Inline 4 cylinder comp motor
 

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

Re: Inline 4 cylinder comp motor
 

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.

Re: Inline 4 cylinder comp motor
 

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...

Re: Inline 4 cylinder comp motor
 

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.

Re: Inline 4 cylinder comp motor
 

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.

Re: Inline 4 cylinder comp motor
 

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

Re: Inline 4 cylinder comp motor
 

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

Re: Inline 4 cylinder comp motor
 

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

By the way I was there a few weeks ago.

Re: Inline 4 cylinder comp motor
 

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.

Re: Inline 4 cylinder comp motor
 

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

Re: Inline 4 cylinder comp motor
 

Intakes with plenums required very shallow floors and a lot of work to make power,.[/QUOTE]

I run an Inline 6, and I'm trying an old Holman/Moody singel 4 .... Should I try to raise the floor of the plenum ???The engine is a destroked 300 (272ci) Ford

Re: Inline 4 comp motor - Quad 4?
 

Not trying to steal this thread, but years ago I was told that the Olds Quad-4 motors were not legal in Comp. Eliminator...

Can anybody explain why not??

Thanks!

Re: Inline 4 cylinder comp motor
 

I'm going to guess it was because it had 4 valves per cylinder, and the rules didn't provide for them when the Quad Four first came out

Today, 4-valve engines are allowed in L/A and F/D with a weight penalty. They are still not allowed in F/ED.

Re: Inline 4 cylinder comp motor
 

That's true, the norm in the flat-4 world is ubiquitous Weber 48IDA (and derivatives there of) I have a 146cu in flat-4 2-valve VW (with IR) that makes >2hp/cu in. Not bad for an antique 2 valve motor conceived in the 1930's with 11" pushrods!

But the debate in the VW world isn't a clean one either, I know of two racers who have experimented with a common plenum on a NA flat 4 similar to mine, he claims to have found more bottom end torque. The went moot, when the organization outlawed plenum manifolds in the normally aspirated heads-up classes, pretty much halting further development.

ProStock bike? IR

Another point of reference is the NA or 'All Motor' Honda guys that raced in NHRA's (now defunct) Sport Compact Series. Whaen I raced with those guys, I mostly saw (if not every one) individual runner intakes on the All Motor inline 4 cylinders.

Re: Inline 4 cylinder comp motor
 

Ask Aragona and you will know what it takes and what the issues are. LOL

Re: Inline 4 cylinder comp motor
 

The 4 banger VW Bug's around here use much bigger Webers, 58mm i think.

Re: Inline 4 cylinder comp motor
 

they are 55mm on top and 45 mm on the bottom there only one guy that can get them to run on a 4cyl

Re: Inline 4 cylinder comp motor
 

How about talking to Jake or Brett at Jenkins, .. aren't they responsible for Greco's 4 banger?

Curtis

Re: Inline 4 cylinder comp motor
 

Hey Curtis,

How big is Greco's 4-cylinder in L/AA?

Re: Inline 4 cylinder comp motor
 

I think around 200 cubes-it is a specially built block.