Greetings all,


I know this is a stupid question but I need to get
some reference point. How much boost I need to
blow the Apex seal, 15-17-22 psi???

I have a mid pipe in the mail and I just want
to play safe with my boost.

thanks all!
Serge

 

We need a little more info, like what year and if there are any other mods done to the car. You can damage a rotary with as little as 12psi in some conditions.

 

i think he meant to say...with efficient fuel/air mixture what is the highest boost he can go up to before blowing the motor.

I think it's 15 PSI...higher will bring trouble. When I first put my DP/MP, I ran like 16 or sometime 17 PSI when secondary kicks in, felt great, but I know it wasn't safe to run like that in the long run.

Now I always run 10 PSI on the street/normal, then crank it up to 12 or 15 when a Vette/Porsche is next to me.

 

The stock fuel injectors hit 100% at 14.7psi of boost. If you still have the stock ecu your limited to 10-11psi of boost but if your installing a mp I assume you've already done the computer upgrade.

If you want to be safe keep it around 13 psi

Later,

 

well, there are FDs that run up to 1,5-1,8 bars (~ 23-24psi), but with more mods that I care or have time to mention

More boost means shorter life span, 's all. "Shorter" could mean mere minutes , several months, or five years. It all comes down to how many mods, quality of work, and peak pressure, all in conjuction.

 

I say take it to 20psi.......YA

 

Sorry that was a joke dont try it.

 

I was running about 18-19 PSI in my turbo II with a rebuilt motor from rampage in NYC.

i eventually blew the motor on a really cool night doing about 160. but thats my falt. the car ran STRONG as hell and i didnt have any problems. i have a g-force ECU for the fuel.

it was awsome while it lasted. now im back to 6 =(

Mike
87 Turbo 2

 

Its all in the tuning, as long as you have a reliable A/F ratio your good. If your just planning on dumping in a upgraded ecu dont run very much. If your getting a standalone computer and having it dyno tuned well thats a whole different ball game.

What are you planning in the way of mods and we can help better

Later,

 

If the right a/f mixture you can go to however much boost you need to reach around 700rwhp so you get rotor housing walk. otherwise whatever boost you get lean out at, you will blow it.

Blowing apex seals isn't boost dependant, you could blow a seal at like 5psi if you leaned out at 7000rpm

Despite what most 'experts' will try to tell you Boost doesn't blow apex seals, leanout leading to detonation does.

 

I heard 14.7 psi max. I am going to use 12 pounds of boost to be on the safe side. Hey!! Its a daily driver.
94 rx7 blk r2

 

Listen to HWO... it's not the boost that kills, it's the detonation!

If your tuning is screwed up and get a bad tank of gas you could blow your engine without even BEING under boost conditions... I found out that contrary to popular belief, a N/A can and will detonate if you get stupid with it. (Fortunately I didn't hurt the seals... or at least, they're still going strong ~20,000kms later)

I've heard many many stories about people just pulling into a parking lot/pulling from a stoplight and *plink*... or the boost sensor hose pops off (T2) and before the owner gets around to figuring out why the boost gauge has stopped working, *plink*...

 

I have heard of running about 15-17 psi on the stock block with the appropraite mods to supply the increase in boost with the necessary things that it needs. I would say that if you are going to increase the boost, I would first upgrade the fuel system, exhaust, intake, and the ECU. Play it safe, and increase a bit at a time.

 

Okay then I really think the RX-7 sucks as a for reliability and potential as a tuner car. I would think it is generally difficult to completely rule out any chance of detonation, extenuating circumstances could easily lead to lean conditions beyond your control in a very short period of time and screw your car. How do you even tune on a dyno without knowing you won't blow your engine trying to get a good A/F. Maybe I should just spend the extra money and buy an overpriced SupraTT which I can tune to 20+ psi and have it ping twice and then I fix my A/F and it's fine, No Blown Engine. But then again the Supra looks fat and is fat. Maybe I should try an LS-1 V8 swap, just save my money up for a LS1 V8 instead of wasting it on mods when my engine is going to blow anyways whether I get a fuel computer and upgraded injectors or not. Yes I think it's a plan.

 

I agree with some of the frustration you're displaying...

Owning a rotary and tuning it is not for everyone, but that is what makes it a challenge...I like the challenge.

But then again, I can see myself following a similar path to jimlab, spending thousands of hours tuning, upgrading, rebuilding...even looking into a 20B, then finally deciding to do the V8 swap...or going to a different car and keeping the RX at a moderately tuned level (tough to beat the look).

Also, I don't know how much HP you want, but there is no reason why you cannot safely tune to 360 RWHP (and more)...if you know what you are doing and do it cautiously. That would be a great runner on the street.

If you want something really cool, why not go ahead and import a Skyline, tune the **** out of it and take everything and anything...all the while having a very rare (in the USA) car.