Chamber Grooves - what do you guys think?

[Ed Wright]

I know I'm really old, and evidently really dumb. I don't see how this is going to do much of anything good. Hope I'm wrong, more power and/or less fuel needed is always a good thing. Going to be interesting if nothing else. I participated in a test, as a favor to Pete Incaudo (Had to fly to Atlanta to do it), of Jim's golf ball dimples in an LS1 engine. Intake bowls, and piston tops. Was worth about 6 fwhp, and it changed the fueling up for sure. May be something here also. Old as I am, I haven't seen everything yet.

[automotive breath]

I don't see how this is going to do much of anything good. Hope I'm wrong, more power and/or less fuel needed is always a good thing. Going to be interesting if nothing else. ...

I’ve been doing this for more than a year. I have a good idea of what the results will show, but don't care to speculate. I'll let the numbers speak for themselves. This I will say, it's important to look beyond HP and torque.

[kdrolt]

I have a set of LT1 heads running with three grooves coming together with a common outlet between the valves. Comments please, before I show up at Larry’s for the test!

If the "logic" I posted in page 1 of this thread holds, then at a certain point adding multiple grooves will begin to defeat most of the effects of squish, and in doing so the jet velocity will drop to the point where it won't help assist burn. IOW you add grooves to help move the mixture from the squish region (good) but the jet speed drops (bad) and so does the useful squish (also bad). There's a tradeoff involved and I don't know where the optimum lies.

Still no word from Dr Combustion from Ford yet?

[V Remian]

If grooves swirling the incoming mixture are so efective-what happened to the mitubishi and honda jet valves?

[maxracesoftware]

The most amazing before / after test I ever did on the dyno was with a SBC, small hydraulic cam, about 370chp. It had a single plane intake with a Quadrajet carb. It was a used intake and came with an adapter that held in place a homemade plenum divider plate. The plenum divider plate was rectangular and didn't match the plenum at all, just very crudely divided the manifold plenum in half from front to back. We did all the testing with the divider plate in place but took it out for a couple tests to see what effect it had. The engine dropped 57ctq with the plate out. I couldn't believe it. That is not a typo - it dropped 57 corrected ft. lbs. torque!! I've tried a plenum divider plate on many other engines since and it has never had that much effect.

I don't know if the grooves mod will be that good

i've also witnessed a pretty weird effect
of a Plenum Divider when used on a Victor 4x4
on a NHRA SuperStock 283 with Rochester 4GC Carb.

that particular "top secret" carb spacer-plenum divider" combo
made a little over +20 HP gain on an already competitive well-tuned
and Dyno tested engine.

the only major problem=> weird ideling characteristics....
RPM would vary great deal like it was surging from a Vacuum Leak, yet
there was no vacuum leak.
you had to maintain engine RPM of 3000 RPM on upwards to make it go
dead-smooth.

since this RaceCar had a 6200 stall converter..i don't think it was
much of problem ??

i've tried normal Plenum Dividers in the past...but this particular one
was miles ahead in HP/TQ gains...must have been handling the very high velocity coming out of that real-restrictive 4GC Carb ,extremely well,
sort of like NASCAR restrictor-plate technology ?

in 1993 it ran (without that Divider)
i never found out what it ran WITH the DIVIDER in place ???

-----------------------------------------------------------------------------
NHRA SS/KA 1966 Chevy II Nova in Super Stock

283 cid ( 292 cid = 3.935 Bore x 3.000 Stroke )
Edelbrock Victor 4 x 4 with Rochester 4-GC carb
3-Step headers 1 5/8, 1 3/4 , 1 7/8 x 3.000 collector
Cam Motion Roller cam CM 123-02 74.3 deg OverLap
276.3 int / 280.3 exh duration at .050
.4087 int / .4191 exh Lobes
installed on 98.5 CL 1.60 int / 1.50 exh Rocker Ratios
3030 Lbs. weight 6.14:1 gears 1.96 1st gear PowerGlide
99.5 inch RollOut Slicks

February 14 , 1993 actual run
60 Ft= 1.420
660 Ft= 6.830
1320 Ft= 10.87 ET at 120.99 MPH

[Monkeywrench]

Just noticed the posts on the grooved combustion chambers. A USA-based BMW tuning shop, Metric Mechanics , has been putting multiple grooves in combustion chambers for a while now. They seem to be very succesful at it too.

http://www.metricmechanic.com/ , note the pictures I've seen from other publications of their work show deeper looking grooves, and only say 3 or 4 per combustion chamber, than the ones on their site. It may depened on the head application...

[Ape]

I might be wrong but Moto Gp bikes (supposedly) do have 3dimensional (3D curved areas) squish areas, for similar reasons. I know this doesnt fit the topic perfectly but nevertheless thought it might be off interest.

[automotive breath]

Just noticed the posts on the grooved combustion chambers. A USA-based BMW tuning shop, Metric Mechanics , has been putting multiple grooves in combustion chambers for a while now. They seem to be very succesful at it too…

Both ideas are based on the same principals, which are they induce higher turbulent flame velocity and aid in air/fuel mixing during combustion.

The results of higher turbulent flame velocity are less time needed to burn the mixture and higher flame temperatures. The results are lower ignition timing requirements and more complete burn.

The difference in the Metric concept and Somender Singh’s concept is the later has a greater potential because the squish flow is organized to generate the desired results. This compares closer to the work of Larry Widmer.

[airflowdevelop]

Let me know when you find the unicorns...I'll hang out then.

Forget about the dyno, run these things down the track!

point is..I have found many unicorns on the dyno...that turn into turds on the track.

You've got me interested...eventhough this tech-no-ology is older than Dick Cheney's gun powder.

[n2xlr8n]

This may elicit a grin from you guys (the folks testing this theory), but do you think the effects you are noting would as pronounced on a Hemispherical, DOHC 4V head?

Thanks for the input; I'm looking forward to seeing the results!

S.

[67RS502]

I talked to to my friend (a local roundy round engine builder here in Houston) and
he said things like this have been tried before... and his head porter Jimmy Bell didnt
think its gonna really work.
From following this thread I believe that some power will show up on the dyno.
But could this be do to the chamber design, or lack of on a 23deg. SBC head.
I think this could be a bandade fix that makes more power on a SBC, but the same
idea may not work on a hemi or 4valve head or a SB2 deal?

[Ed Wright]

Jimmy Bell didn't just fall off the turnip truck.

[MadBill]

I'm poised to start whittling on a pair of BBC heads in the near future, so results are of more than passing interest!
A philosophical point however: Although the 'squish jet' will be active only near TDC, the flame front (however 'wrinkled' by turbulence, etc.) will have been advancing for the preceding ~40 degrees of crank rotation. So is the plug gap really the appropriate target? (Perhaps that's the purpose of the multi-jet configuration: To churn up the advancing flame front wherever it may be at TDC?)

[Ed Wright]

The only way to know for absolutly certain would be to run the car at the track, pull the heads, cut them, put them back on and run it again. Hard to do all this at the track, unless you had an easy car to pull the heads (not a late model Firebird/Camaro, for sure) and John Force's mobile machine shop at the track. Unless it is a pretty good gain (or loss), testing on different days would probably be inconclusive.

I'm going to R&M's school this weekend (should know EVERYthing about building race engines by Sunday evening <jk>) and this may come up. Darren's take would be interesting. I think I know what it is from his earlier comment, but could make for some interesting discussion.

[Joe Mendelis]

Jimmy Bell didn't just fall off the turnip truck.

Is he the one that works at Faerman's?