88Rx-7turboII

iTrader: (2)

About how much boost can a stock setup withstand on a TII? is it possible to crank it up any? if so, what is the easiest way?

Turbo II Rotor

iTrader: (2)

Don't scrap the car after you blow the motor.

RETed

1.0


-Ted

Evil Aviator

You can get up to about 8psi boost without too much trouble. The cheapest way to increase boost is to install a manual boost controller, fuel cut defenser, and aftermarket boost gauge. Rewiring or replacing the fuel pump and porting the wastegate would be a good idea for safety, and adding a cat-back performance exhaust would help produce more power.

88Rx-7turboII

iTrader: (2)

I was already planning on a cat-back and when you say to port the wastegate, would a bov be kinda the same idea? And what website would you suggest?

88Rx-7turboII

iTrader: (2)

Why do you say it's going to blow the motor?

JYM

Because when you run too must boost without upgrading your fuel system, you're going to be very lean... and then... bye bye engine...

88Rx-7turboII

iTrader: (2)

How much should i upgrade? would fuel pump and injectors be enough?

Craiger

iTrader: (1)

Hmmm... how do i want to answer this... NO!!! A BOV is there to prevent compressor surge when you shift or let off the throttle. A Wastegate re-routs exhaust around the turbine preventing your turbo producing too much boost. Completely different jobs.

Manual boost controler, fuel cut defender and an upgraded fuel pump can probably get the job done to up it to around 8lbs or so, but i would find someone with a wideband and gingerly test it before you take any hard pulls.

Hmmm.. just noticed yur in NB, I'm down in the Halifax area. Not many RX's in Atlantic Canada, good to see another.

texFCturboII

iTrader: (17)

I'm running 11lbs. of boost max on my stock turbo. I've got 720cc secondary injectors, an FCD, Electric Boost Controller, S-AFC to tune the fuel curve, no problems.
you MUST upgrade your fuel, and have a means to control it when you up the boost. a wideband is VERY helpful for this kinda thing too.

Evil Aviator

It is important for you to realize that you are currently totally lost. That isn't a problem as long as you do some research BEFORE you install anything. The engine can blow up if you install some products without installing others first.

Click on the link in RETED's post and read through the information there.

88Rx-7turboII

iTrader: (2)

well the reason i started this thread was because i don't know much about tuning and upgrading so i wasnt planning on buyin or installing anything until i got the right feedback. i appreciate all the posts. And i was told that if i were to install a bov on my current stock setup by just taking off the existing stock on and putting an aftermarket that it would throw codes because the air isn't being returned to the airbox, would this still happen if i upgraded to the cone filter intake system with the maf adapter?

Oh and craiger, you're right about the rx's. I just got my TII in october and it was the only turbo i could find for sale on this side of Canada.

texturbofcII, what are you running for primary? just the stock 550?

Evil Aviator

Good, that's smart.

Installing a BOV on an FC RX-7 will not throw any codes that I am aware of. It will, however, upset the fuel/air mixture when it operates, causing a little bogging between shifts. If you are worried about it, just buy a Compressor Bypass Valve (CBV) rather than a BOV. Actually, if you are only going to run about 10psi boost, you don't even need a BOV or aftermarket CBV unless you just like the noise it makes. Personally, I would spend my money elsewhere.

The CBV returns the air between the MAF sensor and the turbo, so a cone filter will not make any difference.

Also, FYI, the MAF sensor on the FC RX-7 is more specifically a vane type Air Flow Meter (AFM), so the "AFM" term is more common in the RX-7 community.

texFCturboII

iTrader: (17)

yes, they will suffice with the stock turbo. I'm planning on upgrading my secondaries to 1600cc's and dropping in a BNR stage II or III, and moving the 720cc's to the primaries, but with the stock turbo, the stock primaries are fine. Upgrade the secondaries to something bigger, keep in mind what series you have and what impedence injector (low or high) you need. read RETed's links....... VERY HELPFUL!!!!

