Ok, so I have a butt stock TurboII (well it has a fuel cut defender cuz it bogged like a M/F) and after 35/3700 rpm or so it doesn't pull as hard as I want it to pull. So i was thinking that if I put some RC 750cc on the secondary's it would give it a little extra kick. My question is if you guys thinks this is where I should start (because I hear these rx7s are starved of fuel) and if so will it be safe? BTW its an 87. Or should I start somewhere else.

BTW I didn't know if this is the right section to ask this question, sorry. thanks in advance.

 

bone stock? no need for bigger secondaries.

 

Verify your twin scroll system is working properly, and check/clean all the ECU grounds. Larger injectors are not recommended if everything's stock.

Adding more fuel will not give it any more kick. You need more air AND fuel

 

this

 

Ok i know i sound like an idiot but what the hell is a twin scroll? As for the grounds, i had that problem where it would bogg out at 35/3700 and i fixed it. Now it just doesn't kick like other turboII's do.

 

Ok so the admin. didn't let me edit the last post, I read up on twin scroll and from what i understood its basically the length of the exhaust manifold. Something about the exhaust gasses flowing in sequence which brings me to my question, how do you check for a faulty twin scroll on a turboII?

 

^ You only have 30 minutes to edit your posts.


You may have a secondary fuel injector issue.

If you want to check your secondary fuel injectors for leaks you can strap/secure the injectors to the fuel rails. Unbolt and remove the fuel rails. (There's an illustration of this in the 88' FSM. "Fuel and Emission Control Systems" 4B-74) - Obviously you do not remove the injectors or any of the fuel lines. Be sure to set some rags or something under the injector's fuel outlet nozzle, to absorb fuel in case they are stuck open. Jumper the yellow fuel pump test connector at the passenger side strut tower, near the AFM. Turn the key to "ON"... Not to "START". You'll hear the fuel pump running... Now go check the injectors to see if they are spewing/leaking.

If you do not have a Factory Service Manual, here is a link to the 1988 FSM "Fuel and Emission Control Systems": http://foxed.ca/rx7manual/manuals/19...TEMS_TURBO.pdf

If you choose to go with 750cc secondary fuel injectors, you might as well buy a better flowing exhaust and an Rtek 1.7 -> (Digital Tuning: S4 Rtek7)

 

I would love to do that, however, I have seen many threads that start "Rtek 1.7 blown motor complete part out" or something to that affect, So my question once again is, how safe is it? or are "they" doing something wrong?

 

I've not read any threads or even heard of anyone blaming Rtek for a blown engine. You'd think if it were such a common occurrance, Digital Tuning would pull their product. You can read all of the information about it with the link provided above. Contact them if you'd like.

If you're on a tight budget, Rtek isn't such a bad route.

 

Its as easy as this. Its not Rteks fault its the TUNERS fault or whoever is playing with the tuning device. Unless the motor is tired, faulty wiring, ect ect

 

Well to start I never blamed Rtek. Second, over the years (at least five) I have seen enough threads that state something to what I posted. But at the end, that is why I started this thread, for this vital information that you guy's provide so please have some patience when I ask these questions. Im just tired of shop's or tunners trying to rip your bank account into their pockets when the rx community is just looking for a little power upgrade without blowing your motor or braking the bank.

 

I never once said that you blamed Rtek... I also do not think I'm being impatient. I'm trying to provide you with some reasonable options. If you want to go with something different than Rtek, go for it. It is your vehicle. A few other options would be an air flow controller or an aftermarket EMS.

 

Twin scroll is the system by which the S4 Rx7 uses to control the spool of the turbocharger. There's a flapper inside the exhaust manifold that directs exhaust gasses towards a certain angle at low rpm, then a vacuum operated plunger moves the flapper away to allow the full force of exhaust gasses to the turbocharger. (in a nutshell, that's the best way I know to describe it)

 

all this has been covered about a billion times.

 

Here's another great site for some general TII research which will help you out:

http://www.fc3spro.com/main.html

 

first time i have heard this stuff its good im learning about this cause my 87 turbo2 has warm idle problems

 

this doesn't apply to idle issues, in fact none of it applies to anything but adding boost beyond 10psi.

fix the car first and mod it second.

 

Just wanted to update on this issue. I decided to eliminate the cats via down pipe and eliminate the second cat and it feels like a turboII with *****. I don't know if the cats were clogged or just restricting too much but it feels like a true turboII. Thanks for the input

 

When you start removing intake and exhaust restrictions (cats, stock air box etc) you increase the likelihood of boost creep ESPECIALLY on an s4 which has a very small and inefficient wastegate. Its time to invest in a real boost gauge.

 

Be very carefull with boosting the car now,you removed the cats so that turbo is breathing better and you might be overboosting it and it will cost you and engine.

 

^ Yep.

Time for Rtek 1.7, aftermarket boost gauge, 720cc secondary injectors, and a wastegate port.

Otherwise, blow that bitch up!

 

Not one single thread like that...however...

Lot's of threads like this:

I gotta brand new free flowing exhaust and a boost cut defensor. Wow! this ting gots *****!!

( new thread) F.S. Roller Blown engine....


You're next.

 

And maybe a wideband gauge

 

I believe you should get or make an exhaust restrictor plate to bring boost creep back to something manageable for right now. That's cheap and EASY to install until you can afford at the minimum:
-ported wastegate (nearly free)
-boost gauge (sunpro makes a decent one for $25)
-wideband (about $200, but a necessity if you're going to play)
-fuel controller (at least an Rtek, don't use an SAFC, they're worthless)
-fuel system upgrades (720cc secondary injectors is what I use)

You don't have to get them all at once. If you do go on with it, get the above mentioned stuff in that order. Once everything's in place, you can get a manual boost controller and start having some fun, safely.

I know it sounds like we're a pack of dogs jumping on a 3-legged cat here, but we're just trying to help you have maximum fun, safely, without killing another good engine.

 

I appreciate the heads up and all the info. I'm sure I can do all this good stuff myself, however I have never ported a wastegate. nevermind I found an article good old Aaron Cake. Also I don't know what an exhaust restrictor is or how to make one (or buy one for that matter), again any leads to a thread about this subject would be much appreciated. thanks.