kylejohnston1

Good comments. I should mention I purchased the Vitesse MAF kit at a heavy discount several years ago from someone locally who was returning their car to stock prior to selling. While the Vitesse kit has been great, I likely would have considered the options above had the used MAF kit not been available.

revolve40

I spoke with Sharkwerks about their standalone kit and was told they really need to have the car locally to tune the software. I suspect they'd let me buy a kit, but were also up front about the nuances from car to car which was appreciated.

Kappi2907

Should be more easy to use a MAP sensor like modern cars do.
MAF is old technology.

chuckoslovakia

I agree. A standalone ECU with modern load sensors and a wide-band o2 sensor for closed loop lambda control would be a great way to improve this car. Looks like there's plenty of kits that do this now.

Odin

I have the FVD LB2-300 Race kit on my C4. It really elevates the car and complements the LWFW, RS clutch, cup exhaust and 100-cell sport cat. PSS10 and strut bar for road holding. Max rpm is raised from 6800 to 7200rpm and alongside the cam coming on at 4500 you get an extra prominent rush of power at 6000rpm like the champagne cork popping, all the way to 7200rpm. Best thing is when running a 30/70 mix of E85/V-Power98 which makes for an additional 50hp according to the butt dyno. Depression sets in when the E85 runs out on the next tank of normal fuel.

Kappi2907

Did you install the upgrades the same time?
Changing the rev limit is not good.

TexasPorschelover

OK here’s the latest. We discovered a couple problems. First the number three cylinder intake valve spring was broken. The valve is straight and unbent luckily. A number of the valves were out of adjustment too. Second the fuel injectors which were supposedly Bosch GEN threes may have been Chinese copies. They are pretty new injectors and we’re disintegrating. Luckily I had the original injectors and had them overhauled and flow tested. The rough idle started with the install of the FVD kit but may have simply exposed other issues. We will know soon.

revolve40

I fixed several vacuum leaks, installed a new ICV (I think mine was fine), installed a new vacuum check valve, and put ethanol-free 93 in and tried again.

The car started on the first try now (wouldn’t before), but I still needed to give light throttle input to raise cold idle for a few minutes.

It would pull strong from 4K to redline, but I could still hear some pinging (not as bad as before) and the warm idle was now about 1200 vs. 900 before.

I think with a bit more patience, one could dial in the kit to work very well. Particularly if you wanted to run octane booster or opt for a lower-octane ignition map.

My experience with FVD has been nothing but positive. They have offered solutions and have essentially guaranteed my satisfaction through a generous return window. While this kit isn’t for me, it does “work”; it just needs some fine tuning and patience.

My final comment is that it’s entirely possible (and maybe even likely) that the kit did not perform to expectations purely based on the nuances of my particular vehicle.

TexasPorschelover

Update. As mentioned before there was some issues that were not known but now corrected. First, a broken spring on #3 cylinder. Second, found a vacuum leak and corrected. Third, valves badly out of adjustment, corrected, Fourth, clutch installed backwards - Corrected with new and a bunch of parts updating clutch actuation etc. Fifth, spark plug wires replaced, WOSP alternator installed and converted to single belt RS type pulley. So the results have been pretty terrific. There was to many little "while your in there's" to list also. Power is way up, idle is good and stable etc. The FVD intake was not the issue - it was a bunch of little things and one serious one (broken valve spring). I pretty happy with this expensive exercise and the car certainly is improved as a result and certainly deserving of the cost.

revolve40

Great to hear - I came to the conclusion that the MAF is much more sensitive to minor issues such as vacuum leaks than is the AFM which compensates for them. Glad you got it sorted and are happy.

fast951

Based on my experience, both AFM and MAF are affected by vacuum leaks. A vacuum leak causes unmetered air to enter the engine, therefore the fuel and ignition calculations by the DME are off.

Would you elaborate on how "the AFM compensates for vacuum leaks"?

revolve40

I don’t know that to be true and I suppose I should have just left it at “the MAF is likely more sensitive to vacuum leaks”.

fast951

E85 requires about 35% more volume to get you the same AFRs as regular (non E fuel). By mixing 30% E85 you run lean. E85 raises the fuel octane.
This tells me (A) your ignition is advanced for pump gas (possible knock, DME reduces timing to compensate and reduces power).. Adding E85 raises the fuel octane, so it's possible it eliminates or reduces knock so the DME does not pull timing (via knock control). I want the ability to monitor knock!

(B) When mixing E85 you run lean unless you can enrich the mixture. However if your can is running rich to start with, the E85 will bring AFRs close to where you want them. Running lean causes all sort of issues under load.

Your tune is off for the fuel you are running.

To monitor knock, take a look at V-Knock inexpensive insurance.

fast951

Both are sensitive to vacuum leaks.

fast951

Most Vitesse 964 MAF kits we sold since 2007 are still in the field. Glad you are enjoying your Vitesse MAF kit.