Throttle issue on boosted RX8
 

I have a STS turbo setup on my RX8 I am still using all stock engine internals so I am only pushing 5lbs of boost in conjunction with a walbro 255lph fuel pump. At current the car is creating about 350 whp on pump gas however I keep having throttle issues either its opening too quickly or it sputters or something. I am wondering if the manual Throttle Body conversion would remedy this issue or not?

I am still looking for options/help with this issue it is making it difficult to track as cornering is random at best it either sputters or the throttle opens too quickly I am hoping to find out if I can get by with just the esmeril coil pack upgrade or just the manual throttle body conversion from rotary works.com or do I need both and if so what tps do I need for the TB it just says ford on their website? Any and all help would be greatly appreciated.

350 whp at 5 psi ... wow nice

You've not really provided enough information to for anyone to help you out.

What makes you think its the TB?
What you have described could be a number of things.

Do you have a data log of the sputter that we could look at?

I was thinking that was a lot for 5psi.

The main thing is at the current time the tuner I went to basically used the stock ECU to control the car I have tried the greddy emanage and also tried the haltech re the greddy apparently didn't have enough control-ability and the haltech re can only control 4 injectors (I have the High power) but the main thing that is the most aggravating is when you push on the accelerator it will choke out then open up and the way I drive a manual is I tap the throttle a few times as I release the clutch I don't just hold the gas pedal but as I am tapping it is almost as if the throttle is about a second behind my input and when I want to get on it it will either sputter out or will take about a second almost as if the throttle response is delayed I'm thinking the sputter is because I still have stock coils and almost 68k miles however I am using the plugs that said they were for turbo RX8s and I am also using nology hotwires plugwires I hope this can help with someone diagnosing without actually being able to see and hear what I mean. also I don't have any of the data logs I am sorry but maybe if I took a video of it I might could send that out if that would help.

A video with sound would be helpful

A lot of the turbo'd rx8's use the Cobb AP

You might want to consider changing your thread title to something a little more appropriate.

"Need Help" isn't exactly going to attract the attention of the people you'll want to help you diagnose your problem.

You'll need to PM a Moderator to change the Thread title.

Off the top of my head with the little information you've provided there is nothing I see here that would make me think the TB is bad (but it is possible I guess)

To Me it sounds like the car isn't tuned correctly.
However 350 whp with the stock coils could be an issue.

Which plugs are for the turbo RX8? You know that they don't make plugs for a turbo RX8.
I use a combination of RX8 plugs and RX7 plugs

It also helps if you separate sentences with periods or commas, as well as avoiding a wall of text.

MicroTech EFI :: Products

these are the plugs I bought and I am working on getting the video together and I was recently told the cobb was not for turbo applications (could be bad info but was just told that)

@ RX8 soldier, yeah my english teachers pretty well hated me lol but thank you.

so you get on the throttle and you hae sputtering/jolting hesitation? that sounds like coils to me.

do you have any cels/blinking cels or any way to data log whats occurring? who is the tuner and what did he do to tune it?

where are you?

currently it is giving me two CELs not sure which one is the blinking one, one is P0172 and the other is P0301, so bank one too rich and cyl 1 misfire. which is the main reason it lead me to believe coils, and unfortunately at this time I do not have the means to data log as the tuner ran an open source on the stock ECU not sure everything that occurred during the tuning process and I am currently located in eastern NC however will soon be moving to the dc/northern va area.

he meant to say 250 but had a brain fart .....

look if you're just going to bash don't comment please unless you have anything that might have something to do with my current throttle issue/sputtering issue I'd rather not see your comments and I saw the numbers on the dyno and have the printout thank you.

At 5psi a Renesis will make 250 whp TOPs - if you have the dyno post it . Otherwise I call a bit fat


:bsflag:

Stock injectors will also struggle at 350HP. Sounds like you are running very rich if the car is bogging. Best find a good tuning software and programmer.

Misfire's with a turbo setup is definitely not the best. Is it sputtering or detonating? Definitely I would recommend you take it easy on the car till this is figured out. Do you have a wide band Air Fuel gauge? if so whats is it saying before is sputters? If you don't have one get one. If you get into boost slowly do you experience the same condition? Were is your waste gate vacuum line coming from? What RPM's is this happening at? any chance it's around 6500rpm? If by any chance your leading plug is the one misfiring this is bad news. I dought your problem is linked to your TB.

May sound a little funny but my old low compression engine which was NA would sometimes sputter, after I started using pre-mix (250ml per tank of high quality Motual synthetic) it was smooth as silk. Not a bad thing to try it's easy and cheap... well relatively cheap adds an extra $5 per tank and cooks your cat.

