JM993

[QUOTE=TheOtherEric;6171616]I've wondered if there isn't a simpler zero-tool way of checking for vacuum leaks.QUOTE]

I used my mitivac.

Steve Weiner-Rennsport Systems

IMHO, there are two effective way to detect and source vacuum leaks in an intake system: using a smoke machine made expressly for this purpose or judicious use of carb cleaner introduced at any juncture, hose, or connection in the intake system. This latter method requires some experience to get effective results.

nile13

Steve, while we have you here... Do you think that bumping idle speed or some remapping of ECU around the idle would be able to aleviate the stalling issue? Or is this futile? I understand that vacuum check and leak repairs come first.

nsully

I recently installed a LWF in my 97. No stalling issues, and much better drivability.
The quick throttle response simplifies starts. I would not go back.
At the same time, so I don't really know if this had a specific effect on the LWF, I had my ECU remapped by Steve W. My car feels like it has a significant power increase through every gear. Good clean fun! This is a combination that I can fully recommend. I would urge anyone with a 97/98 to consider this upgrade.
Neil

Steve Weiner-Rennsport Systems

Both changes certainly do help, but none of these measures makes the '95 cars absolutely perfectly well behaved. There are simply too many different variables at work.

In my experience, applying all of these measures (preceded by the engine mechanicals), combined with a driver technique change, makes the LWF livable and enjoyable for those individuals wishing for a more lively engine and snappier throttle response.

I'd be the first to tell a prospective customer that this modification is not for everyone (and I do!). I've had to remove 2 of them when a spouse couldn't get the hang of it, but I've also had several 95's that were perfectly well mannered with LWF kit installed and no stalling issues.

The OBD-II cars ('96-'98) have been seamless unless there were resident issues.

nile13

The next question that comes to mind - how hard would it be to convert to OBD2? The recall harness, supposedly, is th same and that's what most of us already have in the car. Putting OBD2 ECU in... what signals would it be missing? Varioram comes to mind. It could possibly be fooled by some constant signal. Anything else? Immobilizer could make it a non-starter.

Steve Weiner-Rennsport Systems

Converting an OBD-I car to a fully functional OBD-II one is NOT for the faint of heart or wallet.

Its not a small job since the whole car's harness & ECU is different as well as all the different things that are monitored.

That said, its doable provided that someone has sufficient resources to do everything properly.

TheOtherEric

I had my chip tuned to bump idle up. At 1050 to 1100 rpm, I don't think it ever stalled but an idle that high is *annoying*! No way. So bring it back down to an acceptable level like 950 like I did, and your stalling comes back every so often.

Unlike some, I didn't notice a huge performance difference when I installed the LWFW. I don't see why all the excitement, honestly. But I'd still probably do it again unless it was a pure street car.

mcpiaseczny

I completely agree. Has anyone measured torque/hp at the wheels before and after a LWF conversion?

I believe that nearly all of the benefit is in improved shift times, and there is practically no improvement in actual car acceleration aside from that.

fast_freddy

My wrench, who is an accomplished SCCA racer "thinks" that it is worth 1/2 second a lap on the track. It is "unsprung weight" so it really isn't any different than using light wheels, tires, etc..

mcpiaseczny

The flywheel is sprung weight. Unsprung weight refers to the bits of the car between the road and up to and including the suspension - basically, all of the things that move when you hit a speed bump. Mass in that area affects a cars handling because it decreases the rate at which those parts (specifically the wheels+tires) can move and adapt to the road.

I don't have the math in front of me but I could be convinced that between the reduced mass and quicker shifts a LWF is worth a 1/2 second on a given track. I just don't think there is enough of a difference there to be noticeable to the driver while accelerating.

TheOtherEric

What your wrench meant to say is that LWF has less rotational inertia, which (along with the car's mass) resists your car accelerating. Compare this to the rest of your rotational inertia (i.e. rotors, wheels, etc.) and I bet you'll find it's pretty small. 1/2 second a lap? I'd be really surprised. I'd guess maybe .1 or .2, but that's just a guess based on how different it feels to me.

fast_freddy

Technically, you are correct (yes were are speaking technically, I know that). Perhaps a better analogy/term would have been appropriate. Being a former competitive cyclist we were always concerned with the mass that rotated and tried to reduce that weight. The weight of the frame, seat, handlebars, brakes, etc. were insignificant relative to the weight you rotated such as the wheels, pedals, cranks, cogset, chain, etc. I'm sort of extrapolating those applications and benefits of a bicycle into a car.The flywheel is a drag on power, plain and simple. The parasitic effects exist, just like the A/C, drivetrain, etc. Really no different than the ill effects of heavy wheels.

mcpiaseczny

I totally agree, but I doubt that on cars the effect of a LWF is that drastic, hence I'm curious about whether anyone has measured the torque or hp delta with anything other than their gut or butt

964sepp

to make it clear: a LWF has no influence on power or torque, it just reduces the (rotatory) mass, the engine has to accellerate. Lighter wheels will show the same effect