Guest Roger NE Posted October 25, 2013 Share Posted October 25, 2013 Has anyone ever measured the power increase on a stock 2JZ-GE having removed all the Cats? Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 25, 2013 Share Posted October 25, 2013 If nobody's measured it (or heard of somebody that HAS), what would people estimate . . . about 10 bhp? Quote Link to comment Share on other sites More sharing options...
Graham1984 Posted October 25, 2013 Share Posted October 25, 2013 0000000000000000000000000000000.12738282 bhp. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 25, 2013 Share Posted October 25, 2013 Well I seem to remember reading reports people of people in the USA that had done dyno checks having removed the Cats on a 7M-GE that it was about 10 bhp increase . . . so can't see why it would be any less on the 2JZ-GE ? Quote Link to comment Share on other sites More sharing options...
scott87 Posted October 25, 2013 Share Posted October 25, 2013 I reckon 20bhp for 1000quid Quote Link to comment Share on other sites More sharing options...
JasonR24 Posted October 25, 2013 Share Posted October 25, 2013 I knew someone with a decatted NA and my NA was no different in speed.... Mine had Cats.... Quote Link to comment Share on other sites More sharing options...
walbertonio Posted October 25, 2013 Share Posted October 25, 2013 Aye, as above, hunting for horses from an NA is an expensive game. You'd probably get a few horses from removing the cats, but the better benefit would be the sound I would say. Quote Link to comment Share on other sites More sharing options...
Graham1984 Posted October 25, 2013 Share Posted October 25, 2013 You may get 15-20 bhp from a cat back exhaust, full decat and an upgraded manifold but that is if you are lucky. Being near on 20 years old a healthy running motor will trump and upgrades IMO. Bang for buck it is pointless,did I do it still Quote Link to comment Share on other sites More sharing options...
monkey76364 Posted October 25, 2013 Share Posted October 25, 2013 My na is having extra power added with the na-t but with all the stuff I'm doing we are talking 20k Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 25, 2013 Share Posted October 25, 2013 I've actually got a Mk3 N/A Supra, with the 7M-GE engine . . . I removed the Main Cat about 10 years ago, and noticed improved performance at the top end, but low end torque was now bad. Then I discovered that for the earlier UK models Toyota fitted a Catless front section . . . which has a box that replaces the main Cat - this isn't restrictive like the Cat, but gives the engine the back-pressure it is expecting. (these OEM front sections are actually readily available from most exhaust companies) When I fitted this special Non-Cat front section, I retained the improved top-end performance from removing the Cat . . . but re-gained the low-end torque I'd previously lost. The point is I'm about to replace my 7M-GE with a 2JZ-GE, which at the end of the day is just a more reliable version of the same engine (VERY similar design) . . so am keeping my stock Catless exhaust system. So I'm presuming I would get a similar power gain . . . . Quote Link to comment Share on other sites More sharing options...
Graham1984 Posted October 25, 2013 Share Posted October 25, 2013 It makes it rev/pull a lot more freely than stock but depending on your exhaust it can be extremely loud too, I have had a mines ecu on mine for a while now so I can't really remember what the stock feel was like now. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 25, 2013 Share Posted October 25, 2013 Did someone mention power increase and N/A in the same sentence again.... Quote Link to comment Share on other sites More sharing options...
scott87 Posted October 25, 2013 Share Posted October 25, 2013 Better flowing intake can help like an upgraded forced ram. Then getting rid of of both under silencers and both cats and a manifold will help loads. Then meth. And that's about it in my opinion. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 25, 2013 Share Posted October 25, 2013 (edited) It makes it rev/pull a lot more freely than stock but depending on your exhaust it can be extremely loud tooWell as I mentioned, I have a complete Toyota exhaust fitted that is CATLESS . . . so it's not any louder ! Just develops more power without the Cats . . . and I'm pretty sure it will do the same job when I fit my 2JZ-GE and attach the same exhaust As per my original post, I just wondered if anyone had any figures . . . as I said, I seem to remember about 10 bhp increase quoted when removing the Cats on the 7M-GE, so I'm guessing it should be about the same on the 2JZ-GE Edited October 26, 2013 by Roger NE (see edit history) Quote Link to comment Share on other sites More sharing options...
Tyson Posted October 26, 2013 Share Posted October 26, 2013 Well I'd be sceptical if it was any more 5bhp TBH. As for the 7M surely you could look at the manufactures stats and compare the Jap one to the UK one which has the catless front section to see what the difference was. Quote Link to comment Share on other sites More sharing options...
Guest SupraV8 Posted October 26, 2013 Share Posted October 26, 2013 Well I'd be sceptical if it was any more 5bhp TBH. As for the 7M surely you could look at the manufactures stats and compare the Jap one to the UK one which has the catless front section to see what the difference was. Mine made 12hp more on the top end, but lost around 4hp in the midrange. 2jz-ge, 90k miles, not looked after! Dastek dyno, motorscope. Quote Link to comment Share on other sites More sharing options...
Big Supes Posted October 26, 2013 Share Posted October 26, 2013 I would get a 75 shot of nitrous on an NA. Prob the cheapest way of getting power for when you need it. Quote Link to comment Share on other sites More sharing options...
listy Posted October 26, 2013 Share Posted October 26, 2013 Any increase wouldn't be very noticeable, if at all to be fair. I never noticed a difference when I decated my old NA. Quote Link to comment Share on other sites More sharing options...
Dim Sum Posted October 26, 2013 Share Posted October 26, 2013 There have been many threads about BHP increase for n/a and most if not all comes to the same conclusion. "not worth doing" "TT transplant" "N/A - T" "little increase in BHP" Those are a few common ones and along the way, plenty of sarcasm.. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 26, 2013 Share Posted October 26, 2013 (edited) Mine made 12hp more on the top end, but lost around 4hp in the midrange Many thanks for that . . . given that 10hp increase on the 7M-GE's 200 bhp is a 5% increase, the same percentage on a 2JZ-GE is 11hp, so that makes sense. I'm presuming (from my previous experience with the 7M) that the special Catless exhaust I have will still give the same top end boost, but without losing it lower down the rev range. And to the other comments - I was just wondering what the likely increase was - I'm not actually LOOKING to increase the power . . . I drive way to fast as it is, so why anybody would want more power for road use is beyond me! Plus once I have the 2JZ-GE in my Mk3, so being catless developing around 232 bhp, that's actually the same figure as a stock Mk3 with the 7M-GTE Turbo engine. Edited October 27, 2013 by Roger NE (see edit history) Quote Link to comment Share on other sites More sharing options...
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