hi guys, my rex has been running a td06 with a 20g exhaust housing and serious boost issues.
the car was mapped to 0.5bar and running 302.4bhp, but anything above 0.5 and on planting your foot down the car would just jerk and jolt.
reworx put this down to the housing being to small to exhaust the gasses quick enough, and suggested getting a 25g housing, but these appear to be rarer than he preverbial, and as i\'ve just cooked my rex, and found what i think is substantial play in the turbo shaft, i want to replace it, but what would you guys recommend going for?
col
depends what power you want and what your going to use it for ie Street/Trak/Drag im sure plenty of people will give you lots of options but you need to decide what use you want it for before you can make an educated decision
well ideally i want to stay around the 400 mark, but also have it as an every day turbo, that could also be put to good use on the track...
col
I would suggest a GT35 but somebody with more knowledge will no doubt be along soon to advise you
http://www.rx7store.net/product_p/gt35r%20kit.htm (http://www.rx7store.net/product_p/gt35r%20kit.htm)
i want that :D
£1500
http://www.rx7store.net/Garrett_GT35R_Turbo_p/garrett%20gt3582rt4.htm (http://www.rx7store.net/Garrett_GT35R_Turbo_p/garrett%20gt3582rt4.htm)
or £780 for u ^_^
people have been making good noises about Holset turbos (HX35 seems to be the favourite). they\'re a British company as well (owned by Cummins) so should be a bit less expensive than the competition.
that\'s not from personal experience, just from lots of forum lurking :)
Bringing this back from the dead like Jesus rather than starting a new one, the HX35 has been mentioned...
Has anyone ACTUALLY TRIED a HX35 on a 13B? They are T3 flange which is not ideal, but messed about with one even on a 5litre V8 and it didnt choke it so the turbine clearly flows bloody well, and compressor wise its as good as a GT35 (proven 600bhp+ on counltess engines, seen 450+ on stock 2litres at under 1.5bar).
I happen to have an almost unlimited supply of HX35s, and my manifold needs to come off as its blowing, so no harm welding a T3 flange on, so its tempting.
Only want 400-450 at the fly really, so not exactly pushing the thing.
PS- On the original post... How on earth would the exhaust housing make the car jerk n jolt?! A hugely choking turbine really doesnt cause that effect?
Quote from: StavFC;637375PS- On the original post... How on earth would the exhaust housing make the car jerk n jolt?! A hugely choking turbine really doesnt cause that effect?
Seeing as you are a Rotary expert what would it cause?
I guess Reworx who are rotary tuners and have produced countless 9 and 10 second cars dont know what they are talking about ?? :2Rolleyes hmmmmm
I had to go bigger turbo with the bigger exhaust housing as my porting caused the engine to choke at high boost, causing a stumbing/jerking effect that I felt on the last runs with my old turbo
Im not a rotary expert and freely said on here I dont know them well at all, but I have experience of the fundamentals of turbocharged engine tuning, unlike most it seemed by that pathetic torque/boost argument the other week, lol.
My point is im VERY surprised choking through restriction cause jerking and jolting though (unless it was ANOTHER problem caused by the choking, like weak ignition issues), make the car flat as a fart, even cause such high backpressure it dets and hurts things, but surprised it makes it jerk and jolt on a rotary. Ive seen that once or twice on piston engines when choked, but that was only as it was causing valve float and missfiring.
Rather than rolleyes and sarcasm, why dont someone who KNOWS (do you? or just replying to argue?) explain why this happens on a rotary when restricted, as im sure we would all like to learn more about the unique issues on a rotary like this seems to be...
Or even, someone just answer my HX35 question rather than argue about something else they dont know about.
