hey rx7 fans i just was lucky enough to purchase a 1990 rx-7 turbo, this is my first rotory and i have a few questions i played with imports for a while i went from 2 dsms to the vtec scene and now i got a real car im curious as to what kind of abuse can these 13b motors hold up to? ive been told 15 psi for the track and 10 psi for daily is not unheard of ive been told im only running about 5 atm, can anyone also give me some history on the rx7 also? im very interested and love my car i just wanna learn the basics before i really start tweaking =] any help is appreciated, thanks guys

 

You're going to have to be a lot more specific. If this is a stock TII engine, you should be seeing ~8 psi max on the stock turbo. If it's 5 or 6, someone has disabled the turbo duty solenoid (factory boost controller), and you're running purely off the wastegate spring. I wouldn't recommend increasing the boost past about 9 psi with stock fueling. The stock turbo is good for about 12 psi before it starts becoming too inefficient to be worth it, and of course you absolutely need a fuel system upgrade beforehand. Larger secondary injectors, a larger fuel pump (such as an FD/3rd gen pump), and a way to control the new injectors (Rtek, SAFC + FCD, standalone, etc...)

 

In addition to what RotaryRocket88 has stated, before you up the boost, you should make very certain your cooling system will be up to par. If you plan on making more power look into a larger aluminum radiator to help keep temps down, as rotary engines DO NOT like to be overheated (you can get away with it once if you catch it in time, but generally an overheating scenario will cause the coolant seals to fail prematurely indicating rebuild time.)

Take care of the cooling system and fuel delivery, then you should think about the boost pressure increase. Whomever told you 10 and 15 psi for daily and track pressures was very vague, as 10 psi on the stock turbo is not the same as 10psi on a larger unit. But pressures can be ran at whatever level you can tune it for (rotaries will run richer than a piston engine. first gauges to buy should be a boost, water temp, and wideband to monitor things effectively for motor longevity.)

If you keep these engines happy with cooling and fuel, they will take alot of abuse and seem to thrive near the redline (fun tidbit: Rotary engines seem to run their very best just prior to losing an apex seal or 3, also they 'can' run on one rotor if the other has been made in op, just going to use even more fuel).

 

thanks for the replies guys! i do have an upgraded aluminum radiator with a huge fan on top of it, i also have a bigger front mount aftercooler i believe its the stock turbo and im not for sure what boost im running ive been told like 5-10 my bov is pretty loud though i have a boost controller but didnt want to mess with it before i learned more about rotarys, so if i upgrade the fuel got a bigger turbo and tuned it the motor should hold up pretty good stock? thanks in advance!

 

essetially yes. You wont see super impressive numbers as you will be limited by the stock intake ports, but if you do the proper fuel mods it should be decently quick. Ease into the boost increases and find a happy medium until you can afford to have the motor pulled and rebuilt (with some porting to the irons) so it can better use the increased boost pressures.

 

The stock ports are not what limits the car, mainly the stock turbo. At about 12PSI it starts blowing heat, much more so than air.

Are you saying you don't have a boost gauge? If not, that's step 1.

Be aware that after you go above 8 PSI or so (requiring the use of an FCD) you'll have to do something to increase fuel delivery.

 

cool ill have to do some research the car is already quick i was told 247 hp at the wheels i mean quick compared to my old honda... the engine is already rebuilt but i think stock i ordered a boost and coolant temp gauge they just havent gotten in yet my coolant temp gauge doesnt work which makes me scared to drive it. another question i have is how does my radiator efficently keep cool when its mounted inside the engine compartment where no air can hit it besides my fan?

 

heres a pic of the engine what are ports? like intake mani and throttle body?

 

yeah, I wouldnt push the car hard if your stock gauge isnt working, the S5 temp gauge sucks anyway, it gives no warning of overheating, just has warming up, middle, and ooops your screwed. The location of the radiator is actually fairly effective, the only 'better' option is to do a V-mount which would drastically alter the location of both the radiator and intercooler, but theres a bit of fabrication involved with that and a new hood is required.

It looks as though you already have an aftermarket aluminum radiator so cooling appears to be set, though a coolant temp gauge would help keep an eye on temps even more. I cant really tell, but I'm assuming you have fairly substantial FMIC blocking most, if not all, of your frontal grill area? Is the original plastic undertray still in place? Air will still move through the fmic, through/around the oil cooler, then be drawn through the radiator by the movement of the air as well as from the fan drawing air through it. If you are worried you're not getting enough airflow, you can either cut into your existing bumper to open it up (some cut a slot out in the middle along the 'moulding' strip), or you can look into an aftermarket front bumper with a larger grill opening.

 

There is no issue with the radiator. There is an air tunnel formed by the bumper, body and underbelly tray that directs air to to the oil cooler and radiator.

Unless you have reason to suspect the car is overheating, you should not be afraid to drive it without a coolant temp gauge. There is one on the dash which will sit at 1/4 (S4) or 1/2 (S5) at normal operating temperature. But I don't suggest you beat on it until you get a boost gauge and confirm your boost level.