Gas porting without vac pump?

[KnightEngines]

I build for a very restricted road race class over here, 208 cubic inch inline 6's, restricted to a single throat Stromberg carb.
They make around 180hp - that's a real good one.
Racing is very, very close, 5hp is a lot in this class.

We've just about exhausted all the avenues to screw more out of these things, the only thing we haven't played with is ring drag - mostly due to being limited in piston choice to slugs that take fat rings.
Vac pumps are not permitted, even a Vac-u-pan is out.

Anything we do with the rings will pretty much have to be a custom order - engines run a 3.685" bore. We'd also have to use a ring spacer to run a thinner ring & we couldn't use vertical gas ports (sealer would see them).
So we'd be limited to lateral gas ports & thin rings in wide grooves with spacers.

So, what I'd really like to know before we spend the $ on getting rings & spacers made is whether we're likely to see any gains with thinner, low tension rings & lateral gas ports, along with finer bore finish & lower tension oil & second rings.

[bigjoe1]

Based on some testing I just completed.there are some big gains from an 043, 043 and 3.0 ring pack.The one thing I do not know is about the ring groove spacers. It is also very important to get the rings back cut ( smaller radial width ) as much as possible to reduce ring tension. Talk to Keith Jones at Total t anything is better than nothing


JOE SHERMAN RACING

[engineczar]

http://www.competitionplus.com/index.ph ... -stockers-

[DCal]

Basically, you are talking a combo that almost all NHRA stock eliminator racers are using i.e. a thin ring (1.2mm) and an.030 spacer. Total Seal has a spacer with lateral gas ports milled into it. I would use the lateral gas ports if rules allow. Depth of the ring groove would be determined by the spacer radial wall plus .005 clearance just in case the piston manufacturer uses a generous radius on the ring groove tool.

[KnightEngines]

Thanks guys, food for thought!
Those gas ported spacers on the total seal site are very, very interesting, we could get that past a sealer no problem at all, nothing in the rules says anything about the rings themselves or how many must be in each groove.

Time to talk with total seal I think, anyone I should speak to there about this?

[bigjoe1]

Keith Jones- Tell him I sent you


JOE SHERMAN RACING

[KnightEngines]

Thanks Joe!

[twl]

Napier cut 2nd ring.
Big reduction in ring friction, and better oil control.
Cheap and easy. Total Seal will do a Napier cut on your 2nd ring for around $20 each.

Set your oil ring tension as low as you can get away with, by adjusting the ends of the expander ring to expand only the tension you want. Most ring friction is on the oil ring.

If you do a good job with oil ring tension, and use a Napier cut 2nd ring, you have a good portion of it licked.