Justin Posted August 20, 2002 Share Posted August 20, 2002 Today I sent my car to the garage to have the front cat replaced with a Chris Wilson downpipe. I just took it for a test blast and oh my god they seem to have swapped out my engine for a Formula 1 Ferrari engine! It goes like absolute stink now. I floored it and nearly ended up in the back seat. The throttle response is instant and turbos spool up so much faster. My PSI went up from the usual 12 to 17.6 (need to keep my eye on that). Just as I was getting a bit bored with the power up to now and waiting for it to kick in a second after stamping on the throttle CW gives me a shot in the arm. Nice one Chris another happy customer in a Supra. Trouble is my local launch strip seems quite a bit shorter with this new power. Looks like I may need some UK front brakes. For those of you who haven't done the de-cat yet, you gotta do it. Only £150 odd quid. Below is a representation of what my face must have looked like doing the test run. :flame Dev Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted August 20, 2002 Share Posted August 20, 2002 Time for me to get the VISA card out then! Was that £150 just for the pipe or did you get it fitted for that? Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 20, 2002 Share Posted August 20, 2002 its good init? price is more like £300 for cat pipes, £70 fuel cut, £??? boost + egt guage, and fitting (and a cat back zorst if u dont already have one). then £150 of fuel just for a laugh. well worth it tho. Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 20, 2002 Share Posted August 20, 2002 go find some long bridges (or any encolsed place) now Quote Link to comment Share on other sites More sharing options...
Branners Posted August 20, 2002 Share Posted August 20, 2002 Decat really does make a massive difference on an import. Only problem is you will be going so much quicker now that standard import brakes will not stop you after a few heavy stops. Uprate the pads and get the fluid changed now otherwise you might be in for a few Brown Alert moments. JB Quote Link to comment Share on other sites More sharing options...
Justin Posted August 20, 2002 Author Share Posted August 20, 2002 Originally posted by John Packham Time for me to get the VISA card out then! Was that £150 just for the pipe or did you get it fitted for that? Just for the front pipe John. I only took it to the garage to do because they have a ramp to get underneath and tools to get the bolts off. They'll only charge me £20 for the fitting. But to be fair I did already have the boost gauge (£120) Mid HKS de-cat (£150) Fuet cut controller (£75) and Blitz exhaust (£550) But still if the front cat is removed you WILL notice the difference. Quote Link to comment Share on other sites More sharing options...
Justin Posted August 20, 2002 Author Share Posted August 20, 2002 Errrrrrrrrm yes how much were a set of those front UK brakes that Phil was sorting out last time? Quote Link to comment Share on other sites More sharing options...
AJI Posted August 20, 2002 Share Posted August 20, 2002 I have just had my exhaust de-catted by Chris Wilson on Monday and yes the difference is very noticable. Chris does a very nice job and also sorts out other problems while he's got the car on ramps. The power is much more instant and it feels much more quicker through the rev range. Quote Link to comment Share on other sites More sharing options...
Adam Kindness Posted August 21, 2002 Share Posted August 21, 2002 i agree... my response was much the same as Justins I waited weeks and weeks to get back and fit the stuff.... all got done in two days Both Cats out - CW downpipe and HKS front SuperDrager On BoostCut removed Speed Limiter removed Wider Tyres On.... Fely like a diff car... was luvly for a day... then i need new plugs... Now its luvely again Quote Link to comment Share on other sites More sharing options...
Terminator Posted August 21, 2002 Share Posted August 21, 2002 Glad you like it Justin. Was it Glen who fitted the pipe? I remember getting my car as stock. It felt bloody quick for a while, then I got used to it and it felt slow. Cats out and it felt fast again. Now ....………. That's the trouble with power mods, you get used to them. I just have to keep watching the rear view mirror to see how quickly other cars vanish to remind myself how fast it is. My favourite manoeuvre is roundabouts and their exits, especially when I have been buzzed by some pratt before the roundabout, everything behind just disappears, I don’t care if they catch up later, because I can do it to them again at the next roundabout and again and again………:flame Dev Quote Link to comment Share on other sites More sharing options...
randy Posted August 21, 2002 Share Posted August 21, 2002 Justin, Way to go pal!! It makes you smile so much after decat, and even more if you get a boost controller!! But Yes!!! We need better brakes, the brakes we have are crap and are soft on response. I am going to do my brakes immediately! Have fun with your ride. Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted August 21, 2002 Share Posted August 21, 2002 Genuine question, Do these trick cat-back systems really produce performance or are they all show and sound? I like a car to look good but I'd rather spend on performance than styling. Quote Link to comment Share on other sites More sharing options...