Phantomkid

Good idea to research before installing parts. And this definetly is the right spot, you have some much to learn. The stock unit is good concept, recirculating blow off valves are better then ones that vent to the atmosphere, it helps prevent turbo lag.
Most people start upgrading the exhaust first which is a good idea because of the restrictive stock exhaust. But the problem being now the turbo doesnt have backpressure and can spool quicker and more effiently, down flaw being mazda didnt design the turbo for the increase effiency and the stock wastegate can not support. If the wastegate is not ported the turbo will start to boost creep( Creating more boost that is not intended) because if can not let enough exhaust bypass the turbine.
The fuel cut is a must atleast fc3s website has a do it yourself, i recommend at least doing that till you find some way to manage your fuel.

Craiger

iTrader: (1)

Yeah I bought my TII a little less than 2 years ago when I was living in Vancouver. I got it cheap cause it is high km's and for a while it had been somewhat neglected, but it turned out to have some good parts on it and she is strong now after I did a rebuild.

Come to think about it if you end up needing a fuel cut defender I have one that I don't use since i'm running a megasquirt.

Is you car stock or does it already have any mod's made to it, and did the previous owner take good care of it??

88Rx-7turboII

iTrader: (2)

As of right now it is completely bone stock. The guy i bought from owned it for 15 years and its only got about 146k on it. The guy said he stored it every winter and it runs really great.

I've got an BOV on the way right now and it's an atmospheric type, is there something i can install to make it run without any upsets?

RETed

ONLY 146k miles?
That's about the limit on mileage on a "healthy" motor.
I wouldn't advise pushing the power upwards until the engine has been rebuilt.

Trying to extract more power out of an engine with that kinda mileage is going to reward you with the apex seals spitting out of the engine in a jiffy.

Sorry to put a damper on your plans, but getting the engine rebuilt is highly recommended before looking for more power...


-Ted

texFCturboII

iTrader: (17)

I think that's 146 kilometres, he is canadian....

Craiger

iTrader: (1)

I think it will run ok, just when the BOV opens the MAF will be pulling in more air than is needed and the ECU will effectively run the engine rich for the split second while the BOV is open.

The only way to prevent this is to remove the stock ECU and replace it with a standalone... but that's going to run you min $1000+ for the hardware and someone to tune it.

The only real reason to put the BOV on there is to get the "woosh" sound when you shift. So if you really want that i'd just put it on anyway. Otherwise I wouldn't bother putting it on and either resell it or save it for down the road if you start making more upgrades.

Craiger

iTrader: (1)

Nice, sounds like you scored a good one. The km's are not bad, probably still a good idea not to go above 8lbs of boost unless you want to rebuild the engine first. Remember, everything inside the engine is 20 years old... for big boost some new internals would be a good start.

Definitely check your air/fuels to find out how safe the car is running. If it's running <12.0's under full stock boost then your probably safe (as far as air/fuels goes) to bump it to about 8lbs of boost. If your >12.5's then there is something going on with the ECU and upping the boost would be dangerous.

When I got my car it was running 12.9's at 5lbs of boost. One of the reasons I scrapped the stock ECU and harness and went to a megasquirt!!!

88Rx-7turboII

iTrader: (2)

I have had the engine compression tested and everything came out fine. How big of a job is it to rebuild a 13b?

phoenix7

max is 12 psi for me. GEt a fuel controller, wideband and maybe bigger secondaries.

You should have searched.

Craiger

iTrader: (1)

How much compression did it have??

It is probably about 20-30 hours to do the full job depending on what you find when you open it up. On the plus side with the condition it sounds like the engine is in it sounds like almost everything except seals and gasgets should still be good.

I guess it depends on what your power goal is. Bone stock would be looking at 186hp at the crank. If your looking to move into the 190's then upping the boost can probably be done safely. If your looking to break 200 then you should probably rebuild it first. No one can say for sure if you could get away with going higher without a rebuild or not, but if an apex seal breaks then you could cook a housing, a rotor and your turbo pretty easily... in my opinion it wouldn't be worth the risk.

88Rx-7turboII

iTrader: (2)

The compression test came back with everything over aout 105. Do you know of anyone local ( meaning around the maritimes) that do rebuilds? and about how much would it be saying that all i need is seals and gaskets?