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  • 2 weeks later...

okay, a few things i wanna ask.

is it possible to fit the GReedy dump pipes with the engine in the car? also, will they bolt straight onto the stock turbos? or i should wait untill i get 2530s?

also, i was told, HKS dumps work better with HKS turbos( i know their split is too short), also with the HKS front pipes( Y piece). is that true?

cheers guys!

  • 2 months later...
  • 1 year later...

It's great to see that the SAU search button works well :)

I am not sure if you are still active or not but thanks for all of the information Lucien

I've just ordered a Greddy Extension pipe from Advan Performance Centre and looking forward to the installation. The guys there are very helpful :down:

I have a pair of Greddy low mount turbo so I don't have much option beside the Greddy or CES racing or some other custom extension pipe. A lot of people are saying that the Greddy/CES pipes will bring on boost earlier than other aftermarket pipes without the separated wastegate pipes. How is this possible when during boost build up the wastegates should be closed anyway?

My car is mainly used for track days. I am planning to get the local exhaust shop to weld 2 removable plates on the 2 wastegate pipes. The plates will be removed at the track to vent the wastegate exhaust out into the atmosphere. I will get them to fabricate 2 little pipes to hook up to this opening and direct this gas somewhere safe, away from any plastic stuffs. Has anyone done this? Are there any benefits and most importantly any potential problems in doing this?

Edited by 9krpm
It's great to see that the SAU search button works well :down:

I am not sure if you are still active or not but thanks for all of the information Lucien

I've just ordered a Greddy Extension pipe from Advan Performance Centre and looking forward to the installation. The guys there are very helpful :laugh:

I have a pair of Greddy low mount turbo so I don't have much option beside the Greddy or CES racing or some other custom extension pipe. A lot of people are saying that the Greddy/CES pipes will bring on boost earlier than other aftermarket pipes without the separated wastegate pipes. How is this possible when during boost build up the wastegates should be closed anyway?

My car is mainly used for track days. I am planning to get the local exhaust shop to weld 2 removable plates on the 2 wastegate pipes. The plates will be removed at the track to vent the wastegate exhaust out into the atmosphere. I will get them to fabricate 2 little pipes to hook up to this opening and direct this gas somewhere safe, away from any plastic stuffs. Has anyone done this? Are there any benefits and most importantly any potential problems in doing this?

you are spot on. for years I've had otherwise intellignet folk giving me the spiel that sperate wastegate pipe helps boost build which is just plain rubbish. as you pointed out whilst boost is building wastegate is (or should be) firmly shut so split or merged makes bugger all difference. once the gate is open it means you are at target boost so it makes little difference. having a big open pipe does help as the quicky you can let the gas expand after exiting the turbine the faster it moves the better off you are.

now a days I prefer the big mouth tomei dumps. but the trust ones are good too. sorry I couldn't help you out in a hurry. :) I'm sure you will like them. my only real criticism of the trust dumps and fronts is that they are mighty heavy, so make sure you use all the brackets etc to take that weight off the turbos. the reason for that weight is they use quite thick stainless which is a good thing too.

as for making the gates dump atmo for the track I would not bother. so much effort and it will butcher your pipes and not offer much if any gain. if you really want some track sound I would suggest leaving the front pipes and dumps alone, but change the cat back section between street and track. for street you can have a set-up with a cat and quiet-ish cat back exhaust and for track loose the car and run straight pipe with just 1 muffler.

I know you did your best for the given situation and was very helpful too :D Thanks for all of your help Beer Baron. Advan just happen to keep one in stock for a clearance price. Hopefully the local freight will get it here before this weekend :P

I agree with you R. There are a lot of highly intelligent pple in this game :). If anything the larger 1 piece extension pipe should help with the boost build up better than the 2 pieces (I am working on the assumption that the main exhaust pipe on the greddy is smaller than the single one pipe). The 2 piece should have better top end torque if built correctly. I have a custom extension pipes with a Mines collector. I had to use a custom extension pipes for the greddy turbo because the Mine extension pipes were designed for Gattett type turbo. I changed to a larger pair of greddy and had issues with tubo dump gasket leak. I am not entirely sure if its because of the supplied greddy nuts/studs, greddy gaskets, the flanges on the custom extension pipes are not wide enough or installation issues. I would hate to do this again so I ordered covered all bases to prevent this issues again.

