As title really, does anyone have one on their car?
Im not really happy with running a 3in (despite even some T88 car running one, and no doubt having mega backpressure becuase of it), but there not much room to say the least with the brake master cyl etc in the way. Its an utter ballache removing the 3in one at the moment.
Anyone done it? Looks like maybe possible if change a few things, maybe the general direction of the DP.
Ta
Do you really need one that size? If the exhaust is too big it will slow down exhaust gasses, if the outlet of the turbo is 3" then you don\'t need a massive exhaust that is bigger as the exhaust gasses will just leave the turbo and then just empty into a huge space and slow down.
You might want to look into how turbos and turbo exhausts work before you answer questions like this. :)
And yes, yes I do need one, actual experience and testing tells me that.
Has anyone on here fitted one? Plenty in the USA but LHD makes its easy for them.
Ok then, fit whatever you want.....
What turbo are you currently running? As far as I can see the main clearance issue will be caused by attempting to get a decent bend past the bulk head. I\'m pretty certain you should clear the rest. (unless you have an aftermarket turbo and manifold that has changed the clearances significantly.)
What does the rest of your exhaust system consist of?
Just convert to LHD like big turbo AE86s do, lots of clearance to fit drainpipes down the right hand side
Quote from: m1tch;703508Ok then, fit whatever you want.....
So you are saying im wrong and what you said is correct? Havent you got a standard FC T2?
Quote from: Brett;703509What turbo are you currently running? As far as I can see the main clearance issue will be caused by attempting to get a decent bend past the bulk head. I\'m pretty certain you should clear the rest. (unless you have an aftermarket turbo and manifold that has changed the clearances significantly.)
What does the rest of your exhaust system consist of?
A stock turbo and manifold would never need more than a 3in really.
Mine is 3in all the way back and seperate screamer, no bends after the DP, and even that is a very smooth shallow bends, but has backpressure still.
Aftermarket turbo and manifold means even the 3in DP is a proper squeeze to clear the brake master cyl etc, bulkhead is no issue, could do 4in all day long if it was only the bulkhead as thats miles away.
Only reason im asking is hopeing someone has tried it for sure and can say if it does or not before I go attempting, as its all off at the min, and if it deffo doesnt I got another way around it that will 100% work, just thats lots more work than just bolting it back on. :)
Quote from: m1tch;703510Just convert to LHD like big turbo AE86s do, lots of clearance to fit drainpipes down the right hand side
Thats a rather ridiculous amount of work, way bigger than my other option that would probably make a 5in downpipe fit, so no I wont do that.
Yeah, standard turbo, custom 3" turbo back exhaust, twin system, will be fitting the T88 next year after I have all the supporting mods, been reaseaching for a while now, exhaust will be custom made at JM garage, he makes exhaust for a living, constantly changing the ones on his 2 rxs to get the best flow, also works with the porche race team, im pretty sure he knows what he is talking about.
At least you will get the flow you want if you want to fit a massive downpipe to be able to clear the rack, less bend etc, it probably is a lot of work, but people do it to be able to fit larger turbos and get the best flow still.
Quote from: m1tch;703604Yeah, standard turbo, custom 3" turbo back exhaust, twin system, will be fitting the T88 next year after I have all the supporting mods, been reaseaching for a while now, exhaust will be custom made at JM garage, he makes exhaust for a living, constantly changing the ones on his 2 rxs to get the best flow, also works with the porche race team, im pretty sure he knows what he is talking about.
At least you will get the flow you want if you want to fit a massive downpipe to be able to clear the rack, less bend etc, it probably is a lot of work, but people do it to be able to fit larger turbos and get the best flow still.
Im not really going to worry about arguing though, everyones car is different and people want to do different things.
I wish you luck with your car
Quote from: m1tch;703612Im not really going to worry about arguing though, everyones car is different and people want to do different things.
Nothing to argue about it, its just facts. Saying you can have a "too big" turbo back system, performance wise, regardless of power or engine, is wrong.
Simple fact is, regardless of the above, a 3in system is a restriction at my boring engines level, and I know if for a fact. God only how bad it is on a RX with proper power.
