Increasing Intake Flow Velocity - Suggestions?
 

I'm almost done modifying my carb to match the flow characteristics of a Sterling Nikki Carb, and was wondering what you all did to help the engine BEFORE THE CARB.

I removed the flapper in the stock air box and changed the filter, but does anyone have real world solutions to the largest restriction on my car? Matching intake flow to the openness of my exhaust is priority for me right now.

Thanks for the help. I've got a few mods in the works that might help too.

Stockport 12a
ISC Race Header (open for now)
Eventually a megaphone collector to 4" resonator to 4" hushpower. **Eventually**Tuning with o2 sensor to roughly 13.8afr @ WOT. 14.5-15.0 at cruising.
DLIDFIS Next.

I'll most likely end up doing a tolerance fit velocity stack with drop/clip secured in air filter. Similar to the Edelbrock mushroom filter designs. If I manufacturer some, anyone want one?

I put a turbo on mine. I think the increases the velocity ;)

Until you can tune the carb I would say the intake manifold is your next choke point to worry about. Its easy to screw things up though, not a rooky mod, you really need a flow bench to do it correctly.

My understanding of the smaller port size on the intake manifold vs. The engine is that it's designed for less reversion and higher velocity. So even if I get it to flow better, it could have negative effects as a PACKAGE to where I'm getting ugly turbulence or intake reversion.

Hmm, the dimpled idea which I've had saved for a while seems pretty interesting.

I'll figure something out. Thanks guys.

i think the stock air cleaner actually does ok up to about 170-180rwhp, i'm running a stock 12A air cleaner on my 12A, and the air cleaner is the limitation, but i'm still putting down 170-180rwhp@6500rpm.

with a stock nikki, the nikki is still the flow restriction

Yes! That's what I wanted to hear! Thank you, I'll fight like hell to reach your numbers and to continue to solve 30yr old mysteries, hahaha.

I think 150whp on a stockport 12a should be possible without a doubt. Especially with your DLIDFIS system to warm up my plugs a bit.

I have a Dellorto with a DLIDFIS setup (see my sig). It was measured on a dyno before I redid
the ignition from stock and before I swapped in the RB SP exhaust (was an older RE early
collected exhaust when dynoed). Any way to the point, at the rear wheels it dynoed at 134HP
and 124 torque. Add in losses and my stock 12A is probably right around 150HP at the flywheel
(est). New ignition and exhaust definitely moved the torque curve around but I've yet to redyno.

Hogged out Nikkis sound like a lot of fun, especially when those secondaries kick in.

Cut a hole in your hood and get a stack for your carb. LOL

Needs more hoodscoop! Although cold air isn't going to do you any favors if you're already running that lean. Jet tuning will make a big difference.

https://www.rx7club.com/attachment.p...1&d=1357955635

https://www.rx7club.com/attachment.p...1&d=1357955635

I mated the cheapo edelbrock filter to the carb using the rubber part of a *new* toilet plunger. I just cut the large side to fit the filter and the small side to fit the air horn and secured it with the bracket and wingnut that came with the filter. It sits just behind the hoodscoop. I never did make an airbox for the underside of the hood, which would have made this even more effective.

My carb has about the same mods as a Sterling, including bored venturis. The stock intake manifold is mildly ported and dimpled with the shutter valve removed.

150 crank horsepower is possible on a stock port. 150whp is only possible on a seriously bent dyno. For reference, I've had an engine that pushed my car to high 13 second quarter mile times make about 150whp...

The biggest restriction is the carburetor itself, then the ports. Not the intake manifold, not the air cleaner...

I'm not 100% sure but I think the stock carb flows 330 cfm and the stock intake flows 250 to 280 cfm on an 85 car. The exact stats were on sterlings website if its still up. So as far as numbers go the stock intake is more of a restriction than the stock carb. Sterling was supposed to be working on making a hi flow intake for his carbs but with the circumstances surrounding him I doubt we will see the intake or anymore of his carbs at least for a long while.

Yeah I think a short velocity stack that's tolerance fit to the 4" OD carb mouth with a drop in filter would be great.

Simple, cheap, effective. Check out BPi for velocity stacks if you're interested.