Patrick_Devlin Posted August 21, 2002 Share Posted August 21, 2002 I've been reading all the posts on CW pipes and de-catting etc... and I'm extremely tempted, I will be chacking the finances as soon as to free up a few quid for the mods. Can I just clear up one question? How much difference will replacing just the front cat with A CW pipe whilst retaining the remainder of the stock J-Spec exhaust? I intend to go for the whole shooting match but will only be able to do the mods in stages. Quote Link to comment Share on other sites More sharing options...
randy Posted August 21, 2002 Share Posted August 21, 2002 Trick?? I don't think so my friend!! The downpipe eliminates a huge exhaust restriction which helps the car get rid of burnt gasses faster thereby the engine can breathe a lot more efficiently. Do it then tell us! Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted August 21, 2002 Share Posted August 21, 2002 Originally posted by John Packham Genuine question, Do these trick cat-back systems really produce performance or are they all show and sound? I like a car to look good but I'd rather spend on performance than styling. Imagine it as removing a big blockage from the middle of your exhaust. Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted August 21, 2002 Share Posted August 21, 2002 Originally posted by Martin F Imagine it as removing a big blockage from the middle of your exhaust. More like a massive blockage, (or 2!). You have to see inside one of these things to appreciate how constipated the engine must feel! I'm beginning to think Chris is also into plastic surgery as all his customers end with the same Yours Another happy CW customer Quote Link to comment Share on other sites More sharing options...
Induction Posted August 21, 2002 Share Posted August 21, 2002 This all sounds good stuff. I've got an HKS front pipe and Super Drager coming soon, but the reason I left out a down pipe was because I was told that when the second cat is removed and an exhaust system fitted, the Supra relies on the first cat for back pressure. I've also been told (and I'm sure I've read it somwehere on a site) that it can cause overboost and boost spikes. If, judging by the posts here, this isn't true then I'll get a downpipe as well, definitely. Anyone clear this up for me? If I got a downpipe, is a boost cut controller a neccesity (any other things needed?), and, bearing in mind that I've got a UK spec car, does this make a difference to the whole downpipe situation? Thanks Quote Link to comment Share on other sites More sharing options...
Adam W Posted August 21, 2002 Share Posted August 21, 2002 CW downpipes are designed to be slightly restrictive, to stop J-specs from overboosting. With a UK car, I believe the wastegate dsign is different so that is no longer a problem. With this in mind, go for a 3" diameter pipe (assuming the rest of your exhaust system is the same - I think the HKS stuff is) to move as much gas as possible. I think a Boost cut controller (also known an FCD or fuel cut defender) will be required, hopefully someone can confirm. Pete Betts unit is well liked and has a good reputation. Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted August 21, 2002 Share Posted August 21, 2002 A FCD will be required and from what I've heard, a UK car doesn't suffer the same overboosting problems as a J-spec. Go for it! Quote Link to comment Share on other sites More sharing options...
Keith C Posted August 21, 2002 Share Posted August 21, 2002 Originally posted by Adam Wootten CW downpipes are designed to be slightly restrictive, to stop J-specs from overboosting. With a UK car, I believe the wastegate dsign is different so that is no longer a problem. With this in mind, go for a 3" diameter pipe (assuming the rest of your exhaust system is the same - I think the HKS stuff is) to move as much gas as possible. I think a Boost cut controller (also known an FCD or fuel cut defender) will be required, hopefully someone can confirm. Pete Betts unit is well liked and has a good reputation. The UK-spec pipes are different anyway, to allow for the 2nd sensor in front of the no.2 cat. Quote Link to comment Share on other sites More sharing options...
