Hi all

Ive had half a dozen Hondas (civics, crx and rsx all modded) so my eyes opened wide when I came across a particular ITR for sale.

I noticed it had been worked, Jun 3 racing cam, forged pistons, hks coilovers, HKS headers, Apexi exhaust, etc. After a <quick> drive I was sold. 45,000kms on it.

But driving this thing daily, I quickly realised that even on premium I was getting some pinging... oh no. The horror of detonation visualisations sets in.

So wheel it into the workshop, and after a comp test its running 14:1. It really needs racing fuel... it had been completely detuned (really rich) such that it would even work on 98 premium. As I found when I run 98 premium (BP Ultimate 98 is the best we have on the road in Australia) and octane boost it runs much better.

But this now leads me with a dilemma.... really it seems that in order to enjoy this ride on the road, Im going to have to change the pistons and rings and drop its compression... say to 12:1 ??? I also noticed that they already swapped the head gasket to lower compression slightly, so thats not an option.

Any ideas on what to do here?

While redoing the bottom, should I do anything else? Head seems OK. Heres a dumb question - if I decompressed it can I go a turbo kit, even though its got the jun cam, or will that have to go too ? JR supercharger?

The headers had a major dent, and started opening up, so ive changed the exhaust for an Xforce system... seems good.

The thing is a rocket even detuned, FWIW... the guys who did the mods for this rich student that had it, tell me it was pulling high 13s at its peak... but who knows.

After finding how much teh B18C7 costs s/h, Im worried that if I hammer the beast any more without decompressing, Im going to do some serious damage... Im all ears here. Any other issues?

Running race fuel all the time will become too expensive for traffic light encounters

cheers,
Devster

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by devster &raquo;</TD></TR><TR><TD CLASS="quote">I also noticed that they already swapped the head gasket to lower compression slightly, so thats not an option.</TD></TR></TABLE>

You can get a really thick headgasket. It is an option.

 

Run a restrictor plate.

On a serious note, has anyone increased the combustion chamber volume via machining on a PR3 head? What were you compression numbers? Have you tried colder plugs? What is your timing? Is your knock sensor functional?

 

Does it ping more on teh LO or HI cam?

Try retarding the intake cam to help bleed off some of the cylinder pressure. Just be careful that you don't run out of clicking clearance.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris F &raquo;</TD></TR><TR><TD CLASS="quote">You can get a really thick headgasket. It is an option.
</TD></TR></TABLE>

This might be worthwhile, in that these gaskes normally lower the compression ratio of a USDM ITR motor from 10.6 to 9:1.

Cometic
http://www.tunerschoice.com/xq...t.htm

Inline Pro (go to engine components, headgaskets, then 89-00 B series 3.0 mm).
http://www.inlinepro.com/

 

for the lazy looking at the inline pro

http://www.inlinepro.com/catal...40_65

 

What formula did u use to determine 14:1 comp ratio?

 

I forgot to mention - it is drinking some oil, about a litre every few weeks. [I did about 1000kms] This could be a related sign of impending doom and factor towards stripping it down. Its not dripping or blowing smoke.

Formula? Youve got me... I assume in the workshop they used a compression tester. Thats the figure they gave me. Im using Speedworks (in WA Australia)

It pings on the hi cam, mainly under high gear / torque. If I baby it, no problem.

Could be worn and need some bottom end TLC?

If an inspection shows its OK, might try the head gasket option.

Thanks guys.

 

Try retarding the intake cam a degree and then two to see if you can get it to stop.

I also recommend remapping the ignition timing basemap. Between remapping the ECU and tuning the cam gear, you should be able to reach a compromise of power and reliability while still using just pump gas.