burn slots in squish area ?

[HPaddict]

check this out what do you guys think?
SOMENDER-SINGH.com - Grooves 101

[Pinhead]

Read the In cylinder turbulence/burn rate thread. Or more specifically, this post in that thread.

[automotivebreath]

I did a lot of informal testing of this, bottom line - in most applications
results are very positive.

[Calypso]

No proven comparo here but...

Ispired by Automotivebreath good success I tried this on my 408W stroker with AFR205's 248/252@050 110LSA comp street Mech roller, 12.4CR, European 98RON pump gas (equals roughly US 93).
I run the engine with HOT air intake (coolest air to the motor was through radiator...) and too small intake carb combo (airgap/750demon). Headers are also 1-2 sizes small at 1 5/8", downpipes are 3" with X. Max timing was 36deg with slow ramp.

Sounds unhealthy, but worked neatly without any signs of detonation, even with more aggressive ignition ramps. Idles at 750 rpm, no issues on street. Already with this very compromized combo my '69 stang keeps up nicely with many motorcycles.

I'll run super vic with 1050 Ultra Dommy and good scoop and sized up headers next summer to see how it goes unplugged. Just wondering if I begin to see at least some detonation with the improved charge density of the unrestricted intake side, even with much colder intake temps working to my favor...

[Cammer]

I have reviewed all the groove literature available without finding proof of significant gains using this technology.

I have previously invited anyone to provide unbiased scientific evidence that these grooves are of any significant value. No takers!

Trust me when I say: if these grooves added anything big to an engine you would see them on all the new cars!

I advise members to concentrate on a good, matched combustion chamber/piston design.
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[automotivebreath]

Originally Posted by Cammer

...if these grooves added anything big to an engine you would see them on all the new cars!...

Cammer, for the most part my involvement has been using this idea to
enhance combustion on warmed over 50 year old combustion chamber
design, bottom line it works. As for newer designs, read what others are
saying about automobile manufacturers:

Originally Posted by Larry Widmer on SpeedTalk

When I was dealing with General Motors (mid 80's), I asked them why they
weren't willing to spend the additional $0.28 to increase engine efficiency 20%
, since most consumers would gladly pay a bit more for it.
I was told: "We dictate what the public buys".

Combine this sort of attitude with the fact that they assumed that investing
in more advertising (rather than long-term technology development).....and
that's exactly why they're in the shape they're in today.

[automotivebreath]

Originally Posted by Calypso

...I tried this on my 408W stroker with AFR205's 248/252@050 110LSA comp
street Mech roller, 12.4CR, European 98RON pump gas (equals roughly US 93)...

...Just wondering if I begin to see at least some detonation with the
improved charge density of the unrestricted intake side, even with much
colder intake temps working to my favor...

I don't have a feel for comparing European fuel to what we buy here in the
US. My guess is you will experience auto-ignition with the relatively small
cam and 12.4:1 compression.

[Calypso]

Did you look for just groove related publishings or directed squish jet information in general?

I just started here at this board and I do not have any intent to get into conflict with respected members, many of which have way more experience in racing engine development than I do. That said, I don't state any of my learnings as absolute truths, these are thing I have observed and concluded myself. I don't have the possibility or particular desire to scientifically prove them.

This is probably one of those areas where there are many ways to skin a cat. SAE 1999-01-3664 is about benefits of directed squish, Widmer's soft head does the same thing by playing with piston to head clearances, the Indian way to put the groove to the head is just one approach. All probably increase burn rate, completeness and reduce cyclic variability by adding turbulence or at least reducing turbulence randomness.

Speaking of the groove, I think it also helps at overlap when there is no burn going on. That can be explained at least theoretically. Any takers?

[automotivebreath]

Originally Posted by Calypso

...I think it also helps at overlap when there is no burn going on. That can be
explained at least theoretically. Any takers?

I have seen numerous occasions where engine idle was very poor due to a
long overlap period, one single groove in each squish area restored idle
quality. I believe this is a result of improved in cylinder conditions during
overlap. Perhaps the groove aimed between the valves lessened reversion
or could be in cylinder conditions were improved during the previous
combustion phase. I believe its the later.

[Cammer]

I acknowledge the value of non-traditional approaches to band-aid less than ideal engine components.

As much of my work has been done in research engineering I tend not to drift too far from the science.

All of these technologies can be argued from either side with a fair degree of success.

Your work appears to reinforce some degree of gain with grooves. None of my posts are to negate the work of another.

My shop is filled with failed projects. It is very difficult to design without some degree of failure.

A big problem in the research community is the lack of money for true research. If companies are not willing to experience failure they risk missing breakthroughs.

Members of this forum are willing to step outside the box and I applaud your efforts.
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