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Originally Posted by j9fd3s
(Post 11300061)
there are a few ways to run 10psi on a T2....
i think the #1 thing is an FD fuel pump. if you do the maths, the stock T2 pump will only move 550ccx4 of fuel, its exactly the same size as the injectors, and that is if its in 100% perfect condition. so the best thing to do is upgrade to the FD pump which flows more. its also a great idea to replace both fuel filters, there is one in tank. second on the list is making sure the car runs right in the first place. i've tried to do this other ways, but on a T2 its just easier to pull the intake and check everything, literally. vacuum leaks are bad, the vacuum hoses need to be hooked to the right place. i find the vacuum diagram isn't good enough, so i actually pull each end of a hose and make sure it is right. etc etc. third you need some kind of exhaust, the precat should be replaced with a downpipe at least. i like the Rb turbo back system/revII, although in CA we buy two more flanges and put a cat in the middle, it will pass smog like this. 4th, i like the S5 turbo better than the S4, response is better, and boost creep is basically 1-2psi which is fine. i've found the S4 turbo can creep like 6-7psi, and this means you either need to have the car setup for it, or restrict it somehow. 5th, electronics. this is an important step, as you need to get rid of the overboost fuel cut, and then either add more duty cycle OR larger injectors. i have found that if you can increase the injector duty, with an FD fuel pump, there is enough fuel for 12psi with the stock injectors. if you cannot increase injector duty, then larger injectors are needed. these days the Rtek 2.xx is probably the best way, you get the FCD, you can adjust fuel and timing, and there is no add on boxes, or wiring splices, plus you are tweaking the stock maps, instead of starting from scratch like a haltech i always ran F-cons, they work great as long as you don't go nuts. I may try finding an s5 turbo but I'll already have an s4 but I'll have to get it rebuilt or get one in good working condition, and I know s5 are harder to come by and more pricey. Car will be running stock boost when I first get her going, but I do want to set it up so it can run higher boost later on without having to remove too much stuff (mainly the turbo: I'll port the waste gate if that will eliminate all my boost creep and allow me to maintain stock boost as well as bring it up without getting boost creep) rotary>pistons |
Originally Posted by wthdidusay82
(Post 11300071)
What is needed to stop the boost creep on an s4 turbo? I really can't afford a rtek 2.0 I'll probably be getting a stock ecu or a rtek 1.5 or 1.7
Car will be running stock boost when I first get her going, but I do want to set it up so it can run higher boost later on without having to remove too much stuff (mainly the turbo: I'll port the waste gate if that will eliminate all my boost creep and allow me to maintain stock boost as well as bring it up without getting boost creep) rotary>pistons Restricting the intake/exhaust is a good way to prevent boost creep, besides porting the wastegate. |
Originally Posted by K-Tune
(Post 11300073)
Restricting the intake/exhaust is a good way to prevent boost creep. rotary>pistons |
Porting the wastegate definitely helps, but doesn't always do the trick. A hi-flow cat helps as well, and keeps you legal as well. Anything to restrict flow.
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Port the wastegate out to >1", weld a valve as the new 'flapper'. Plain washers will deteriorate and will end up looking like a snowflake.
It's easier to identify a component turbo/intercooler/injectors that you don't want to replace and do everthing needed to support that component. You can't do the bare minimum but be ready for more later. I appreciate that you are doing things on a budget, but cutting the wrong corners is how rotaries get such a bad reputation outside this forum. And in the v8 section. |
I'm only planning on running stock boost when its first running, I just figured it'd be a good idea to port my waste gate as well as have an idea of what else will need to be done in the future.
rotary>pistons |
Originally Posted by wthdidusay82
(Post 11300071)
What is needed to stop the boost creep on an s4 turbo? I really can't afford a rtek 2.0 I'll probably be getting a stock ecu or a rtek 1.5 or 1.7
I may try finding an s5 turbo but I'll already have an s4 but I'll have to get it rebuilt or get one in good working condition, and I know s5 are harder to come by and more pricey. Car will be running stock boost when I first get her going, but I do want to set it up so it can run higher boost later on without having to remove too much stuff (mainly the turbo: I'll port the waste gate if that will eliminate all my boost creep and allow me to maintain stock boost as well as bring it up without getting boost creep) rotary>pistons second on my car i had enough fuel so that boost spikes were fine, so i never did anything. everyone else tries to run the stock ecu/fuel system and port the wastegate so they can run less boost. the S5 turbo controls boost way better so you have choices |
Well maybe I'll try to get an s5 turbo if its a direct bolt on, I just figured I'd use s4 since I already have one, I'll have to check the cars exhaust to see if its stock...I'd just rather use the s4 because it'll cost me less money.
From what I'm hearing there's really no reason to keep the s4 turbo if you have the oppurtunity to upgrade it (which I will since I'm rebuilding the engine) rotary>pistons |
s5 turbo is a direct bolt on, IF you have the s5 manifold as well. s5 turbo and s4 manifold do not match up.
