Inline 4 cylinder comp motor

[RJ]

For those that run them, what is the biggest issue facing a inline 4 cylinder comp motor? - vibration?, spread between intake cycles?

I see some with IR setups?, and some with plenums?

Thanks

[art leong]

Originally Posted by RJ

For those that run them, what is the biggest issue facing a inline 4 cylinder comp motor? - vibration?, spread between intake cycles?

I see some with IR setups?, and some with plenums?

Thanks

I've been searching the same subjects. And It seems like Individual runner/throttle body. seems to be a little better in the torque department, while not giving up horsepower.

[Charlie Yannetti]

If I had any questions about 4 cylinder Comp motors, I would be giving Al Ackerman a call... and if you have been watching D1 Comp this season, you would have noticed that he and Dave Ring have tried a couple of different induction systems...

[david ring]

The induction you'd use would depend on the class, econo classes are running carbs and usually a plenum. But Ambrose and Huettman in their inline six went to a couple of throttle bodies and a plenum this year as well-they had good success. We are still experimenting with that setup and Al would be able to tell you much more next year to be quite honest.

[CycloneFE]

RJ,

If you like to think outside the box, look into inboard powerboat racing. There are a lot of 1Liter, 1.5Liter and 2.5Liter racers that are doing some amazing things with inline 4 cylinders. Some are unlimited classes and OMG!!!!

I can imagine some with trannys behind them and in the rails of an alterd screaming down a quarter of a mile instead of bouncing on the water. Most of the boat guys are great to talk with.

[rod]

many years back, norwin plamer from manhattan ks, had two good inline 4 cys, won NHRA world comp. with a datsun inline 6 as i remember. his biggest problem, at that time, was vibration. he used 2 holley 500 CFM 2 V carbs. and the fule would bounce out of the vent tubes!!!! today with better computer generated cams and digital balancer machines, and possibly even a good air flow bench, some of that could be solved.
the first car was really something to see. many hours of thinking.
rod

[art leong]

Originally Posted by rod

many years back, norwin plamer from manhattan ks, had two good inline 4 cys, won NHRA world comp. with a datsun inline 6 as i remember. his biggest problem, at that time, was vibration. he used 2 holley 500 CFM 2 V carbs. and the fule would bounce out of the vent tubes!!!! today with better computer generated cams and digital balancer machines, and possibly even a good air flow bench, some of that could be solved.
the first car was really something to see. many hours of thinking.
rod

Innovators West will custom make a SFI damper for just about any application. They are making one for me now.

[rayfin]

http://www.kansasracingproducts.com/...s/Welcome.html

By the way I was there a few weeks ago.

[SSDiv6]

Originally Posted by RJ

For those that run them, what is the biggest issue facing a inline 4 cylinder comp motor? - vibration?, spread between intake cycles?

I see some with IR setups?, and some with plenums?

Thanks

Due to reversion at the higher RPM ranges, caused during the overlap event as it takes place on inline 4-Cylinder engines, the IR setup is more suited to making power when compared to a plenum. I cannot find all the data I accumulated in the past; many years ago, however, the reversion issue was a detriment for power to the extent I could see atomized fuel coming out the stacks of the Weber carburetors at high RPM.

Intakes with plenums required very shallow floors and a lot of work to make power, however, they did not make the power of an IR setup. Also, the lenght of the intake is very important. We built intakes with an aluminum base for the engine and another for the carburetors. For runners, we used hose for Turbo applications with clamps at each end so we could change the runner length easier.

[Bench Racer]

I am sure the inline 4's are a different animal than the aircooled VW's but the standard for the vw drag engines is the 48 ida's. with IR induction. There are several different performance manifolds options for the Bug engine that utilize a single carb ranging from a 2bbl, or a 4bbl setup. The single carb performance setup on a bug is normally only seen on a mild street car or in a racing class where rules call for stock carburation. I know a lot of the trends in car performance is spread by the monkey see monkey do thing, but when it comes to the quickest n/a aircooled VW's it will have 48 IDA's and IR manifolds. Don Jackson