Just got my 96 mm AA P&C kit for my short stroke 66 mm motor that I'm building. After doing research, I'm looking at the 86a Web Cam as I've always been a higher-end power and don't care much about torque. Using 1.8 heads, opened up with bigger valves (dual springs too), 40 IDFs and POSSIBLY ceramic coating the tops of the pistons and combustion chambers and running 9.5:1 CR.

Question - Since the 86a is a top-end happy cam, should I match it with shorter intakes or stay with the longer intakes to help balance it? Pros/cons? I'm not worried about in-town drivability and would rather it be spirited on backroads and at auto-x's.

Thanks for your input!

Randy

I don't think you'll be going high enough in revs for short manifolds to be beneficial.
The highest I've run an engine with an 86a cam is 6500rpm.

For auti-x I think you'd be better off with more torque than high rev power. Maybe a Webcam 494 would be better. It's higher torque plus improved power throughout it's range. At least that's the cam I'm thinking about for a 1911cc motor with standard intake manifolds. What size valves are you going up to in your 1.8 heads? Anyone else have other suggestions?

Thank you!

OK, my machinist also votes for the longer manifolds too.

Auto-X'ing will be a one to two event per year occurrence, so it's not the main focus here. I've auto-x'd three times in my life, and have driven on DE event at Thunderhill. :-) Love racing, but other hobbies come first.

Appreciate your input!

@ Chris - So you've heard good things about the 86a? I haven't found a lot of info.

@ Lonewolf - 1.8 heads with 2.0 valves (42/36).

I was using one in a 1.8L race car engine for a few years.
I liked it.

I started with stock 1.8L heads and 9:1 compression.
It was done making power by 6000 rpm.
Seat of the pants dyno said about 100 hp at the crank.

When I had some funds I had a set of heads prepped with ss valves, hd springs, and port work, and I upped the compr. to 10.5:1.
I think that made about 120 whp on a Dynojet with a redline of 6500.
Driveability at low rpm didn't suffer too much either.

That's exactly what I wanted to hear as that's a similar direction I'm taking with my motor and heads. Closer to 10:1 with the 2.0 valves, some port work and potentially ceramic coating the tops of the pistons and combustion chambers.

Assuming you were running an oil cooler at the front of the car with that setup, right?

I already had the front mounted cooler but I would have been fine with just a rear mounted cooler.

That combo will benefit immensely from a proper exhaust system.

I bet it would!

That's out of my budget right now, plus I needs da heat as it's likely to be a DD when I'm working on other cars in the stable. Trust me though, I spent a lot of time drooling over the exhausts when I was at your site to get the SS fuel line / pump kit.

Oh geez Chris, you do offer heat exchangers... It's going to have to wait, but they'll be on my wish list.

Oh geez Chris, you do offer heat exchangers... It's going to have to wait, but they'll be on my wish list.