The Singh Slash

[turbovanman²]

Well it will be a chassis dyno and I'll use the same head, I will do is dyno it, then pull it off, groove it and redo it. It won't be the same day but it should be close enough to see the if there really is a difference.

[Frank]

Sorry, but the results you get wont be anywhere near enough to satisfy me or even Steve. I wouldnt even bother then. Not to mention, you need someone who can do real tunes to get the timing set, record knock data, etc.


Frank

[turbovanman²]

Sorry, but the results you get wont be anywhere near enough to satisfy me or even Steve. I wouldnt even bother then. Not to mention, you need someone who can do real tunes to get the timing set, record knock data, etc.


Frank

Thats actually pretty rude.

If you dyno it, move the timing around and redo it, the results will show something or nothing.

[automotivebreath]

Alternately try something like this.

Forget the dyno

Assuming you are modifying a turbo engine; raise the boost until is just
beginning to record knock retard. Pull the heads and groove (post a
picture of the heads for a recommended layout) Mill the heads to get
the identical combustion chamber volume pre groove. Reassemble and
raise the boost until you again record knock retard.

[turbovanman²]

This may sound dumb but why mill the head?

[automotivebreath]

If you cut grooves in the head you will be adding volume, this volume will
lower the compression ratio. If you assemble it with a lower compression
ratio some people will say it wasn't a true test because of the difference
in compression.

One more thing, if you mill the head it will affect the camshaft timing, this
will require attention also.

[turbovanman²]

If you cut grooves in the head you will be adding volume, this volume will
lower the compression ratio. If you assemble it with a lower compression
ratio some people will say it wasn't a true test because of the difference
in compression.

Ok, gotcha. I didn't think the grooves would make that much of a difference but I guess they do.

[automotivebreath]

It's important to realize that what you are considering is to provide
proof to other people that this works or doesn't work. If what you
provide revels benefits, the people that have doubts will quickly point
to deferences in the two tests.

[BadAssPerformance]

If you cut grooves in the head you will be adding volume, this volume will
lower the compression ratio. If you assemble it with a lower compression
ratio some people will say it wasn't a true test because of the difference
in compression.

One more thing, if you mill the head it will affect the camshaft timing, this
will require attention also.

Yep... lower volume... see post #65

http://www.turbo-mopar.com/forums/sh...6&postcount=65

[Frank]

Thats actually pretty rude.

If you dyno it, move the timing around and redo it, the results will show something or nothing.

How is that rude? You wanted to hear people's thoughts on dyno'ing, and for all the naysayers to be believers, that is what you have to do. Dont take it as an attack on you. I am just saying that if you are just going to simple dyno runs, it is not going to tell you much at all.

[Frank]

And that is the problem with the data from other's claimed gains over on the main Singh site (again not attacking the guys here on the board's gains). They mill the head alot more then just the groove's removed CC.


Frank

[turbovanman²]

Well, we'll see, I would still be up to do it, I could borrow my friends head ccing kit then machine it after the grooves are done. That also makes it alot more work than I thought as the head has to be stripped to get it machined,

[Frank]

That is the main reason why I dont thin alot of good data exists out there. I have been thinking of getting ahold of the Engine Masters Mag guy and getting him to defunk or prove it.


Frank

[BadAssPerformance]

Since it must be machined to match the volume of the slashes, not just milled cuz milling changed the quench, maybe an initial back to back would be fair enough. How much volume do the slashes add to the CC? If the slashes work better at a larger CC volume (Read: lower compression ratio) then they probably work better at the same CC volume.

[automotivebreath]

Since it must be machined to match the volume of the slashes, not just milled cuz milling changed the quench, maybe an initial back to back would be fair enough. How much volume do the slashes add to the CC? If the slashes work better at a larger CC volume (Read: lower compression ratio) then they probably work better at the same CC volume.

Milling the heads won't change the quench, milling the block deck, changing the piston pin location, rod length or reducing head gasket thickness would do that.

It would be best to cc the heads before the modification an again after to determine how much volume was added. SBC heads with one groove add 1cc.

My experience is the grooves work best with higher compression. 13.5:1 N/A races engines respond very well to this modification. I'm not familiar with turbo applications but I would expect great results at high boost.

[BadAssPerformance]

Sorry, guess I used the wrong term, I don't know too much about combustion dynamics. What I meant by different quench is that the distance between the piston top and the surface of the combustion chamber would be different therefore providing different mixture compression dynamics.

Interesting, if the grooves work best on 13.5:1 N/A race engines, I wonder how they would work on a 8.1:1 turbocharged engine.

[Directconnection]

One more thing, if you mill the head it will affect the camshaft timing, this
will require attention also.

Don't forget, you just added more quench which skews the results a tad as well.

I think some of this techno-mumbo-jumbo actually works where as some of it doesn't. Supposedly, some of this soft head science worked it's way into NASCAR at one point. Not sure if it's still in place or not. But, most people are splitting hairs trying this on a TD that is far out of tune. Exhaust the practical approaches before looking into scientific theories. Meaning... get everything out of the basics before trying to look elsewhere. Just like the noobs hooking up MSD boxes to stock T-II cars. True story analogy: years ago... back around 1988, I saw Michael Angelo the guitarist on a video instruction tape. The guy was fast, articulate, waaaay over the top, and a showman as well. Just did stuff way advanced and some stuff you ask why? He played guitar in the standard playing position. Then, switch hands and the picking hand becomes the frettig hand, and the fretting hand becomes the picking hand. Arms all crossed up and all... and playing 64th notes in a blurr and accurate. Then w/out missing a beat, would pick with the right hand again, and fret with the left, but upside down, meaning over the neck instead of under... then play passages alternating over then under without missing a note as well, back and forth. I started practicing this back in the day and was just getting a grasp on it. But one day I realized something.... instead of practicing an hour a day on the backwards playing thing, and instead, used that time to practice playing NORMAL... my NORMAL playing would get that much better. So, now I could focus on being 100% the best I could be, instead of 75% the best I could be with the remaining 25% a freak show move that gets old after 30 seconds.

[Directconnection]

Quench.. he's right..it stay the same. I was thinking extreme milling circumstances where the chmaber would decrease and be more quench like what some circle track guys have done. That section above the valves in the heart shape would not be recessed if enough material was milled.

[Directconnection]

Tony, This makes good sense to me. The tune up may need adjustment after
the modification but then we are getting away from a "grooves only" test.

Not at all. If it allows a more agressive state of tune, then that is job accomplished.


AB.... the busch results were done years ago. I have only been working at this shop for a tad less than a year now. I was told they did it on more than just one set of heads as well. Quite a few were their words. They owned a Busch south nascar team and wanted every advantage they could get.

[automotivebreath]

... Supposedly, some of this soft head science worked it's way into NASCAR at one point. Not sure if it's still in place or not. ....

Nascar, no they moved on, last I heard the use a concave dished piston.

The soft head concept is being used with air cooled engines, VWs and such
13:1 compression on pump gas. They call it super squishy pistons.

Guess what, they constantly argue, this guy says it's the best thing he ever
heard of, this other guy never tried it but says its bull. I read 10 pages of this
stuff last night, I'm still laughing. Go figure, 20 years later and they still can't
agree!