High Compression Ratio ----> Detonation

[oldeskewltoy]

apardal Wrote:Knowing this, I installed a thicker head gasket of 0.8mm. 12:1 CR is good because I can reach higher levels of power with bigger cams.

And 12:1 isn't that much of a problem. It just needs more care with ignition , fuel and cam timing.

Best regards

??? Thicker? Thicker than what? Stock head gasket is 1.2mm. Using the TRD .8mm raises the compression.........

[apardal]

I had a TRD 0.5mm before.

[apardal]

I've just measured my cam timing, and it is as HKS recommends. 110º intake and exhaust. I'm going to try and increase cam overlapping to try and reduce the dynamic compression.

Spark plugs of heat range 7 are also ready to assemble. I might have some news tomorrow.

I'm a little surprised that no one has ever used a setup similar to mine, with 12:1 compression ratio :S.

I guess I'll have to install some bigger camshafts and MegaSquirt!

[Uzelac]

Continued ?

[irishtwincam]

Your cam timing is wrong.
Also with high compression and cams it should be recommended to use EMS!

Increased performance, needs headers, more performance with higher compression.
Mfg. recommends setting the cam at

max lift for the intake at 106° ATDC
max lift for the exhaust at 116°BTDC.


Same cam timing applies to the following cams
264°_____7.6mm_____In valve open 26°BTDC_____ex valve open 68°BBDC TRD - no longer available.

264°__7.9mm____Toda - p/n 02.TD.CS4AGCJ2
264°__8.35mm___HKS - p/n 2202-RT032, Can be used on 4AGZE
264°__8.7mm____Toda - p/n 02.TD.CS4AGCJ3, Recommended to use Toda’s valve train kit, i.e., under bucket shims
264°__8.9mm____Toda - p/n 02.TD.CS4AGAI1, Recommended to use Toda’s valve train kit, i.e., under bucket shims

Copied from http://club4ag.com/technical_main.htm


More cam card images here, but Ive been looking at some of the numebrs and they are either wrong or I dont understand maths and engines.
http://s223.photobucket.com/albums/dd186.../CamCards/


That crystal hack aint a great idea as your fuelling and timing events will be out of sync!

[oldeskewltoy]

irishtwincam Wrote:More cam card images here, but Ive been looking at some of the numebrs and they are either wrong or I dont understand maths and engines.
http://s223.photobucket.com/albums/dd186.../CamCards/

Hmmm can you describe what it is you see? Btw... THANK YOU for the english HKS info!!

[jondee86]

Yes... interesting thread

BCPR6EY11... fairly certain these are the OEM "shopping basket" plugs.
I would be running at least one heat range colder.

110-110 also sounds like stock cam timing. I would have expected to
see some different numbers for longer duration cams. So yes, more
overlap might be helpful.

Cheers... jondee86

[irishtwincam]

111/111 is stock timing
some books put it to 110/110.
Much of a muchness.

As for the cam cards, there seems to be greatly differing numbers for basic cams like 256/264/272 between the sheets.

Also, some of them have hand written values that dont correspond to the "paintbrushed" values iin the corners.
One cam cards duration adds up to 288 and its labelled a 264 cam card?

Just take them with some caution.
If you can hunt down TRD numbers for the cam timing Id trust those
But 106/116 seems to be about right.

[totta Crolla]

I see that you are using SAFC, here is an article about it:
http://www.imoc.co.uk/forums/viewtopic.p...c+ignition
I think they suggest using an adjustable fuel pressure regulator so that the SAFC need not go into negative values, thus changing the timing.

[totta Crolla]

"OEM ECU with new HC Crystal, changing rev limit to 8500 rpm"
Any chance you could give some more details on this mod Apardal ?