it on MR-2 sites already.
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racehead
Posts: 5
Joined: March 18th, 2008, 1:01 am

Re: Toyota Twin Cam

Post by racehead » May 13th, 2011, 8:52 pm

Yes, you are right Whizz Man, this engine is the second generation.
The compression ratio is 10:1
intake valve 33.5 mm
exhaust valve 29 mm
intake & exhaust lift 7.65 mm
Bore & stroke 86mmx86mm

Could you be so kind to share the information that you got?

WhizzMan
Posts: 459
Joined: August 13th, 2010, 9:05 pm
Location: Amsterdam, the Netherlands

Re: Toyota Twin Cam

Post by WhizzMan » May 15th, 2011, 11:29 am

I've found an article here:

http://www.roadandtrack.net.au/index.ph ... a&Itemid=4

Summary: it's a good engine, you need to do valve angle jobs and change cams+compression to get significant performance gains. Most of the stock parts are pretty much dead on the money for road usage.

Most other serious things I found offer the same information. There is plenty to be found about specific cone and panel filters, 4-1 exhaust systems that will give you a few BHP extra, but in general, the original 2nd gen engine should behave just fine, also in lower revs. All mods that have serious power require either a turbo or lumpy cams and high revs.

If the one you are working on doesn't have power in lower revs, I suspect there's something wrong with it. Cam timing off, ECU programming not correct, broken sensors, bad spark, that sort of things.
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