Branners Posted August 21, 2002 Share Posted August 21, 2002 An import with a decat and performance exhaust (Blitz Nur etc) will overboost, seems to vary from car to car. I had a Rod Millen down pipe which was meant for a US spec but was adapted to fit a UK spec which brought the boost up to about 14psi but I had the stock exhaust system. I then replaced the stock exhaust system with a Blitz nur spec with the baffle in and hit 18-19psi. If I took the baffle out it went up to 21psi. I ran the car like that for quite a while and I eventually put in a HKS s-type IC just to keep the charge temps down. I ran that car like that for about a year with no problems and it really did shift. The turbos did eventually go but to take that level of abuse for a year was good going. If you are going to decat you may as well remove both. If you can accept higher boost then a 3" downpipe is okay, if you are really worried go for a 2.5" downpipe. The exhaust will also have a lot to do with what boost you hit. The hipers are very free flowing for instance. JB Quote Link to comment Share on other sites More sharing options...
Induction Posted August 21, 2002 Share Posted August 21, 2002 I knew I'd read it somewhere - this is off the TDI site http://www.tdi-plc.com/toyota_supraMk4.html#TOYOTA SUPRA TWIN TURBO JZA80 1994 on (2JZ-GTE) Stage 1 option: High-flow front-pipe. (Also removes 2nd Cat) Fitment of this pipe will give around 10bhp due to the removal of the 2nd catalyst and increase in in bore size. Turbo lag is also reduced over the original pipe. Most vehicles will still be legal for UK MOT's providing the 1st cat is in good condition. Modifications will be needed to fit on UK models as the lambda sensor boss is not present. This is a relatively straightfoward procedure to carry out and can be done here if necessary. £145.00 Please note: We do not reccomend removal of the 1st catalyst (on vehicles using stock turbos) due not only to the legality issue but also the fact that the Twin Turbo Supra uses the cats as a method of boost control. Removal of both cats can lead to excessive boost levels and/or 'boost creep' (especially on Jap models) due to the vehicle being unable to control exhaust flow. Cat removal pipes are available that can sometimes keep boost pressures reasonably low but they need to be made from a relatively small diameter pipe (2.5") to still present a restriction to flow. In our opinon this is pointless and retaining the stock 1st cat and using the very large (3") HKS front pipe usually achieves a similar result at a cheaper cost, whilst still keeping the vehicle legal and guaranteeing that boost levels remain safe for the engine. Quote Link to comment Share on other sites More sharing options...
Alex Posted August 21, 2002 Share Posted August 21, 2002 Right, There is no point in just removing 1 cat. J-specs should really have the twin CW pipes. UK/US spec can have bigger bore pipes. You will need an FCD (from TRL) You MUST fit a boost gauge. If you find the boost spikes over 1.3 then I would recommend that you buy a restrictor plate from CW. By removing the cats you 1. Reduce back pressure which reduces spool time. 2. Reduce the heat build up around the manifold and turbo's prolonging their lives and protecting against Detonation. 3. More power cause it boosts faster and higher. 4. A deeper louder zaust note What it costs... 1. You can run slightly lean. 2. You'll get bitten by the tuning bug and have to carry on doing other stuff. 3. The wife will leave you if you don't keep number 2 in check! As for putting a decat in with a stock cat back zaust ...not sure all I can say is that the benefit won't be as great as if you have a bigger bore cat back. Hope that clarifies things.... Quote Link to comment Share on other sites More sharing options...
Alex Posted August 21, 2002 Share Posted August 21, 2002 Induction. HKS don't make a decat down pipe so of course they don't recommend fitting one. They'd rather you pay for a really expensive boost controller to up the boost. Basically I would not follow the TDI plan as its not designed to give you best VFM. But its your choice. If your car is a J-Spec 93-95 it can be fully decatted and pass an mot...depends on the guy that tests it and his reading of the rule book. Others just put the second cat back in when they go for an MOT....which takes about 10 mins! Quote Link to comment Share on other sites More sharing options...
Terminator Posted August 21, 2002 Share Posted August 21, 2002 Induction, The HKS pipe is a three inch, when you add on of CW's front pipes 2.5 inch you are likely to go over 18 psi if you have a performance exhaust. Chris can provide a restroctor ring which will keep the boost safe more inline with the two pipe CW system. The ring does work, it lowered my top level from 1.4 to 1.1 bar on a J spec. Quote Link to comment Share on other sites More sharing options...
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