FCuLater

Hi everyone. I recently purchased an 89 rx7 gtu and it seems to run pretty well. I did kinda have some concerns though, it would make sense to me that with stock hp ratings of 160 hp (S5 NA motor with 130k miles) That i should be able to at least burn the tires a little. the most i get out of it with about a 6k dump is a few little barks. I'm only sitting on 16x7s so i don't believe wheel size is the issue. So my question is am i expecting to much from a 23 year old motor or should i be looking for a possible condition causing power loss? Used to own a RX8 but never an RX7 so any info you can supply would be great. Thanks.

Aaron Cake

iTrader: (1)

It should spin the tires pretty well if dumped from 6K.

Could be a number of things though.

Slipping clutch?

Check to make sure both the aux intake ports are functioning, and that the VDI is working correctly.

If it's totally stock, maybe the cats are clogged?

FCuLater

I was kinda thinking it should burn pretty well. The previous owner just recently put in a new clutch and it feels pretty good. The idle is a little rough but clears up a little if i unplug the TPS. The 5th and 6th ports seem to be working ok as i have power through the whole band. pardon my ignorance but what does vdi stand for?

i have been meaning to check the cats as well. the PO put what appears to be a makeshift flow through on it so that needs to go for a racing beat system later on anyway.

waldog

iTrader: (12)

My 88 GXL can burn the tires off if I tried. I had a 88 vert that seemed to have what you're explaining though. Maybe the car has been beat on to much?

Also, a note to you. Make sure you're not popping the clutch at 6k, your post says you made the tires "bark". You will snap the half shafts by popping the clutch really fast. I use to do this to my vert and the tires would "bark". Until one night I snapped a half shaft. They break easily if abused.

hitlittle1

Ether the engine is shot and needs to be rebuilt, or your losing power somewhere along the drivetrain, any weird noises when driving along?

oh I just read the cats part, yah check to make sure everything is flowing, sometime the injectors can get clogged with shity gas, or carbon build up in the exhast and engine, just check everything over, the cars over 20 years old

LizardFC

iTrader: (1)

My advice would be to ditch the cats. At 130k they're probably not flowing that well. Also, try running some Seafoam in the tank. I use 1 can with about 1/8 tank and apply the throttle liberally.

FirstRotaryExp

iTrader: (3)

Man, another FC...in my own backyard no less.

Though maybe something nobody is considering, what tires and sizes are you running? Sure a 16x7 seems 'big' but really thats at best a 205 series tire, maybe a 215 or 225 (rears only unless youve got some good aftermarket offsets). A sticky tire wont 'burn' in an NA application, at best you'll get a 1 tire fire (Open dif on all S5 models unless T2 for the most part). Though another thing to consider is that its been hot as ***** all month in the area, hot roads = more grip which is whats going to happen when all you get is a chirp.

And honestly 160hp is not RWHP, thats flywheel rating to make it look good, and when it was new. Though why are you even wanting to burn tires off is beyond me, I tend to not want to give the local PD's a reason to ALWAYS eyeball your easily spotted car (maybe 4 FC's within a 30 minute drive, with a few more in knoxville). And frankly Dandridge, Jefferson City, Morristown, Newport, Jeff county, Cocke county, and Hamblen county PD's tend to notice car's that stick out.

Advice would be to replace teh exhaust, get a good compression check (to see how much life you may yet get out of the motor but plan on around the 175K mark to be prepping a rebuild just in case) and invest in a fuel controller of sorts to tone down how rich NA's run stock.

PS, if you happen to be looking for parts I may have quite a bit of stuff for sale soon (suspension, wheels/tires, maybe a turbo driveline, and a fuel controller to name the big stuf). But if you need some local help im between dandridge and newport and usually try to help the local rotorheads.

whonderman

Check all the easy stuff before you head ***** deep in the motor. You may just need an adjustment on the slave cylinder if you haven't checked that already! Had issues myself with the slave.

FCuLater

Thanks for the advice everyone. I don't have a whole lot of Rotary experience so everything is helpful.

The PO happen to weld the exhaust on right after the cat so checking that will not be an easy task so I'm kinda hoping that isn't it.

I did recently adjust the tps and it seems to run a little stronger. everything i check puts a few extra ponies back. I did notice the other day ( while adjusting the tps) that the front actuator on my aux ports was extended while the rear wasn't. Again i was adjusting the tps so the car was hot but not running so they should have both been retracted correct?

I haven't noticed any strange noises from it other than a slightly rough idle at times. not a constant but at times it is rough and others it isn't. some of the times when it is idleing rough i will notice a back fire or two as i change gears. this coincides with the biggest lack of power.

I believe the tires are 225's. they look pretty new but nothing fancy. just all season all in one store tires. I have something alot like them on another car i own and they grip ok on it but not great some squealing in heavy corners. I'm not really looking to burn them off all the time or even frequently for that matter. Dandridge isn't real big and the men in blue dont have a whole lot else to do than pass out speeding tickets. It's more of the peace of mind that goes with knowing I'm able to on demand that I'm after.

Again thanks for the help. next step is clean up the aux ports to make sure they aren't sticking and then probably exhaust (don't much care for the sound of it anyway). Will post more as I know more.

FirstRotaryExp

iTrader: (3)

Fact of the matter is unless you have a Turbo model, being able to make long lines of black rubber are nigh impossible with a rotary. There's not enough torque, and youd have to have crap tires or clutch dump to even get them to spin for a few moments. A grippier clutch may also help in some situations, but if you are only 'barking' tires you may also have a busted front dif mount thats allowing the dif to flex enough break tires loose for but a moment. but as mentioned, you will break a halfshaft or axle stub in the endeavor for a burnout.

FCuLater

So brief update for those of you still following. With a quick cleaning of the aux ports car runs and drives quite a bit better. More bark less dump. My original concern was that of a dead or dying motor. So far things seem to be ok. A little less punch than I was expecting ( but after my RX8 I guess its kinda expected). Overall still very happy and looking forward to good build. Thanks again for all the advice.

cab91089

iTrader: (3)

Next on the list should be a compression test, that will give you the best idea of what to do next... Rebuild the engine if low compression, leave it if its ok compression and mod it or what ever your plans are with the car.

snivley whiplash

iTrader: (4)

do a compression test and find out if the engine is up to standards, it should blaze the tires if the clutch is in good condition and you are cutting it loose at 6 to 7k if not..look at a new or rebuilt engine(not motor) and go from there. my fresh stock 6 port will blaze the skins in third with a hard clutch launch. dead stop.......1 2 3 blazing the tires your engine is worn out, sorry but a rebuild is in store.

twin3037

no point in modding unless you have a good base to start with