Rb25 Exhaust Cam - Retune Required?

[MANWHOR3]

gday fellars.

Ash, before you say search, I have.

Atm, I've bascially done all the usual mods e.g. exhaust, cooler, air filter, fuel pump etc. I'm looking at getting it tuned, coz it's running liek crap with stock ecu.

I will get an exhaust cam gear at some stage (thinking about it when 100000ks comes, and I have to do the timing belt).

If I install the cam gear later and dial it into the correct setting, will I have to get it retuned. i.e. should I just get the cam gear now before tune?

Cheers

Edited December 17, 2005 by MANWHOR3

[paulr33]

you wont need to get it retuned. you can't tune the stock ecu and a remap of it will cost you about $1500 ish if you get it done with a chipswap on your stock ecu board. or you can get someone to remap another r33 ecu and swap it for yours for around $500 ish. exhaust cam wont give you any power, the stock one is fine.

define running like "crap"

what are the problems you are seeing/feeling ?

[MANWHOR3]

remap = $300 by our forumn member toshi.

Sorry about the confusion, what I meant was exhaust cam gear. These are known to give improvements.

Paul, I'm not new to skylines, and i'm not asking the usual question, oh, my car has more boost, it runs like shit what is it. I've read almost everything everyone has said about it on SAU and I know that it's the stock ecu running it like shit. I ran it on the dyno, and AFR were down to between 9 and 10.

What I am asking is not about whether getting an exhaust cam gear will give performance improvements or whether a tune is good. I am getting it remapped regardless. I just want to know whether I need to get it retuned after exhaust cam gear install.

I imagine it would need to be tuned, since the cam gear will change airflow.

Edited December 17, 2005 by MANWHOR3

[BHDave]

To optimise it, yes a retune will be required. At the least a dyno run after messing with the position to make sure your mixtures are ok.

[paulr33]

no performance increase from exhaust cam gear

[rob82]

Not sure about other peoples experiences but I havn't seen enough gain to warrant retarding the exhaust cam to bring boost on eariler. The problem then becomes you start to heat the exhaust valves higher up in the rev range which introduces the chances of detotnation (and it will ping).

[R31Nismoid]

I just want to know whether I need to get it retuned after exhaust cam gear install.

now your question is clear, answer is simply.

yes.

although i agree with pauls post above, seen a number of rb25's now with cam gear/no gain

[Bullant47]

I've read a lot of threads on this forum stating "No gains made with Variable Exhaust Cam Gears on GTS-t's," but when I got ours tuned at C&V it made around 7kw@tw more. Con at C&V thought realisticaly it was more because the engine was becoming heat soaked. John Penlington at Unique has dyno sheets showing a larger improvement than mine tuning Variable Cam Timing Gears on a GTS-t. I'll ring John and ask him to post his sheets.