Guest GotBoost Posted October 31, 2008 Share Posted October 31, 2008 Hi Guys, A friend is looking for a mild upgrade to a standard 1994 JDM Supra tt manual, he wants to keep the CAT for MOT time, so i would like some advice on the following setup for him: Remove centre/rear cat ( leave 1 in place ) Fit FCD Fuel pump Boost controller set to 1-1.1bar FPR setup on dyno This should yeild approx 380bhp, but i have a little concern about the restriction caused by the remaining CAT and EGTs, Im thinking along the lines of turbocharger reliability. Can someone advise me on this please? Or reccommend a better solution? My friend has been contemplating the Superchip upgrade, but i again have concerns about EGTs and reliability on the OEM turbos/ cats/ fuel pump etc. They claim ~380bhp for around the same price as the above upgrade, though i cant justify this figure. Craig Quote Link to comment Share on other sites More sharing options...
Thorin Posted October 31, 2008 Share Posted October 31, 2008 The first cat is the most restrictive and should be removed first, and I'd limit boost to 1.0 bar if you're leaving the cat in place (EGT's should be OK but I wouldn't want to risk higher). Fuel pump is a good idea, I'd go for an OEM UK spec pump over the Walbro, but they are more expensive. Forget the FPR. There is no "superchip" for the Supra, all they do is fit an FCD and a bleed valve to up the boost. Quote Link to comment Share on other sites More sharing options...
Guest GotBoost Posted October 31, 2008 Share Posted October 31, 2008 Cheers for the reply, Since we'll be keeping it to 1bar, then we may not get the FPR, if we were going above then i would recommend it to him. This will be on the dyno so i can give before and after results, since it would all be strapped down i would have advised the FRP for quick adjustment if we were going over 1bar. Looks like the OEM mapping is very conservative if the MAF signal can be pegged at 1bar equivalent and actually run 1.2-1.4. Any idea of the boost increase with just removing the front cat? Im guessing it wont get to the 1bar we require so a MBC/EBC would be required. Any reason you rec the OEM UK pump over the Walbro? I have always used Walbro and not had any issues. Thanks for the help. Craig Quote Link to comment Share on other sites More sharing options...
Thorin Posted October 31, 2008 Share Posted October 31, 2008 I would never recommend an after-market FPR for BPU levels. You do not need to increase the fuel pressure, at BPU the cars generally run a bit rich anyway, and they simply cannot be relied on. Just removing the front cat would only increase the boost to 0.8-0.9 depending on how restrictive the rest of your exhaust is I would guess. The OEM pump actually performs better than the Walbro. The downsides are that it costs a lot more than the Walbro and pulls more amps at the same voltage I believe. Quote Link to comment Share on other sites More sharing options...
TTRickeh Posted October 31, 2008 Share Posted October 31, 2008 Any idea of the boost increase with just removing the front cat? Im guessing it wont get to the 1bar we require so a MBC/EBC would be required. Craig Depends partially on which cat-back exhaust you have I think, I have a 2.5'' double decat with a restrictive exhaust and make 0.9bar. Quote Link to comment Share on other sites More sharing options...
Guest GotBoost Posted October 31, 2008 Share Posted October 31, 2008 Cheers guys, You can lower fuel pressure with an Adjustable FPR as well as raise, since you say its not needed i'll take your advice. Supras are not something i have dealt with before, and dont plan on dealing with in the future, just trying to help out a mate. I should have mentioned this in the OP, the car is TOTALLY standard and he wants to keep it as close to standard as possible, but does want a power upgrade. When i have been researching the prices etc for decats, FCDs, fuel pumps etc it looks like he is not going to be willing to spend this kind of money, and is also intent on keeping the OEM exhausts. I guess he has 2 real options: 1- leave the car as is 2- Do things correctly and change full exhaust. FCD, 1.2bar restrictor, pump, EBC, install and setup. This will come to siro £1000 and he's not going to want to spend that much. I guess the boost could be upped to 0.9 bar or something with the OEM 2 cats, but its not something i would like to reccommend. Great forum here guys, lots of great info and lots of people giving advice, fast response too!!! I deal with Hondas mainly, just said i would look into this for a mate. Thanks for the help and advice, if anyone has a Honda they need help with, put them onto me ( http://www.GotBoost.co.uk ) If anyone has any other alternatives please let me know. Thanks alot guys, and keep up the great site!! Craig Quote Link to comment Share on other sites More sharing options...
Thorin Posted October 31, 2008 Share Posted October 31, 2008 If you haven't already, click the underlined BPU link and have a read through. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 31, 2008 Share Posted October 31, 2008 Alternative's, a XS Power SS exhaust can be had for £250, decats for less and even SH, if it has lowish mileage then the pump should be OK, however if he wants to leave the std exhaust then this will also limit power/boost and even if you remove both cats, i still think its going to have a fair impact, if he goes for full decat and exhaust then it will need a restrictor ring, J specs don't need a boost controller usually as the wastegates are too small and as soon as exhaust restrictions are removed, then you will suffer overboost. If you do run a boost controller with exhaust restrictions then you are prone to EGT issues. Quote Link to comment Share on other sites More sharing options...
bigbloodyturbo Posted October 31, 2008 Share Posted October 31, 2008 what is a safe boost level for a jspec with a 1st deact and the 2nd cat still inplace? i was going to put both decats in but i'm now going to leave the 2nd cat inplace to limit boost and then turn it up with my controller but if you say i'm going to have egt issues then at what boost levels will that occur? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 31, 2008 Share Posted October 31, 2008 what is a safe boost level for a jspec with a 1st deact and the 2nd cat still inplace? i was going to put both decats in but i'm now going to leave the 2nd cat inplace to limit boost and then turn it up with my controller but if you say i'm going to have egt issues then at what boost levels will that occur? It often depends on the individual car, any restriction in the exhaust department is going to have temperature consequences, i imagine the std boost is set to avoid this with both cats and std exhaust in place, i would hazard a guess that 1BAR should be OK with just second cat, but an EGT gauge is the only sure way to tell. Quote Link to comment Share on other sites More sharing options...
Guest GotBoost Posted October 31, 2008 Share Posted October 31, 2008 Thanks for the good advice guys, yes i did read through most of the technical stickies, interesting reads. i had some specific questions about leaving the cats in. My friend is going to save a little then upgrade all at once. Thanks again. Craig Quote Link to comment Share on other sites More sharing options...
Nic Posted November 1, 2008 Share Posted November 1, 2008 I'd go for an OEM UK spec pump over the Walbro, but they are more expensive. The UK and J-spec pumps are a different fit, although they can be bodged to fit. Quote Link to comment Share on other sites More sharing options...
Thorin Posted November 1, 2008 Share Posted November 1, 2008 The UK and J-spec pumps are a different fit, although they can be bodged to fit. Ah yes, I should have mentioned that, but it's no big deal Quote Link to comment Share on other sites More sharing options...
Harris25 Posted July 29, 2009 Share Posted July 29, 2009 will the car still go through the MOT with 2nd cat in place and first removed? Quote Link to comment Share on other sites More sharing options...
Thorin Posted August 3, 2009 Share Posted August 3, 2009 Old thread. Should be fine yes. Quote Link to comment Share on other sites More sharing options...
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