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tru but in all honesty i would personally run what u have and make sure that u keep the boost at a stock level until you have the resources to run what u want to run. i built my s4 conservative so that i can have fun but also have it as my daily driver. now if you already have a daily driver i would take the time to build it right so that way u can do what u want to do to it. just my 2 cents. my fc was a budget build some wheelin and dealin with the guys here on the forum. im pushin 14psi on rtek 2.1 550cc prim 820cc sec 3 inch exhaust stainless steel tubular mani. apexi avc-r boost cont garett t67. we guesstimate anywhere from 300 to 350ish also forgot aeromotive 340lph pump and a few other things.
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Yea I want to keep it close to stock, I'm very paranoid so I always make sure about everything before I do it.
I'd bring it up 1 psi at a time, slowly bringing it up. I'm in no hurry but I do want to eventually get it close to 10 psi but that's a long term goal, short term would be 6.5-7.5 psi rotary>pistons |
its very possible to do that but from experience ur gonna want to boost her. they love it. also i run water injection aswell which i think helps alot with knock and so forth. u seem to have ur head on right and kno what u want. luckily this forum helps out a lot with questions anyone has.
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isn't the comp. wheel the same on both turbos? They move the same air. Your only upgrading is the wastegate opening size. enlarging the S4doesn't sound that hard to do.
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there are many write up on here on how to upgrade the opening to the wastegate. many have been successful with it.
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Its really easy to port the wastegate on an s4 I did it inside an hour after I got the turbo apart.
One of the better ways to restrict boost creep I've found is to keep the stock airbox and intake piping. It won't eliminate it totally if you have a free flowing exhaust but it really helps. You will need an FCD. I think I have one for an S4 somewhere. |
What's the range of boost that can be run with a ported wastegate? At first I'm going to run it stock but I do want to run more boost eventually.
rotary>pistons |
With a good boost controller you could run 10-12psi. I had a poor quality boost controller and it would not hold the boost up top all the time.
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Originally Posted by Alak
(Post 11300577)
With a good boost controller you could run 10-12psi. I had a poor quality boost controller and it would not hold the boost up top all the time.
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Originally Posted by RotaryRocket88
(Post 11299051)
The simplest "safe" means of running a stock turbo up to its limit of ~12 psi would be an rtek 1.7, 720cc secondaries and an FD fuel pump. This can be done for $3-400.
Would a FD pump support a Rtek 1.8 (4x 720cc)? |
Originally Posted by MrGoodnight
(Post 11392932)
I wanted to bump this up with a related question.
Would a FD pump support a Rtek 1.8 (4x 720cc)? 720 secondaries is enough for a stock turbo at 12 psi. |
Originally Posted by RXSpeed16
(Post 11392940)
Not if they're being maxed out. FD pump is rated for about 300hp. According to the Rotary Performance website's calculator, 4x 720's should be capable of 350. 720 secondaries is enough for a stock turbo at 12 psi. Also I was thinking of a Bnr stage 1 at 10-12 pounds rather than the stock turbo. |
Most im going to run 10 psi since I've read about intake temps with stock tmic get hotter than they should be at 12 psi.
I don't like the idea of hot intake temps, seems like a bad idea. Rotary >Pistons |
do you have a wideband a/f gauge? get that and a boost gauge as your first mods, then you will know whats going on in the engine
if the exhaust and or intake is not completely stock, then you will get boost creep, you definitely want to port the waste gate as big as u can, and if your exhaust is really free flowing you still may run into some creep. I don't really see any point buying the rtek 1.5 if your going to run it at stock boost levels keep the stock ecu, that way if your boost does creep youll hit fuel cut and know to stop instead of keep going and risk running lean and blowing up. ( it can be argued hitting fuel cut in it self is pretty bad, but I think its a hey stop what your doing warning, vs wrapping it out on a cold day in 4th gear and blowing it up) if you want to go over stock boost on a stock ported motor, and stock turbocharger at all id at least just get the 1.7, walbro, and the 720 injectors. it adds more headroom for if your boost does go somewhat higher than u planned. also get all of your injectors cleaned/flow tested, and change your fuel filter. |
one benefit to a s4 turbo, with a loud exhaust is If twin scroll is hooked up and working, with it closed below 2800 the exhaust is noticeably quieter.
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The car doesn't have an s4 Turbo I'm upgrading to s5, car does have a full exhaust, stock intake/airbox, stock tmic, blitz bov, and I do have a fuel cut defender.
I will run stock 550cc primaries and 680cc 1st gen gsl-se secondaries (flow same as 720cc on 2nd gens from increased fuel pressure), fuel pump and ecu will be stock until I can afford to upgrade. I do plan on porting the wastegate, do I have to take apart the turbo to do it? I plan on getting a boost gauge for when I first get it running and possibly a manual boost controller (if peak boost is really low like 6 psi), I'll later get a wideband. Rotary >Pistons |
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