Well you entered an argument with your "PS" comment, disclaminig that a small exhaust housing would not give those symptoms and Reworx gave an incorrect diagnoses
yes I do KNOW read my last line in my last post regarding my own experiance with a choking rear housing, too small a housing would stop the exhaust gases to escape correctly from the exhaust port causing the gasses to be carried over to the next inlet charge. SIMPLES lol
Buy mine, is perfect for you
http://www.mazdarotaryclub.com/forums/showthread.php?t=59332
Quote from: BlitzBoy;637391yes I do KNOW read my last line in my last post regarding my own experiance with a choking rear housing, too small a housing would stop the exhaust gases to escape correctly from the exhaust port causing the gasses to be carried over to the next inlet charge. SIMPLES lol
Its not "simples". Exhaust gasses not all escaping is backpressure/restriction/choking, what happens on every engine, rotrary or not, simple engine fundamentals.
But it doesnt suddenly (ie go from fine to jolting like it has a missfire, without having noticable restriction issues beforehand) cause juddering, jerking, jolting
unless it missfires too due to valve float, detonation, weak ignition, etc. Flat as a fart yes, but not drive like its fooked.
So why then, if its 100% just a too small turbine and nothing else, and you KNOW, why does it act differently on a rotary, as I dont know?
Thats what id like to learn :Thumbs-up
Quote from: StavFC;637399But it doesnt suddenly (ie go from fine to jolting like it has a missfire, without having noticable restriction issues beforehand) cause juddering, jerking, jolting unless it missfires too due to valve float, detonation, weak ignition, etc. Flat as a fart yes, but not drive like its fooked.
If you read his first post correctly, he states its fine up to 0.5 BAR and it has been, its when he tries to increase boost he gets the problems. therefore more fuel and air are going in, but the resultant bigger faster exhaust gasses (Rotaries produce far higher EGTS then Piston engines) cant escape due to the exhaust housing being too small, causing it to be ingested in the next combustion cycle causing the mixture to be fooked hence the symptoms Reworx diagnosed
Quote from: StavFC;637399But it doesnt suddenly (ie go from fine to jolting like it has a missfire, without having noticable restriction issues beforehand) cause juddering, jerking, jolting unless it missfires too due to valve float, detonation, weak ignition, etc. Flat as a fart yes, but not drive like its fooked.
wouldn\'t it misfire though? given that a w4nkel\'s combustion chamber is long and thin if there is a load of exhaust still in there as the rotor comes round for the inlet \'stroke\', as Blitz said due to it not being able to escape a restrictive turbine, then surely this could seriously hamper combustion? after all, our engines have leading and trailing plugs to promote a healthy flame becuase of the awkward shape of the combustion chamber.
Blitzboy- I dead read it, and thats my point. Happy as larry till 0.5bar then missfiring STRAIGHT away above it seems odd for a simple ristriction and no other issues, not feeling flat as a fat before that?
Jackaleks- THAT is a relevant reply, thankyou :) It will hamper it for sure, restrictions a fact of any engine, and maybe rotaries suffer this more than others due to the relativley poor combustion chamber shape as you say :)
Im still fairly amazed it went from fine at 0.5 to SO choked up with exhaust gas it actually missfired (without a weak ignition or incorrect mapping) anything above that, as on piston engines you will have a hell of a long way of choked up, flat as a fart, rubbishness that would warn you its pointless to push further, before the inlet side of things was so polluted by exhaust gas it wouldnt even fire.
Be interesting to know for sure rather than take someones word for it, as it seems odd being so sudden, but hey. :)
Unless others with actual first hand experience (ie wasnt just told by a tuner it was or it wasnt that) can say either way, I guess we will never know.
Quote from: jackaleks;637407wouldn\'t it misfire though? given that a w4nkel\'s combustion chamber is long and thin...
this is pure speculation by the way! just in case anyone thinks i actually know what i\'m talking about :rolleyes:
Quote from: jackaleks;637468this is pure speculation by the way! just in case anyone thinks i actually know what i\'m talking about :rolleyes:
dont worry dude it made sense , shame Stav cant admit he does not though, but then again who can take Stav seriously after he posted pics of his willy on a public forum (Driftworks). I wonder if Redline magazine knew he did that? :spank
(http://spdfrek.smugmug.com/photos/212032750_stq8S-L.jpg)
I have had a chat with a few people about turbos for about 400-500bhp for a rotary, I have the same kind of goal as you, im getting a Garrett GT4088 :)
gt4088. thats deffo for the higher end of the power spectrum ie nearer 500hp.. will be more laggy than the 35 . good turbo though.
