Steve Wong, AFM, & MAF

[JV44HeinzBar]

Hi,
Well, I'm well into my 964 mania now that I've secured the right car. I've been reading some of the posts on Rennlist, and to be honest, I don't have a clue which direction to go in. I'm more curious now than when I started.

I've seen on some of the post from Rennlist that these mods can add anywhere between 30hp - 50hp gains.

I've also seen threads about rebuilding to 3.8, which out of the question now, but an interesting side note to the 3.8 build was that installation of "cam" only mods. Thoughts?

Oh well, any PPheads in here that have done the SW, AFM, or MAR mods? If so:

1. Type?
2. Brand name?
3. Result?
4. new HP ratings if any?
5. Problems?
6. Cost?

I'm probably getting in over my head as I haven't even taken possession of the car yet, but I'm fired up on the idea of modding the car for more performance w/o spending a tremendous amount of money, e.g. engine mod/rebuild.

HB

[JordanPryce]

horsepower costs money.

The thing about the 964 is that it really rewards good driving. I wouldn't spend a dime on upgrades until you decide if you really need them.

I enjoy driving the 964 more than I ever did my 408hp 997 GTS

[Beetle88]

I agree with Jordan. The 964 is such a wonderful beast out of the box that even in stock form, you'll be a able to drive it like you stole it!

A lightened flywheel, Steve Wong chip and a cup bypass may increase your awareness to the car, but even those subtle mods are more than enough.

Cheers,

[ischmitz]

Changing to an open exhaust (993 headers) and a chip is what probably gives you the most "bang for the buck" if you want to modify things. The light flywheel could cause drivability issues (stalling) - not sure that it really makes sense.

Then there is always making the car lighter (stripping interior parts) if you really need better power/weight ratio.

Ingo

[Beetle88]

Wong Chip can address the stalling issue with the lightened flywheel.

Cheers,

[porterdog]

I don't think I've seen legitimate evidence that the stock AFM is a bottleneck.

[clutch-monkey]

Originally Posted by ischmitz

Changing to an open exhaust (993 headers) and a chip is what probably gives you the most "bang for the buck" if you want to modify things. The light flywheel could cause drivability issues (stalling) - not sure that it really makes sense.

Then there is always making the car lighter (stripping interior parts) if you really need better power/weight ratio.

Ingo

lightweight flywheel is one of the best bang for buck mods, do it while you're changing clutch etc.
as above SW chip prevents it from stalling.
picked up 19rwkw with better exhaust and a lightweight flywheel on a similar car

[Bill Verburg]

Originally Posted by porterdog

I don't think I've seen legitimate evidence that the stock AFM is a bottleneck.

Compare late 964 plastic intake engine to 993 early plastic intake engine
cams pretty much the same, main difference is ramps to accommodate hyd lifters
valves same, 993 has 8mm stems 964 9mm stems
ports 993 1.5mm larger intake & 1mm larger exhaust
CR same
metering 964 barn door mechanical, 993 hit wire electronic
exhaust 964 crossover, 993 dual

hp 964 250@6100, 993 272@6100
torque 964 228@4800, 993 242@5000

You can see that they went to a lot of trouble to open up the intake/exhaust flow path. while there is no # that separates out the metering it certainly contributes to improved flow

[porterdog]

No doubt, but if swapping the stock afm in a 964 released power people would be all over it; the newest of these cars is 20 years old and the 'easy' mods have all been explored. The fact that every 964 owner isn't clamoring for an AFM replacement suggests that in the absence of broader changes there's not much to be gained by this single modification.

OP: Get yourself a g-pipe and drill your airbox lid

[LouZ]

I have an Autothority hot wire MAF and K&N filter which replaced the barn-door. Unfortunately, this setup will not work with a stock Steve Wong chip.

I can't quantify any improvement due to the intake swap. I have a dyno measured gain of 18 HP and 18 pound-feet of torque, however this included the inlet, Fabspeed dual exhaust and cam timing changes.

[JV44HeinzBar]

I don't know if you guys have searched Rennlist forums, but there is a great debate on this issue. I wanted to get an opinion from this site because I've been coming to PP for some time now.

HB

[Shamus911]

On a stock 964 I think the bang for the buck mods for acceleration are:

- Freer flowing exhaust - best case being a full header exhaust, the stock 964 headers don't flow very well.
- Drilled airbox - nearly free and 2-3 hp (plus the intake sound when the flap opens is glorious)
- LWFW and Chip - I felt it was a pretty dramatic difference in overall feel of the car, and a chip is required
- Gears - big difference in acceleration when you stay in the power curve with every shift
- Motec upgrade - expensive but big power increase relative to everything else

Just my 2 cents worth!

[ischmitz]

See here 'No Bad Days' performance chip - first impressions for what a chip can do on a 964: 17HP. It is a direct comparison. The data was taken on the same day, same dyno back-to-back with the switch in stock position and then in chip position.

The car had B&B headers (better flowing than stock exhaust) but no other major modifications.