My question was
"has anyone fitted a 3.5in or bigger downpipe to a RHD FC" and you have replied 5 times so far, telling me it will harm performance, to convert to LHD, the spec your car might be in a year, something about some tuner, and some other odd bit I didnt understand.
But nothing about the question I asked :3Confused
Hopefully someone has done it, but if not, I\'ll just have to wing it like every other bit of tuning I\'ve done to it so far, part of the fun really :)
Think this FC is running a 4" as its matched to the turbo
http://www.youtube.com/watch?v=CiwdnETXCRc
I don\'t know about fitting a 4" exhaust to an fc but if you are restricted by the bulk head on the downpipe could you use a tapered centre section to take the diameter to 4"? This would reduce the back pressure more than your current set up? And I do have to agree with stavfc on this one mitch, as an exhaust system is a restriction on a turbo setup from what I have read on turbo systems, as with drag cars running turbos they have as small of an exhaust coming off the turbo to get rid of the exhaust gases faster. However on an n/a engine exhaust systems can be vitally important, on piston engines they have tuned lengths to help scavenge the other cylinders, all to do with sound waves creating a sucking effect to pull the gases out faster. Also on the rotary front I asked racing beat about exhaust design for my 13 b pp engine and they told me to take the exhaust out behind the front wheel! I still have the email and jim mederer said " the less back pressure, the more power "
The best turbo back exhaust for a turbo car is no exhaust, simple as. The minute you can measure backpressure, and I can, its too small.
Its as much the master cyl thats in the way TBH, that combined with my wastegate position really.
Its a shame you cant see the bay well in that video, as for all I know he has a pedal box and no master cyl then. Also his turbo sits a tiny bit further forward than mine by the looks of it, and i doubt his WG is in the same place.
I can deffo do it, just its debatable if I can without some custom manifold jiggery porkery.
i ran a 3.5 inch down pipe and mid section on my FC. Fitted without problem. Out of interest, how do you know you are getting back pressure? i would have thought egt or some kind pressure gauge before the turbo would be the only true way to tell.
I ran 460 hp at 1.2 bar on a GT40 with a 3 inch system, when i changed to 3.5 all the way to the split by the diff, i had no more power. This was all measured on the same dyno with the same tuner.
What turbo are you running, is it still a TO4E? if so im not sure if you would see any increase in power but then IIRC you run much higher boost levels than most so the bigger exhaust may come into its own above 1.2 bar.
what other tuning have you done with rx7\'s, anything that worked well thats worth sharing?
I have a home brewed backpressure gauge post turbo. Wouldve liked to fit one pre but didnt have time before I popped engine.
Got EGT pre turbo, but that dont tell you bugger all about backpressure really as could be varying factors unless you doing back to back exhaust tests.
The general concensus in the USA seems to be anything about about 325rwhp and you benefit from a bigger than 3in DP for better spool if nothing else.
On piston engines ive experienced bigger than 3in being better at about 450bhp, but then again had another car that seemed fine at 400bhp at 3in, so its not an exact science, lol.
Bigger is always better if it fits, thas for sure.
In answer to the original question I have a 4" pipe from the turbo all the way back so it can be fitted. Engine is a 13B-RE running a T78 which made 530fwhp at 1bar.
Only bay pic I have to hand:
(http://i277.photobucket.com/albums/kk41/najiru/FC%20Rx7/P1010471.jpg)
If najiru has it done then it is possible, only thing I can think of would to be alter the manifold to bring the turbo further forward to get the clearence?
Najiro- 4in! Good stuff!
To be honest it looks like your turbo is in the same position as mine, almost identical, so that bodes well.
Depending on what I do and what I use from the various things I have, I might have to modify the manifold for T6 fitment anyhow, but yours shows its possible, and thats all I need to know :)
Dont suppose you have any pics that show the downpipe area at the back of the bay clearer do you? :)
Just been out and taken some but not easy to show clearly, tried to show the route best I could it only just fits through lol. HTH
(http://i277.photobucket.com/albums/kk41/najiru/FC%20Rx7/P1010499.jpg)
(http://i277.photobucket.com/albums/kk41/najiru/FC%20Rx7/P1010496.jpg)
(http://i277.photobucket.com/albums/kk41/najiru/FC%20Rx7/P1010501.jpg)
Superb, thats a great help, thanks a lot! :D :D :)
Looks like your wastegate position is very similar to mine too (mines an ERC tubular manifold allegedly, but bet ERC bought it from HKS or someone, lol) so that gives me good hope.