Quote from: StavFC;637413Be interesting to know for sure rather than take someones word for it, as it seems odd being so sudden, but hey. :)
Unless others with actual first hand experience (ie wasnt just told by a tuner it was or it wasnt that) can say either way, I guess we will never know.
have you not noticed the post count of the person your saying dont know rotaries LMAO
So post count, age, and calling yourself a tuner makes you an expert? Lol. Ok, if thats the case, im Jesus, as I say so, but I dont have to provide any proof, as I said so.
Im asking for reasons, proof, etc, to gain knowlege. Some might be happy living in your little bubble of knowlege, but id like to learn things. :)
PS- Blitzboy, YHPM on RX7 Club, dont think I can PM on here? :confused:
Quote from: m1tch;637479(http://spdfrek.smugmug.com/photos/212032750_stq8S-L.jpg)
I like :Laugh
Quote from: StavFC;637528So post count, age, and calling yourself a tuner makes you an expert? Lol. Ok, if thats the case, im Jesus, as I say so, but I dont have to provide any proof, as I said so.
Im asking for reasons, proof, etc, to gain knowlege. Some might be happy living in your little bubble of knowlege, but id like to learn things. :)
PS- Blitzboy, YHPM on RX7 Club, dont think I can PM on here? :confused:
what the F are you on about being in a bubble. he has given you proof . his own car which is one of the quickest in the uk for starters, he had this problem with same syptoms and solved it by fitting bigger exhaust housing.. think that answers this thread:eek:
Quote from: StavFC;637413Blitzboy- I dead read it, and thats my point. Happy as larry till 0.5bar then missfiring STRAIGHT away above it seems odd for a simple ristriction and no other issues, not feeling flat as a fat before that?
I\'ve not seen mention of what the boost was raised to above .5bar, so we cannot assume that problems happened at .501bar... try posting with a little more thoughtfulness :wave
I\'m sure what you meant to say was "At what point above 0.5bar did the problems begin to surface?"
As we know an increase in pressure will exponetially increase the amount of heat produced, so it is feasible that issues that were barely noticable, (or not present) at 0.5 bar will begin to show quite quickly as the pressure mounts. If there is an air stall in the manifold due to back pressure then this will only serve to super heat the immeadiate area, causing further gaseous expansion and hilarity will ensue... :flamed
A few more smilies and a little less of the condescending approach will work wonders for you here. :Thumbs-up
Play nice, toys taken away if not etc.
Regards,
Brett
Quote from: Brett;637563A few more smilies and a little less of the condescending approach will work wonders for you here. :Thumbs-up
So Blitzboy replying with a rolleyes to my valid technical question, then despite me saying im no expert and saying im asking as id like to learn these rotary-piston engines differences, he doesnt explain, just talks down to me, then just starts on the personal attacks (here and on RX7Club), is totally fine yeah? :confused:
Thats quite an odd set of rules we have here :) One rule for one, one for the other :)
Quote from: StavFC;637591So Blitzboy replying with a rolleyes to my valid technical question, then despite me saying im no expert and saying im asking as id like to learn these rotary-piston engines differences, he doesnt explain, just talks down to me, then just starts on the personal attacks (here and on RX7Club), is totally fine yeah? :confused:
Thats quite an odd set of rules we have here :) One rule for one, one for the other :)
I think it\'s a simple case of you get back what you give out. You claim you want to learn, but when you\'re told something by some of the most repsected authorities on rotaries in the land, you basically say "you\'re wrong. I don\'t know why, but you are" and then get all hostile about it. Sometimes a bit of humility gets you more consideration than fronting people up and telling them they\'re talking rubbish....
Stav It was your original PS comment dude, I replied to it then you dismissed my reply
Quote from: StavFC;637528So post count, age, and calling yourself a tuner makes you an expert?
