My car has a freshly done rebuild. I have a t 70 turbo, with 550 primary and 720 sec. My problem is that the car will build boost beautifuly, but as soon as I get to almost 10psi it sputters and doesnt move untill I let go of the acc. It happens every single time. First gear it only hits 5psi, second hits five then when the actual power pull begins and it shoots off it gets to abbout 8 or 9psi and then it sputters all over the place. I was thinking that it could be my ignition, like I need to get a cdi box, msd or jacobs or something along the lines. Could that be the problem or could it be something else..???

 

What have you got in the way of engine management? What's the specs on the turbo (a/r, etc). From the pictures that's a bad spot for your intake, it's right behind the radiator, can you imagine the heat that things going to suck in? How is it tuned, what A/f ratio and so forth?

 

As for management I have the stock ecu, Im still waiting for the haltec. Im not really worried about the heat, charge pipe from the turbo to the IC gets pretty damn hot, but if you touch the intake side, its as if the car was never turned on.
Anyways that the only place I have space to put it, my turbo sits too forward...
Not tuned no afr's yet.

 

Ok, I'm guessing you're using an S-AFC and a FCD for the moment? It could be a couple of things, simply untuned could be the cause of it not spooling consitantly, or it could be detonation that's causing the bog from too much air and not enough fuel/management. It's also very possible that the hotside is just too large for the engine to spool, that's why the specifics would be nice.

 

you are running that setup on stock ecu? You should pray it wont go over 10lbs. Also with that turbo 550/720 combo will not be enuff.

 

Sounds like fuel cut to me? Do you have a FCD?

 

Exactly what I was thinking. YOu cant boost over 10 psi if you dont have an fcd or stand alone. I would get an fcd and safc2 and walbro pump before you even think of turning the boost up. or wait for a stand alone. Ill bet if you were too hit 15-18 psi with that turbo =good bye motor.

 

fo sho, sounds like your hitting fuel cut

 

Im on the stock ecu, vert ecu, so I dont think it would have fuel cut.

 

No I experience almost no lag, its actually boosting very nice. But its a 98 backside..

 

First, is this the XS Power / Stone Racing / Master Power / SSAutoChrome "T70"?
If it is, it's a piece of ****.

Second, don't be boosting that turbo with the stock ECU.
It's going to bite you in the ***.
Seriously folks, stop getting cheap with upgrades.
It's going to cause you end up with a very heavy paperweight in your garage.


-Ted

 

What do you have your boost controller set to? And you're going to kill that engine without at LEAST an S-AFC and a FCD and a upgraded fuel pump.

 

^^ agreed

I must agree.

You have a turbo trying to push way too much for what your setup can handle... my 2 cents.

 

First of all, the last thing that I am cheap with, is my upgrades. The turbo is a masterpower, but definately not one of those ss autochrome *****. The turbos that ss autochrom sell is a joke. If I find that this turbo isnt able to handle the power that i am looking for (which I doubt), then I can always buy another turbo..
I'm waiting for friday to buy the haltec someguy is selling.. The ecu with the injectors makes the car run rich. I am aware of the risks, but all I wanted to know if it was something associated with igniton or the ecu itself, maybe the pressure sensor...

 

your hesitation is a simple lack of fuel..your pump can't keep up or your injectors cant...same as fuel cut..well..no worse..because you have not enough fuel WITH air so you are running very lean

 

I have heard of people being able to run atleast 10psi, with the same setup and safc if not more... I dont have an safc, but if anything that should make me run a bit rich..

 

What pressure sensor are you using? It's either detonation/lack of fuel/too much fuel, or more than likely boost cut.

 

if it is detonation, then I give props to the ra seals.... I hit that spot a bunch of times, but I doubt it. Before the build, I had a similiar problem, only it was on the n/a motor. It ended up being part of the harness that had faulty grounds..O no wait, it was a wire that the insulation melted and it kept grounding itself.

 

have you done a compression test lately?

 

If you're using the turbo pressure sensor I'd bet it's simply boost cut.

 

sonicrat got it....
10 psi, bone stock car, and a owner that doesnt know if he has a fuel cut defender or not....

well.... weve got an answer

 

Oh jesus tap dancing christ....its fuel cut.

Lessee......10 lbs....sputtering....hmmmmmmmm


The fuel cut cuts fuel to the rear rotor.....so the sputtering is making sense.


From what i hear a realtek chip is a good thing to have as opposed to a fcd. The realtek has built in 720 support, and built in fcd, and other goodies that you could definately use..




its fuel cut...i almost guarantee it.

 

lol, you should not be modding your car without at least minimal to average knowledge about these cars. You can't just slap a larger (much larger) turbo on it and some bigger injectors and call it a day. Like all the others have said it is asking for disaster. Do a search on rtek 1.7 or fcd. If I where you I would go stand alone but if your going to be trying this for some reason before you get the haltech friday then you need these upgrades

720cc primaries
1000cc secondaries
SAFC
fcd or rtek 1.7 (rtek is nice because it retards timing as well as other stuff)
wideband o2 sensor and laptop to datalog with or bring your car to get tuned ASAP!!!!
larger fuel pump (search for walbro 255 or go to rx7.com and get their fuel pump)


if anyone can think of anything else chime in but this is the main bulk of what you will need to protect your engine against big big problems. Probably not having an fcd has saved your engine so far.

 

he is using a t70. He could run out of fuel quick. 550/1600 is the cheapest and everyone has maps for that.

 

As a quickie test, unplug the boost sensor at the electrical connector.
BE VERY CAREFUL WHEN DOING THIS!
Drive the car slowly into boost.
Does it hesitate still yet?
If it doesn't, it's the overboost fuel-cut.


-Ted