If you've had detonation your engine is most likely cooked. Also Brettus is one of the experts here when it comes to turbo setup's and can be a great asset I would try to lay off him as he is very often right.

it is definitely sputtering thankfully however I am taking it easy I would love to find a tuner who only deals in RX8s and yes I do have a wide band hooked up and its rich as can be in low RPMs (below 4k) its all over the place between 21 to about 17 then at about 4500 plus the mixture evens out and starts to decline it goes from about 16 down to 11 (at 8000)
The waste gate with the is located in the rear of the car with the turbo with the vacuum line pulling from the brake booster like the installation manual suggests and if I drive like a normal person the car acts just fine and if I easily push into full throttle its fine it only does it when I go from cruise, cruise, cruise, 100%
and @ brettus I posted all of my pictures thus far to include my dyno sheet and going by the tuner he said his dyno is a bit off so he says to add about 12% !math time!
325.1 x 1.12 = 364.112 also it keeps up with my buddy's 300+awhp WRX just fine
not saying you're wrong in all cases but this one yes.

Jesus, what a clusterF#$k to read. How about you give us some info. 350WHP at 5psi? Yeah, in your dreams buddy.

1. How did the tuner tune it with the stock ECU? What do you mean using opensource? Harrison R&D?
2. What injectors are you running and where are they located?
3. What fuel pressure are you seeing?
4. Any AFR over 16 is dangerous to the motor in boost so the first thing you need to do is stop driving it hard.
5. Whacky AFR's can be a lot of things, including a jacked up motor. Have you had the engine compression tested? Do it, otherwise you might be chasing tuning issues when you have a handicapped engine.
6. How are you feeding oil to the engine? Who did the piping? This is a universal STS rear mount right?
7. How is your intake setup? Are you running the MAF sensor or a blow through setup?

Okay, just looked at your profile pics and it is a blow through setup. I'm not even sure how that could be tuned properly without a stand alone or Cobb. Heck its tough to do it even with the proper info.

I wasn't able to be present for most of the tuning process as at the time this was my only car and Force-fed performance was the only place that would touch an RX8 so as far as what program he was running I am unsure I know he said it was just like the program he uses for their STIs and EVOs however.
so far stock injectors but the tuner gave me some out of his evo he said they would fit I haven't tried yet but he said he ran 500hp out of his evo on the injectors so they will be more than enough for my needs
Fuel pressure not sure I know it does have a walbro 255lph in it though
and yes it is the "universal" STS so basically all custom piping it was done by the guys at extreme motors however I am quite unhappy with the piping and want it pretty well redone I just need more cash
and I guess my biggest question right now is how to test to make sure I didn't toast the engine already I know it feels alot warmer after running it even just going down the road for groceries but the gauge tells me no different

also anyone willing you can pm me and I will give you my cell and it will probably make the process of asking questions both ways a bit easier however if you're looking to troll please don't that's all I ask.

Man, depending on how the kit was put together it could be several different things. Getting a kit designed for an RX-8 to run properly is tough enough, a universal rear mount blow through setup is a whole other ballgame. The best advice I have is to find a reputable shop to get this sorted and then get it tuned by someone familiar with the RX-8.

yeah thats why I just bought a diesel truck so I can tow my baby if need be the guys at force fed were very knowledgeable but mainly on the ever popular STI and EVO not quite the same ballgame when it comes to an RX I know.
but for someone moving to the northern VA/ greater DC area do you have any suggestions on shops to take it to like I said I will need the "cat-back" area pretty well redone ensure the vacuum lines are good and hopefully tell me why it feels so much hotter under the hood.
and any suggestions on EMS I have a greddy emanage but that didn't work nor did a haltech RE I sold the RE back already but I was wondering about the Haltech platinum sport 1000

Umm, as far as I know correct me if I'm wrong it's air fuel ratio, so if your seeing 21 parts of air per part of fuel you are the opposite from rich, you are leaner then lean, at the point of pitting the inside of the chamber! It shouldn't go over 12 some argue up to 13 but never the numbers your seeing. Please correct me if I'm reading your post wrong, but if this is what I think it is you definitely pooched the engine, and your tuning is completely wrong.

This is just a classic example of improper planning an execution. You really need to read up on boosting an RX-8 to get educated so that you can make informed decisions on how you are going to get this taken care of. And yes, hitting AFR's of 15's or above in boost is pretty much going to guarantee a ping. Your targets should be in the 11's and you should be at or near stoich at cruise.