:
that is the sort of post that is getting peoples backs up..
someone who has been studying how rotarys work for years. tunes many peoples cars on here. has posted countless number of useful advise to others.. imo makes them a very good canditate for a rotary expert.
you MIGHT(in capital letters) have alot of knowledge of the piston engine and the prinsipals of turbo chargers but it aint all transferable to the rotary. listen and learn dude.
take chill pill, dont be patronising and condisending to people offering genuine rotary advise and keep your willy in your panties please. :Hammer
The reply to the PS wasnt an explanation it was a "How dare you question the tuners explanation" and a repeat of what was said by the OP.
I was interested in the tech reason why this happens on a rotary, as it certainly doesnt happen the same on a piston engine in the same situation (ie massive turbine restriction polluting the inlet cycle with exhaust gas), but ive never got a reason for the drastic change in result from piston to rotary.
I dont mind not getting a reply, as if nobody here knows for sure you cant expect one, but being slated/abused for even asking is out of order I think, and then being the one who gets \'told off\' for it is just bizzare, lol.
Without the \'how dare you question anyone\' and abuse this could make a fairly interesting technical discussion, OR if anyone could explain, it could just teach the rest of us something.
Quote from: skybusr34;637611listen and learn dude
How can I listen when I ask for a detailed explanation why something happens and nobody gives anything but abuse?
Believing stuff "because they say so" without any proof is the main cause of problems in the world. Ill leave that to the religious lunatics, I want to make my own deicsions on whats right or wrong, not be someone who blindly follows their leader.
I dont say they wrong unless I know they wrong, but unless i know they right I want to know why they say they are right before I take it as gospel.
im no expert. but
if his car has been ported there could be exhaust and intake overlap. and if there is alot of exhaust back pressure it will push into the intake stroke as its lower in pressure. then on the compression stoke oxygen level is low. causing low explosion. hense juddering ..
please tell me if thats complete poop peeps and im talking out of my bottom :-)
I have a .7 ar with a .81 hotside. Even though after one drag the whole sys glows near yellow (its that restrictive) i get no misfire. Up to 8000 rpm. I wonder why yours does and mine doesnt.
Quote from: StavFC;637612but ive never got a reason for the drastic change in result from piston to rotary.
I dont mind not getting a reply, as if nobody here knows for sure you cant expect one.
I gave you the reason but you dismissed it as not being Simples
Quote from: StavFC;637612How can I listen when I ask for a detailed explanation why something happens and nobody gives anything but abuse?
.
Do you never stop to wonder why just about every thread you ever post on on any forum ends up like this? What\'s the one single continuous factor across all those threads? Oh....it\'s you!
Why would that be, do you think? Either there\'s a conspiracy of concerted ignorance and malevolent belittlement aimed purely at a) keeping you ignorant of the answers to your "tuning" questions and b) making you look a c0ck....or you simply have a God-given gift for coming across as an arrogant, insulting, opinionated know-it-all who asks pointless questions just so they can argue with helpful souls who try to answer them. Why don\'t you ask yourself which is the most likely of those two scenarios?
No-one comes on here to try and make you look stupid or to misinform you with deliberately misleading information, frankly no-one finds you interesting enough to bother with beyond the fact that you\'re a standing joke across the entire performance car-related internet community and it\'s funny to see how you react when your buttons are pressed. Once the initial entertainment of that has gone stale, you\'re just left looking a very bitter and inadequate person with little to redeem you beyond the most hillarious and aggressive inferiority/persecution complex ever seen. Please take your internet warrior drivel somewhere else where it\'s just possible you aren\'t already infamous and you may actually be taken seriously, no-one here wants to play your schoolyard games
Quote from: Nik da Greek;637630Do you never stop to wonder why just about every thread you ever post on on any forum ends up like this? What\'s the one single continuous factor across all those threads? Oh....it\'s you!
Why would that be, do you think? Either there\'s a conspiracy of concerted ignorance and malevolent belittlement aimed purely at a) keeping you ignorant of the answers to your "tuning" questions and b) making you look a c0ck....or you simply have a God-given gift for coming across as an arrogant, insulting, opinionated know-it-all who asks pointless questions just so they can argue with helpful souls who try to answer them. Why don\'t you ask yourself which is the most likely of those two scenarios?
