New Owner Needs Some Modding Advice!

[Chillipower]

Hi, I recently got an RZ-S j-spec and am loving it!!! :D

The car already has some tuning parts on it (and was allegedly tuned in Japan). It goes very well but I have little to compare it with, except for my previous 280bhp car, and its a lot quicker than that.

It boosts at .8bar from low revs rising to 1bar at 3500 and holding to the red line. Is this standard boost?

Its got a (Veilside I believe) induction kit (with a heat shield) and large cat back exhaust. It was rumoured that it had a rare jap ecu chip in it, that could be nonsense - I havent checked yet. The car is early 96 (Feb) so that makes it an ODBC-II car I believe.

So my question is, being already at 1 bar, with j-spec ceramic turbos (I assume they are stock, will check) is it still worth me doing a double de-cat downpipe mod?

I understand that I will need a restrictor ring, so is new de-cat downpipe + restrictor better than the cat set up I have? I seem to read varying information but people suggest that up to 1.1 to 1.2 bar is safe on the ceramic turbo set up, I am wondering if the restrictor ring will accurately give me this (since its so close anyway) or if I will need an additional electronic boost controller (e.g. the Apexi AVC-R). With this correctly set up it seems (from reading) this might buy me an extra 40-50bhp?

If the downpipes are worth it, then anyone care to recomment a make/supplier and even a fitter for the south east (Preferably Sussex but can travel of course).

so any advice would be much appreciated, I am very happy with its performance for the moment, I am just finding out what I can do. I love the virtually lag-less j=spec turbo set up, however in the future - who knows, it might get a big turbo replacement (if I can save up the pennies),

so any advice much appreciated,

thanks,

Louis

PS: Fab cars!!!

[Martin F]

Its got a (Veilside I believe) induction kit (with a heat shield)

It won't be a veilside one as AFAIK they don't do one.

Stock boost is 0.8bar.

[Chillipower]

Ok well I appologise if that part is incorrectly identified, I will try and find out exactly what it is then, I guess its not important regarding the post,

By the way though, Veilside do make induction stuff such as inlet manifolds and the like, I can't comment on them making an induction kit (or the one I have fitted) so I will bow to your greater knowledge on that,

.8 bar boost standard, well I am getting about 1bar, thing is i get .8 bar right from the get go (low rpm, around 1800-2000) - is that normal also?

I'm just trying to work out whats been done to the car and from that what I might do next, as I said the car is really quick as it is so I am in no hurry to change things without careful consideration,

cheers,

Louis

[Leeky]

You still got the cats in?

It shouldnt be boosting it 1bar with the cats in, so there must be a controller of some sort raising the boost somewhere.

If there is not an electronic one i sight i assume it has a bleed valve on the turbo pipe somewhere

Bring it to JAE so we can see it and then we can answer all your questions

[Chillipower]

Yes it still has the cats, it recently went through the e-sva with them,

Apparently the chap I brought it off said it was running a modified ecu chip (and was tuned by "top secret"), I have yet to confirm that,

I don’t believe its running any sort of bleed valve, the boost is rock steady, no spikes or fluctuations, always .8 then 1 bar - again I will double check for any valves/controllers,

I have nothing much to compare it against, but my friend who has been in one before (a 3.0 TT) came out in it and said mine in "much more urgent" suggesting that if there is a noticeable difference then it must be kicking our a few more bhp than standard. However the one he went in was auto, don't suppose that should make such a noticeable difference should it?

I'd love to come to JAE but since I am such a newbie I haven’t really had time to sort it out. I take it that JAE is annual, but are there any other good meets/events in-between during the year?

I will definitely make an effort to attend events in the future - just probably not this up coming JAE unfortunately.

I notice that up the road in Bolney (Sussex) they have a Jap car gathering, there was one a month or two ago, that also looks like a good thing to go to, although its on the small scale compared to JAE I'm sure,

anyway thanks for the help,

Louis

[Martin F]

Apparently the chap I brought it off said it was running a modified ecu chip (and was tuned by "top secret"), I have yet to confirm that,

If you take the ECU cover off in passengers footwell you can see the ECU. Most of the big Jap companies put their sticker on the outside if they have fettled the ECU.

It's very hard for us to try and help with what your car may or may not have without actually seeing it. There are so many weird and wonderful things the !Removed! do.

Boosting to 0.8bar on the first turbo then going a little further to 1bar is normal for a car where the boost has been increased.

With both CATs in still i'd say somebody must have increased the boost somehow. However 0.2bar could be down to an inaccurate gauge as well.

[Chillipower]

Hi again,

ok thanks for the advice, I'll be doing some digging this weekend to see exactly whats what with it then,

It seems nothing the chap told me has been incorrect so far, so I am inclined to believe him but there is nothing like seeing for yourself,

Its a well sorted car, got fully adjustable suspension on it and its lowered (possibly too much) but what the hell, handles really well!

I'll try and work out:

If its been chipped and if so, who by,

Exactly what the induction kit is,

If its got any additional mods like a bleed valve (almost certain thats a no, but will check)

The cat back is veilside and that I am pretty certain of since I've looked at it and the pictures and its the same.

So, if the boost is under ecu control, will it be safe to change the downpipes? Guess a restrictor ring will still be needed, I certainly don't want to risk blowing the turbos until I'm in a position to replace them with something better,

cheers, thanks for the help,

Louis

[Chillipower]

Ok I did take a quick look over the weekend,

Its definately got the 1st cat on it (can see it from the engine bay) - not sure about the second as I didnt get a chance to jack the car up,

There is no sign of a manual bleed valve as far as I can see,

I think the de-cat/downpipe replacement puzzle may be answered for me, from what I have read elsewhere it seems that:

With the j-spec, its worth doing a de-cat for the second cat, but leaving the 1st cat on still as this helps regulate boost correctly. Replacing both cats means you need a restrictor ring (which effectively negates the 1st cat removal) otherwise you might get boost spikes/creep and with the more fragile ceramic turbos this could well lead to premature failure, that seem right?

so for me, seems like I need a second cat de-cat pipe, can anyone recommend one?

I've seen the Rod Millen pipe recommended, it wasnt clear if that was a 1 or 2 cat replacement, I'll have to find out.

I guess if there is no decent single cat repalcement pipe then I will get the double de-cat and restrictor as before,

By the way, is there an easy way to identify if I have an odb-i or odb-ii ecu?

thanks for all the help, squeezing the most out of my current set up will do me for a while, until I am ready for some crazy upgrade - a slightly slower working car is a lot better than a faster but dead one!

Anyway, I've clocked the racelogic traction control system and I'm thinking that could be a very effective way to make the car faster for not a lot of £, so that might be the next mod to do :)

cheers,

L

[Martin F]

- not sure about the second as I didnt get a chance to jack the car up,

No need to jack the car up, just get on your hands and knees right about the drivers side door and you should be able to see it underneath if it is there.

[Chillipower]

Ok cheers for that,

the cars extremely lowered so I thought that might not be possible, but I'll give it a go tomorrow and get back to you,

cheers,

L