I Have a new high performance rebuilt 3mm apex seal engine that Monday I did my first oil change at exactly 500 miles. I have kept the engine under 4000 rpms and no appreciable boost. This problem was actually there with the original engine. There is a terrible bog between 2000 and 3000 rpm. This bog is so annoying that I want to get rid of the car after only 500 miles. My car is a 1987 Rx7 turbo II with a hybrid Garret/Hitachi turbo with the twin scroll manifold modified and ported into one single manifold. Please help Me!!!

 

What's your air/fuel guage saying around those rpms?

If you're not running ritch then I'd assume:
1) dirty primary fuel injectors
2) TPS
3) tuneup is needed

Had a chance for any rotary mechanics to look into this?

 

Have you done the throttle body mod on this car?


-Ted

 

What throttle body mod?

 

This is a brand new motor with under 700 miles on it, injectors were cleaned professionally.

 

you could trade it to me for my gxl, i have no anoying hesitation such as this.

james

 

I could not subject you to such problems. I think I'll set on fire if no one can help.

 

bumpity

 

I have the same problem with mine with a recent rebuild, well 34g miles ago, my solution is to launch at 4grand then you don't even have to deal with it hehe

 

Black RX7: I feel like holding that B__ch to the floor till it blows up sometimes. It is just that aggravating with a new motor.

 

i agree with black rx7. if you start above 4grand you will be fine. maybe a mod to both the throttle body, intake and new high flow exhaust may help you. I don't have a turboo but I did have that problem untill I put a high flow exhaust and cool air intake on. The car is worth the hassle once you learn what is causing certain problems and learn the trix to fix them.

 

Starting at 4 grand I will smoke the crap out of the tires everytime I take off, I have K&N intake and full offroad Racing Beat 3.5" exhaust. But Thanks anyway BPRESTON.

 

I have the same problem with my '87 Turbo II with 500 miles on a rebuilt engine. I rebuilt it myself, but this car had the "no low end" problem before the rebuild. I have been trying to track the problem down for a while now. I know what you're going through. I laughed when I saw BlackRX7's reply about launching at 4k. No offense to "BlackRX7" but that's kinda crazy for a street car, and my car will burn the tires well through second when I use that method. I have a K&N filter and full Racing Beat exhaust with FCD. I've been talking to Hayes Rotary about this problem, I'll keep you posted on what I find out.

- David
'87 Turbo II
'88 Turbo II
'88 GXL
'89 GTU
'88 Convertible

 

If you want to throw the car away after 500 miles of anoyingness.. Do it now and save yourself another 500+ miles of it... These cars are not made for people who are used to driving camry's and Escorts...
In my oppinion, I do a crap load of maintenance on my seven and it still catches up on me.. The problems stack up and it's hard to keep up.. and I'm not happy with mine now.. but I've had it for a while and I'm getting used to it... They are also old cars .. So either get used to it or sell it That is my oppinion... Sevens make much better project cars than everday drivers IMO

 

I was refering to when you need to get up and go, aka drag race, street race, why would you complain about no power at low rpms when you don't even need it when your driving daily through the street, unless you plan on racing someone and reving it to like 1500rpms when you launch YES i garentee that even if your slamed on the gas it won't get up and go untill 3k, this is also attributed to turbo lag, by using the s5 turbo and manifold there is a signifacante amount less of turbo lag and boost creep.

 

When you say bog, do you mean it stumbles or splutters before clearing and acceleration? Or just smooth but slow acceleration until boost arrives around 3000rpm? If it’s stumbling, it could be a dodgy TPS or other electronic problem. Otherwise it sounds like typical behaviour for a turbocharged engine designed in the 80’s. Most turbo cars of the era were quite laggy, especially when compared to today’s cars with far more advanced turbo designs. That probably won’t be helping at all. The S4 turbo was designed to work with a divided manifold and the twin-scroll in place. Seems logical removing it would affect the rate the turbo spools up.

 

If trbospd's problem is anything like mine, it's not a turbo lag problem. My car actually hesitates the nose goes down and the engine stumbles for a second and never really recovers until boost kicks in at about 3000. Sorry BlackRX7 if I insulted you, I see what you're saying, but this is more of a problem than just turbo lag.

 

Green, I have never owned a typical daily driver, I have always had sports cars. The only daily driver I have ever owned was a 1994 suburban. I bought that just to trailer a 800HP 300zxtt, which I drove daily until a month ago. I have been having this rx7 since 1991. I also have worked on BMW's for 14 years, but rotaries are completely different animals. I am boggled at this point, have tried replcing and adjusting everthing I can imagine all by the book.

 

First off guys I am not a turbo owner, but I have been reading alot of technical info on stock rx-7 turbo setups so that I can turbo charged my oval window. My best advise to you would be to go out and get you repair manual that has all the ohm reading in it and start checking sensors. I highly doubt that your hesitation in mechanical, I would bet that it is electrical.

Start with your boost sensor, and secondary fuel injector resistor.

Good luck, I hope you find the problem.

 

Thanks I appreciate the support. But I found out the problem. It was just that the plugs and chambers were so loaded down from "Grandma" driving while breaking in the engine it just needed to be run like hell and back the timing down. After the smoke cleared my highly modded rx-7 literally ran like a bat outta hell! Thanks again, Vin.