performance question

[scirocco81 at vwmail.net (Eric S)]

Before changing your fuel system, might I suggest getting a cam first?

CIS Lambda (what your 81 has stock) is typically known good to around 150hp or so....thats why I don't think you should be looking at changing fuel just yet...I doubt its the real problem here, unless you are seeing it run lean at high RPM with a air/fuel guage or on a dyno with a exhaust gas analyizer.

The stock VW cams are tuned for low end torque and driveability, you will see that you really don't have much power in the high rpms and an unwillingness to rev quickly.

Getting a more agressive cam should give you a bump in power in the higher rpms, better revability, with a loss in bottom end torque.

Just recently, I jammed a Kent 278 cam into my completely stock JH engine.  Driveability was slightly affected, and there was a decrease in bottom end torque (this is all from the butt dyno, personal impressions).  However, the car has a nice jump in power from 3-4k and pulls cleanly right past red line, no problems with good high RPM power.  No changes to fuel system, timing, igntion, nothing, just a cam.  The motor would choke out around 5k rpm before and had little power up there anyway before the cam.

--
Eric
www.VintageWatercooleds.com

79 VW Iltis
81 Scirocco S (*TDI* swap and complete restoration in holding pattern)
81 Rabbit Truck LX Diesel (Waiting for BAE Turbo Install)
83 Scirocco Wolfsburg
91 Cabriolet (2.0 Crossflow 8v swap and mechanical rebuild in progress)


--- Carpenter/Graffy <egraffy@earthlink.net> wrote:
>Hi All,
>Just came back from autocrossing the 81 at Blackhawk Farms Raceway, and 
>learned enough about the car to post a couple of performance questions. In 
>addition to the fact that I neglected to put high-temp brake fluid in the 
>car and felt my brakes turn to mush within the first few practice laps, I 
>seemed to be giving away a lot of high-end performance in the straights 
>(compared to the third-place Integra, second-place Taurus and first-place 
>Sterling. I have a stock RD (1.8L 8V) engine in the car with a new 
>Techtonics exhaust, but have retained the original 81 ignition system, 
>intake plumbing, fuel distributor, and injectors. I suspect that I'm 
>hindered by not getting the right air/fuel flow at the top end, with 
>perhaps a corresponding lack of ignition precision. My questions are:
>- If I want to maximize these elements for this motor, do I need to convert 
>to a complete CIS-E fuel/intake/ignition system, or can I just replace 
>stuff piecemeal, like the fuel distributor with a different regular CIS one?
>- Should I replace the injectors with the later "air bleed" ones?
>- And if I do that, should I also graft in the intake plumbing from a later 
>car to provide the air bleed to those injectors (yes I know it only really 
>matters at high manifold vacuum and low RPMs)?
>- Which ignition?
>Thanks,
>Cris
>
>
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