Hi all,

I recently swapped my Evo 4 for a 1992 Series 6 RX-7 and a mate of mine suggested I join the forums here to seek advice on modifications etc.

After reading through countless stories of engines going bang due to unreliable mods I am now scared shitless of blowing mine to pieces.

It has the following modifications:

3 Inch Stainless Downpipe
3 Inch Stainless Midpipe
3 Inch Catback
Sard Fuel Pressure Regulator
Walbro 500HP Intank Fuel Pump
GReddy Intake Kit
HKS SSQV Dump Valve
Gizzmo MS-IBC Electronic Boost Controller
Innovate Motorsports G3 Boost Gauge
Innovate Motorsports G3 Air/Fuel Ratio Gauge Kit (LC-1 Wideband Controller, Bosch 5-Wire Wideband O2 Sensor)

Now my question for you...IS IT SAFE?

Your help and advice is much appreciated.

 

stock ECU? what are AFR's? what boost are you hitting?

 

Most blown motors are caused by too much boost or bad gas. Buy the best gas you can, premium only. The key to keeping the motor happy is keeping it cool and keeping the maximum boost where it's designed to be.

I assume it's set for full boost now. I would turn down the boost to the minimum (probably 8psi) and watch the AFRs under increasing load. Also watch the boost level and make sure it stays solidly where you set it under full load - with such a free exhaust you might see boost creep where the boost just keeps climbing, and that would be bad.

If it gets as lean as 12:1, stop and decide if this is enough boost for you or to get the ECU tuned. (If it's a stock ECU, you shouldn't go past 10 or 11psi).

If you get to full boost and still see no leaner than 11's under full load, you're probably quite safe. There's a lot more to tuning than this, but at least you'll have an eye on the safety of your motor.

Take care that for any FD it's very important to have a perfectly maintaining cooling system. That includes radiator ducting, radiator and AST upgrades, fresh coolant hoses all around, thermostat/radiator caps, etc.

 

I would also get an upgraded intercooler. For ultimate safety an AI system is recommended. Like the geese has mentioned before, make sure you get a shop to tune the car right. Thats probably the most important thing you can do.

If you notice your water temps creeping up in traffic, you can turn on the heart or AC and that should make your rad fans run at a higher speed so you the water temps go down.

You may want an intake box but people don't really say its a must have item. I try to be extra paranoid with my car and will be putting in another round of mods as well, followed by a tune.

Anyway, enjoy your FD!

 

Yes the ECU hasn't been modified.

A/FRs change depending on boost I am hitting.

With the boost controller switched off it hits 0.7 - 0.8 bar and AFRs 12 - 13.

With the boost controller switched on it hits 1.0 - 1.1 bar and AFRs 17 - 18.

 

Also with the boost controller on it hits 1.0 - 1.1 bar then boost cuts.

 

you're in "oh ****" territory right now

park the ******* car and don't drive it until you have some way of tuning it

 

So under full boost what should the A/FR be to be safe?

 

That is not what I want to hear...

What are my options as far as tuning goes without going standalone?

 

you could roll the dice and get a chipped ECU. but with those mods I'd say your real options are:

option 1: standalone (Power FC is most common) + tune + ported wastegate

or

option 2: blown motor

 

Plus get Auxiliary Injection. howard coleman sold me on the theory of upping the octane as well as steam cleaning the engine, all in one shot.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/making-case-rotary-powered-fd-fix-806104/

 

Sole reason why I will be doing the same.

 

What if I get a Pettit ECU, port the wastegate and limit the boost to 12psi?

 

He told you right on that post that you quoted.

The responsible thing is check your WIDEBAND AFR... after your upgrade.

Dude the best advice is to get a stand alone + tune. In other words more $$$. if you want to go the non expensive route you bought the WRONG car. If you are dead set on not spending cash only add mods that keep the car cool (DP, IC, Intake) and limit boost to 10 psi. Even still get A.I.

The FD is worst car to cheap out on. If you think spending 1K for a PFC and tune is expensive wait till you blow your motor. Even better sometimes when a motor blows and if the owner is lucky enough, the turbo sucks that apex seal for a second round of fun in tearing **** up. Now that's expensive...

Bottom line FDs cost $$.

 

Assuming everything else is up to par on the car the above will result in a really quick and reliable fd. The pettit ecu is a great plug and play as long as boost doesnt excede 12lbs. But as said above, you are in "oh ****" territory right now.

 

Whoa. Not good.

WAAA!! SCARY!!!

PS: if those are your AFRs while at 1 bar, it's a minor miracle you still have compression enough to start the car. 17-18 AFR might be normal for cruising or off-throttle, but under load any AFR above 12:1 requires a tuner who really knows what they're doing.

 

I would not go 12 psi with a petit ecu. Search a bit, but even that is not reliable. Set to 10 psi unless u have PFC + tune.

All the money you spent on the mods so far (assuming you did spend the money and they didnt come with the car) .. so a PFC + tune wouldnt be that much compared to the $$ spent on the mods you already have.

+100 to the AI injection. standalone kits are like $300-500 .. unless you want the really smart ones that are discussed in the thread above.

I'm surprised that the AFR reading you posted of 17-18 hasn't blown the motor already.

Drive with a light foot my friend

 

It's too late.

Engine went bang 2 nights ago.

 

Extremely sorry to hear but we tried. As you now know first hand, rotaries are extremely unforgiving to detonation. If modded right they will last, and make gobs of power . Cheap out or make uniformed decisions and game is over.

Welcome to the club that no one wants to be a part of