No-one comes on here to try and make you look stupid or to misinform you with deliberately misleading information, frankly no-one finds you interesting enough to bother with beyond the fact that you\'re a standing joke across the entire performance car-related internet community and it\'s funny to see how you react when your buttons are pressed. Once the initial entertainment of that has gone stale, you\'re just left looking a very bitter and inadequate person with little to redeem you beyond the most hillarious and aggressive inferiority/persecution complex ever seen. Please take your internet warrior drivel somewhere else where it\'s just possible you aren\'t already infamous and you may actually be taken seriously, no-one here wants to play your schoolyard games
ROTFL what an outstanding response. . cant add to that one. nice one:cheers
Nik- You mentioning forum warrior about me, with a reply like that, is nothing short of hillarious. But crack on, I thought this thread was going back to being interesting but your determined to keep it on the \'lets try and put him down\' side of things. Go for gold, must make you feel better, especially with the other forum members cheering you on like above, thats why you do it right?
Quote from: skybusr34;637616im no expert. but
if his car has been ported there could be exhaust and intake overlap. and if there is alot of exhaust back pressure it will push into the intake stroke as its lower in pressure. then on the compression stoke oxygen level is low. causing low explosion. hense juddering ..
please tell me if thats complete poop peeps and im talking out of my bottom :-)
Thats not poop, what you say does happen :yes Thats the fact of backpressure and restriction, works the same in piston engines, more pronounced when you have lots of overlap, and part of the reason all engines dont magically make unlimited power.
But what they dont do is hugely judder and buck and go crazy when this happens, they behave as I said earlier.
Maybe rotarys are different, I dont know why they would behave like that, and nobody has been able to explain why, but id sure like to know, could save people some expensive mistakes.
Quote from: BlitzBoy;637625I gave you the reason but you dismissed it as not being Simples
Because thats not simples, what you explained is just backpressure that all combustion engines suffer. I was interested to know why, technically, rotaries seem to go from making power to bucking and juddering like they missfiring, totally different to how a piston engines behave in the same situation.
Quote from: DR SCHNITZEL;637620IEven though after one drag the whole sys glows near yellow (its that restrictive) i get no misfire. Up to 8000 rpm. I wonder why yours does and mine doesnt.
Great info :Thumbsup! Well thats exactly what I expected to happen, purely as thats how every other (ie piston) engine ive ever seen behaves when hugely restricted. Power drops off, things get hot, detonation and even engine fail can happen, but missfire? This is the first time ive ever seen that without valve float or a fuelling/ignition problem. And id like to learn why this rotary phenominon exists, as its pretty bloody important when tuning id say!
Never criticize anyone\'s ideas, get them to show you the data. Until they have real data, they are just another guy with an opinion
lol Nik you are a legend
I explained the exhaust gases get ingested into the intake cycle causing the misfire, the 20g housing is tiny for a rotary, a TO4r housing (Dr Snitzels turbo) is much bigger then the 20g it will give different results
Exhaust gasses get ingested in to the intake cycle to some extent on all setups, the reply to that point as been discussed countless times on this thread already, so saying that once again doesnt explain anything without explaining why the missfire happens on rotaries and not piston engines, as thats what im wondering.
A simple "I dont know" will do, as ive no ....ing idea either, but would love to know.
You said your old turbo did it too Mark, to the 20G housing point is moot.
Plenty of 20Gs seem to have got 350@wheels elsewhere at 1bar or more. Not 0.5 and 300bhp and it missfiring due to a \'small housing\', which makes me wonder even more.
Quote from: StavFC;637649Plenty of 20Gs seem to have got 350@wheels elsewhere at 1bar or more. Not 0.5 and 300bhp and it missfiring due to a \'small housing\', which makes me wonder even more.
I\'m assuming that is on a piston engine though (or in the US where they seem to produce outrageous BHP claims!)
