SoulPyr0

Hey, i have a 1991 convert pretty much stock.. and i need more low end torque to get up with the comp. in a race or what not... i just need more low end power... plenty of top end power but, i am confused on what to do and will advancing the timing help me any ?
Please... SOMEONE help !
private message me or something... i need power ! I am gettin exhaust this weekend but, i wolnt know untill then if it helps but, i need madd help..>!!!!

hanman

If it's not an automatic you can put a lightened flywheel on, it will help with the launch.
hanman

SoulPyr0

It's an auto... (crying)

SoulPyr0

I just need something that helps off the line between 1000 and 5000

hanman

I have a 90 vert with an automatic also. It sucks off the line. Especially if you don't come to a full stop, it still is in the higher gear and it is a real slug. Mine is street ported, but I haven't been able to really go out and tromp on it yet. I only have 200 miles on the engine.
hanman

SoulPyr0

hmm... i have a 91 black auto... and i agree it sucks off the line
i wanna cry
Everyone says that rotarys are good off the line...

No7Yet

Uh, how involved do you want to be? You could do many things to up your torque numbers, but a buddy of mine reported great midrange butt dyno hp gains via an MD Race remapped ECU. Don't ask me where to get one, I don't know

Have you made sure that your 6PI is working?

More involved, you say? First, ditch the auto - that's what's killing you, trust me. Can't do that? Uh, you could shim your LIM to move it out, away from the ports... longer intake ports = higher flow velocity = more low end, at the expense of top end. You could design a custom, 2- or 3-path intake manifold, much like what's used in the RENESIS... but that's mucho $$$.

Basically, though, it's just the "nature of the beast". A rotary matched to an auto means no bottom end.. sorry

Brandon

finky

iTrader: (2)

I bought mine w/ 5 speed for a reason. Anyway you should be able to change the torque converter to a smaller one (higher stall speed) I have never taken apart an auto rx7 but it should be like any other auto I THINK

No7Yet

OH! I ALMOST forgot! There's the ONE thing you can add to ANY engine that's almost guaranteed to add ALL THE TORQUE you can handle (until your engine goes "pop")... wanna know what it is?




... okay, then I'll tell you!....







FORCED INDUCTION! Muhahahahaha! My 89 TII has GREAT pull at about 2500 RPM!

Brandon

SoulPyr0

1. Ok, explain that to a blonde...
2. I have not a clue on what you said....
3. What's the cheapest way to get good hp?
4. Help me !
haha...

tmak26b

NOS

SoulPyr0

Ok, low end hp.. not high end hp...NOS is high end
lol

Scott 89t2

talk to jimlab he'll help you out

otherwise nothing.

fuzzi

Make up for your lack of low end torque, in the high end... ie: Nos... and other mods that are good for n/a rx7's .. Such as the throttle body mod, or removing your standard clutch fan with and electric one... that will help it rev up quicker in first gear. Another thing you can do, and have done it with my parents minivan lofl. is to just hold the brake with your left foot, and press down the gas (while your in gear) and that will get your rev's up, to keep you closer to your powerband, and closer to your secondary injectors and sixports...

The Ace

Hey, no fair making fun of the N/A auto guys...

But seriously though, if you want low end, then yes, only a turbo can help you significantly (and a -God forbid- V8 )

HWO

4.5:1 LSD and forced induction

go_speed_go

You started out with 2 strikes against you - an automatic tranny & a convertible which weighs 350 lbs more that the coupe.

If you're serious about having more low end acceleration, dump the slush box. I know a guy who did it and it was a night & day difference. ALong with all the manual tranny & clutch stuff, you'll also need the the ECU and instrument cluster out of a 5 sp car to make your CC work correctly.

tmak26b

NOS helps low end, it increase torque, it reallly widens the powerband

SureShot

I'm supprised nobody has mentioned to check what Mazda did for low end torgue. The VDI and the 6-ports may be stuck. There are several threads that discuss them, just note if thay are talking about series 5.

SoulPyr0

6 ports ? and VDI how exactly to they work.. i mean like when your at a certian rpm... like i hold the brake down and press on the gas... but, it still does'nt get up like i would want it to.. i've heard that something about the 5th and 6th ports may be stuck... but, how do you get them un stuck.? or check to see if they are... and the VDI i know a little about them they are the little circular things near the exhaust on either side of the engine with a vac hose runing to them... if you blow in them and they come up and down, then they are working or something... i just wanna get more torque for my money... and i am afraid to use NOS on a stock engine... i dunno... i've tried cleaning stuff and what not but, not much works...

relvinnian

Sorry, that's completely inaccurate.

V8RX7com

People often think that the greater the horsepower results in greater speed. This leaves two things out of the equation. First, to reach the greater speed, the car must accelerate (requiring torque). Second, the velocity used to compute engine horsepower is engine rpm, not vehicle speed. A stock 89-91 13B rotary puts out a 160 HP but, it only puts out 140 pounds of torque. A convertible RX-7 weighs about 3,150 pounds, about the same as a Chevy Z28 Camaro, except a stock TPI Z28 has about 245 HP and it has a whooping 345 pounds of torque (almost 3 times the torque of a stock 13B). So to make a convertible rotary powered RX-7 “quick” is not as easy as a few bolt on modifications (I’m speaking from experience). The point I’m trying to make is, enjoy the RX-7 convertible for what it is (a cool topless under powered cruiser) or be prepared to spend a lot of money to make it “quick”

Coolidge

Torque is what you need when your car is a pig

Convertable curb weights(according to Mazda):
88 = 3003
89 = 3045
90 = 3045
91 = 3071

SureShot

OK - Here it is.
The VDI valve sits in the intake below the surge tank. If you look from the driver's side, you'll see it in between the primary runners. It's has a diaphragm that actuates the valve via a rod, much like the six-ports. The solenoid is controlled by the ECM, and is energized when the engine speed exceeds ~5000rpm.
The purpose of the VDI valve is to control the length of the runners. At low rpm, the valve is closed, which makes the runners long, improving low-end torque. At high rpm's, the valve opens, allowing a shorter path to the engine for a ram effect.
All NA fuel-injected Mazda rotaries since 1986 use an intake designed to improve power and torque by using the "shuttle effect" or "dynamic effect." This is the process whereby the intake air is forced into one chamber due to closing of the intake port on the opposite chamber (wave reversion). This effect was what made the difference between the 84/85 GSL-SE's 135hp and the 86-88 NA's 146 hp (in fact, the name of the intake on the 86-88 NA cars is DEI for Dynamic Effect Intake). 89-91 cars use the dynamic effect, too, but they use the VDI (for Variable Dynamic effect Intake) valve to tune the effect for two separate rpm ranges. This is why the series 5 engines feel much torquier (properly working models, of course) than their series 4 counterparts. In reality, peak torque only went up by 2 (138 to 140), but the average torque for a stock series 5 is much higher than a series 4, and low end torque is greatly improved, making an incredibly wide and flat (for a NA rotary, anyway) torque curve.

V8RX7com

Just remember…. he has an Automatic transmission which would make it even heavier. I’ve seen 3140 pounds as the weight of a stock 1991 RX-7 “Auto” convertible.