Your DP sits futher away from the inlet, but that may be as the FD manifold doesnt stick as far out, but TBH that seemed the least of my worries :D
Thanks again
its an RE manifold
T6 flange is definately excessive, we run a T6 on the 20b and its massive, if you are still gonna use it for drifting then you will struggle with lag with any T6 footprint.
it sounds like you want big power, if so i would go for an RE Engine if i were you.
naj: is that jons (888gtr?) old fc? else looks similar :)
if its not then i think jon had a 4" system on his time attack fc.
shame he\'s no on here any more but if you search then you should be able to find his build thread on here. else he\'s on fduk but im sure a few ppl on here would know about it.
It is indeed Liam, he now has my old fd :)
Quote from: najiru;703718It is indeed Liam, he now has my old fd :)
one of my fav fc\'s!! :)
Haha, cool thanks, though all credit to john of course :) Going to pick up where he left off and improve a few bits further though there really isn\'t so much needs doing.
Quote from: antnicuk;703716T6 flange is definately excessive, we run a T6 on the 20b and its massive, if you are still gonna use it for drifting then you will struggle with lag with any T6 footprint.
it sounds like you want big power, if so i would go for an RE Engine if i were you.
Seen the turbo I have have 1bar by under 4k on 13Bs, my cars got fook all worth worrying about till about 5k anyhow, no im not fussed.
Manifold flange is only a tiny bit of the equasion.
Not sure what route ill go anyhow, got loads of options kicking round here. As im lazy I prob wont use it anyhow just due to the extra fab work.
And my engine I have would be no restriction even at 500bhp+ so im not going for any other engine.
Regardless, this was purely about fitting a certain exhaust diameter in an FC bay, I really dont want any tuning advice. Unless you know much about diesel fuelling? Ive done a few things to my daily earlier, but im not sure what screws you turn to adjust the fueling...
fine by me, no tuning advice given then .......................
Quote from: StavFC;703755Seen the turbo I have have 1bar by under 4k on 13Bs, my cars got fook all worth worrying about till about 5k anyhow, no im not fussed.
Manifold flange is only a tiny bit of the equasion.
Not sure what route ill go anyhow, got loads of options kicking round here. As im lazy I prob wont use it anyhow just due to the extra fab work.
And my engine I have would be no restriction even at 500bhp+ so im not going for any other engine.
Regardless, this was purely about fitting a certain exhaust diameter in an FC bay, I really dont want any tuning advice. Unless you know much about diesel fuelling? Ive done a few things to my daily earlier, but im not sure what screws you turn to adjust the fueling...
you really are a door handle . you ask people on forum for info and advise. the good and very knowledable people offer there far superiour knowledge of EVERYTHING rotary related than you. and all you have the ability of doing is shunning them. i`ve not yet seen in any of your posts where you actually admit your wrong. i wish there was a block button so you didnt show up from my computer because you really pi$S me off. go back to chavy corsa`a. where you might have a bit of knowlege. ....
Quote from: antnicuk;703782fine by me, no tuning advice given then .......................
seriously mate. this bloke is a tool. dont waste your key board life typing giving him advise because he`s one of them people thats always been there and done it quicker...
WHY ASK FOR ADVISE THEN SLATE IT.. K n 0 &
Lol!
I simply asked about downpipe size. And I got the answer and it was appreciated, hence all the thankyous etc to the person who helped.
I didnt ask about tuning stuff, and didnt give anyone enough info to even HELP me about any tuning stuff even if I did ask.
Any advice given from the info I gave on anything other than downpipe size, even from the best tuner in the universe, wouldve been incredibly vague as best, totally wrong at worst, so couldnt and shouldnt be given.
I certainly didnt start giving people abuse like you have to me, I just wanted the info on what I asked, nothing else to confuse things for now.
So why these two posts trying to give me abuse?
Pathetic, but that sums up people giving it the biggun on the internet really.
Never owned a Corsa or anything similar either, so that comment is just as retarded as the others you made.
I hope that little outburst made you feel better about yourself though :)