As has already been said, rotaries produce massively higher EGTs than piston engines so the level of increased horsepower from a turbo is lower. The GT4088 on mine is good for 800bhp on a piston block, but the best I\'m likely to see is round 450bhp - 500bhp (and that is on a heavily bridge ported engine!).
I think Blitzboy has actually answered your question several times, he has said that exhaust gases contaminating the intake mixture cause the missfire, now bearing in mind the fact the tose exhaust gases will be VERY hot, there is a chance of missfire or even DET or failing that the O2 level may be too low to allow proper ignition/combustion at all.
Bearing in mind the differences between a piston and a rotary combustion cycle, I think the problem would be less apparent in a piston block as you would be unlikely to see the same volume of exhaust gas pushed back into the combustion chamber.
Now I am not a tuner, I only know what I have been taught, experienced for myself and witnessed in the years I\'ve been messing with rotaries, but the above would seem to be a logical explanation :WaveBye
Unless these setups are all running identical ports it\'s difficult to compare. Also, the very nature of the rotary dictates that symptoms will show themselves differently.
HX35\'s are pretty good and can be had for about £450 NEW
However StavFC,
I just fitted one to a 2JZ in a chaser with a friend and it had a T4 Flange not a T3 like you said ????? Possibly a different exhaust housing to the ones you have ?
As for the whole missfire thing above .5 bar on a 20g housing.... Like has been said it re ingests the exhaust gasses duee to not being able to fire them out fast enough.
Due to the fact Rotarys run seriously rich compared to a piston engine this means it does still actually ingest some unburnt fuel and all the crap of the day along with fresh fuel which completely screws up the mixture, therefore causing your misfire and bag of sh**e running conditions.
Its the same with my last FD, I had it all set up for 1 bar on the twins with good exhaust etc and it ran perfectly.
I fitted an exhaust bung for noise reasons in my neighbourhood due to complaints and the car wouldnt boost above 0.6 bar It would judder and misfire and splutter and jerk and pop and bang etc etc along with completely fouling the plugs too.
this was due to the increase in back pressure (read restriction like a smaller exh housing on a turbo) which was "choking" the engine.
So in short the reason it misfires is down to the poor mixture caused by the choking caused by teh exhaust housing being too small on the turbo. However thats kinda what Blitzy has already said and it does answer your question fully so Im unsure why you keep asking someone to explain it further ?
Unless of course you like typing and causing trouble like a :Typing warrior LOL :Thumbsup!
Quote from: StavFC;637649Plenty of 20Gs seem to have got 350@wheels elsewhere at 1bar or more. Not 0.5 and 300bhp and it missfiring due to a \'small housing\', which makes me wonder even more.
thats depends on the porting
ive seen t88\'s start backing up on the dyno at 450whp but prev made 500+ whp on the same motor with smaller ports
going back on track with the thread before i get told im wrong/bottled in the face or mounted
i think a to4r/gt35 with 1.0 rear t4 will be ideal
we had one running 475fly with no problems (to4r)
colum
The guy who owned the car before me had it mapped at Re:worx,
it was mapped at 0.5bar and made 304.2 bhp, on standard ports and standard injectors. they were only able to partially map it though from what he\'s told me
He said Re:worx put this down to the turbo housing (20g) being too small to dispell the exhaust gasses quick enough, this would create a head of pressure in the manifold, (even if only for a miniscule amount of time) so as the next exhaust "stroke" came around it was trying to force compressed exhaust gasses into a space they physically couldn\'t go into, hence slowing the rotors down and causing the juddering effect.
this is just what was said by the guy who i brought the car from, if re:worx or any other tuners would like to add their input we could put a nice little full stop after this.
col
Makes sense that does :) :D
Dont worry , Im sure Stav will argue with Cols explaination lol
i doubt youll ever find reworx on here mate
alot of other things also can contribute to the same problem, exhaust being too small/retrictive and even the flow characteristics of an intercooler believe it or not
hope this helps (im not here for an arguement or to be proved wrong in some im better than you/my willy\'s bigger than yours etc etc contest, just sharing experience)
colum