At the moment my engine setup gets +ve pressure at 2100rpm with the race exhaust and around 6-700rpm later with the street exhaust. My torque curve rolls off a bit at top end. I am not sure if this is because I had semislick on the roller and a weak clutch or a slightly restrictive exhaust or small low mount turbs. I've been wondering if the screamer pipes will help with the top end torque. I doubt that there will be enough room to do this but it will be good to see if anyone had attempted to squeeze a sreamer pipe into the Greddy extension pipe.

Edited by 9krpm

Just so as not to start a new topic, is it worth replacing the dumps if i'm only looking for 300-320kw? got a 3" cat back on it.. (standard cat though) should i just replace the cat? i dont mind a few less horses but dont want it to be a big restriction

Just so as not to start a new topic, is it worth replacing the dumps if i'm only looking for 300-320kw? got a 3" cat back on it.. (standard cat though) should i just replace the cat? i dont mind a few less horses but dont want it to be a big restriction

Replace the std cat with something decent then see if you need to change dumps. Std/compliance cat is a real strangler.

well the thing is you aren't going to get anywhere near 300-320rwkw with stock turbos. so if you are replacing the turbos, replace the dumps. nice tomei dumps are awesome and under $700 to your door. or there are cheaper knock offs around but none of them have filled me with much confidence. given they are the most important piece of the exhaust I would spend the money on nice ones.

I know you did your best for the given situation and was very helpful too :D Thanks for all of your help Beer Baron. Advan just happen to keep one in stock for a clearance price. Hopefully the local freight will get it here before this weekend :P

I agree with you R. There are a lot of highly intelligent pple in this game :). If anything the larger 1 piece extension pipe should help with the boost build up better than the 2 pieces (I am working on the assumption that the main exhaust pipe on the greddy is smaller than the single one pipe). The 2 piece should have better top end torque if built correctly. I have a custom extension pipes with a Mines collector. I had to use a custom extension pipes for the greddy turbo because the Mine extension pipes were designed for Gattett type turbo. I changed to a larger pair of greddy and had issues with tubo dump gasket leak. I am not entirely sure if its because of the supplied greddy nuts/studs, greddy gaskets, the flanges on the custom extension pipes are not wide enough or installation issues. I would hate to do this again so I ordered covered all bases to prevent this issues again.

At the moment my engine setup gets +ve pressure at 2100rpm with the race exhaust and around 6-700rpm later with the street exhaust. My torque curve rolls off a bit at top end. I am not sure if this is because I had semislick on the roller and a weak clutch or a slightly restrictive exhaust or small low mount turbs. I've been wondering if the screamer pipes will help with the top end torque. I doubt that there will be enough room to do this but it will be good to see if anyone had attempted to squeeze a sreamer pipe into the Greddy extension pipe.

sounds like you have a pretty decent set-up. I don't have a lot of experience with the trust twins on GTRs. been in a few with trust singles and one or two with the twins but not enough to really get a feel for them. having said that I'm running a single trust T518Z on my silvia SR20 and it's awesome. very good spool up and makes 235rwkw without much boost. I can imagine a pair of the smaller ones would be a good thing on an RB26.

  • 2 months later...

*digs up old thread*

Ok, so having joined the highly non-exclusive GTR ‘exhaust wheel found in cat converter’ club, I have obtained from a forum member some replacement turbos – specifically, HKS 2530’s (cheers Ben). Having removed the stock turbo’s and dumps, I have noticed three important things:

1) the OEM cast dumps look very restrictive;

2) the dump pipes would be pretty much impossible to remove without removing the turbos, and all associated procedures; and

3) there is not a lot of clearance between the front dump pipe and the rear turbo housing.

So, I have decided (since the turbos are off anyway) to replace dumps with freer-flowing aftermarket items – doing this mod on my z32 TT got great results, so well worth it (I’m also going to grind out my manifolds slightly like others on here have done).

REPORTED PROBLEMS

So I did a search on this site to find out if there are any “issues” I need to look out for, and two problems in particular presented themselves in using aftermarket dumps.

1) One person reported that they had clearance issues between the back of the dump pipe and the rear turbo housing. Their solution was to beat an indentation in the back of the front dump pipe to allow clearance to install (ouch).

2) Another person had a different issue – not quite clear what – but it required actually cutting and shutting the flange on the dump to re-orient it somehow.

In both cases, the problem was put down to buying “cheap ebay dump pipes”. Fair enough, you get what you pay for.

BUT I am not prepared to do either of these things to modify what is meant to be a “bolt on” mod. I’d rather shell out the extra $$ and save hours (and $) stuffing around under the bonnet any more than I already have.

THE OPTIONS

So far the options I have found are:

$189 (starting bid), JDM racing on ebay – has anyone bought a set of these, and installed them without any dramas?

$399 – JJR/Just Jap dumps – search has revealed mixed reports, one person said they had troubles, another person said they fitted perfectly. Just Jap are confident they will fit correctly. In any case, having bought stuff from Just Jap before, I know that if I did have any issues, they’d refund my money no questions asked, I just want to save any hassle.

A couple of posts reckon the r34 GTR dumps are superior to r32/33 – I don’t even want to speculate as to how I would obtain a set of those.

$800 – HKS – probably guaranteed to fit and work well, but I don’t really want to shell out eight hundred bucks for some pipes for no real benefit.

MY DUMB QUESTIONS

What other bolt-up options are out there? If there is a cheaper option that bolts up I’m keen, anything has to be better than the OEM ones, but if I can’t find anything better I’ll probably go with the JJR option.

I note my new turbos have a divorced wastegate and exhaust section, so any dumps that had a separator in the middle that projected past the flange would have to be removable (by removable I mean unbolting, not angle-grinding).

Alternatively, if you are selling an aftermarket set of r32 GTR dumps, or stock r34 GTR dumps, in good nick, please feel free to shoot me a PM.

Andrew

my opinion is tomei dumps. they are beautiful and everyone I know that has used them has had great results. one or two even went from HKS or HKS copy dumps to the tomei ones and found improvement. they are not the cheapest though.

my opinion is tomei dumps. they are beautiful and everyone I know that has used them has had great results. one or two even went from HKS or HKS copy dumps to the tomei ones and found improvement. they are not the cheapest though.

Cool, tomei do the sort of single-pipe ones, "bellmouth" I think people on here refer to them as? (HKS and JJR are the split ones)

I have seen them around $700 a pair, I think, any better prices than that?

I too just looking at the design of the split dumps and the turbo housings Garrett turbos have questioned their performance (or mystical improvement in performance).

As someone mentioned before when you are on the throttle the wastegate is closed, it may be possible that changing fast between gears (or maybe flatshifting) that the wastegate gases may interfere with the exhaust flow. But I have not seen anything set in concrete other than peoples opinions that there is an improvement be it in improving turbo spool or overall power.

Another thing I noticed is that the face of the housing does not seal with the face of the split dumps. Below is a link to a thread from gtr.co.uk:

http://www.gtr.co.uk/forum/102718-garrett-...st-housing.html

I have looked at pictures of the housings for T517Z's, GT2860's and ARMS 7660 and the above link shows the rear end of a HKS 2530. On all of them bar the HKS 2530 the rear end does not have a flanged face that seals with the split dump. So to me it seems as if this is another reason not to bother with split dumps, if it is not sealed you are going to get interference which is what everyone is concerned about, it seems.

I don't know, I would love for split dumps to make a difference but it does not seem to make a lot of sense to me.

Sorry if I am off topic. But, what do other people think?

Mike

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