Technical piston ring advice

getting ready to have my rotating assembly balanced and I have to get rings, but not sure what style.
this will be a supercharged street driven drag car (think yahoo cup or drag week).
what style do you blower guys use , conventional or gapless? type of material?
this motor wont see over 7000 rpm or 12-14 lbs boost very often.
I have ross blower pistons 5/64 x 5/64 x 3/16 ring size.

 

I have about 20k miles on the blown 427 in my Drag Week car, it has normal size rings like that. I just use normal Sealed Power moly rings, nothing special, not even file to fit rings. goes over 1000 miles on a quart of oil, which is the best I've ever done with a big block.

Might open up the top gap a bit since you're planning on more than 8 psi boost.

 

Thanks Jim. I've read so much its mind boggling, so I thought I would ask here for real world experience from people doing what I want to do.

 

we don't worry about detonation and the top ring material? steel maybe a consideration?

 

I guess that depends on who "we" is. If you are building a street motor that you'll take racing occasionally, and it won't be running on the ragged edge, then no, you don't need to worry too much about detonation and the top ring material.

Keep the compression and boost reasonable, make sure it gets enough fuel and the timing is slightly conservative, and drive and run it.

works for me. ymmv

 

I would suggest checking out some ring gap charts from various manufacturers. Make sure you account for the added boost as Jim referenced. What did Ross recommend?
SPark

 

Boosted applications it is silly not to run a proper ring--cast rings will not cut it
Speed Pro plasma moly is ductile top ring--Total seal also makes that same ring package as do others--do not run gapless--they are for dirt track cars Total seal makes all kinds of conventional ring sets
I build engines for a living and no blown engine would leave the shop without a ductile top ring
These will all be file fit unless you ask for std rings You will still have to file top one some so your choice
Spent on the blower now do it right and get proper rings Ring makers tech line is the best bet

 

How many miles could a guy get on a set of cast rings in a blown street/strip engine, before they break? just curious.

 

Total seal recommended gapless top ring, I've never ran them before in any motor.

 

I guess you need to decide if you want to do everything you can with the motor, or do just what it needs.

 

I use Total Seal AP rings (steel top ring and napier second, if remember correctly) in my nitrous 489- no problems so far. This is in a Drag Week truck. The engine does not see more than 6500 RPM. I am building a 427 BBC for a street driven tow rig using your basic Sealed Power Moly rings. I guess it depends on your intention- sounds like you should go toward a better ring like the Total Seal. I don't use gapless- the tests I have seen show an improvement that is so small, I can't justify the price. One thought I have though is to check the ring gaps no matter what you buy. The moly rings for the 427 were supposed to be pregapped but the gap was all over the place. To match what the piston manufacturer said, I had to file all but 3 rings. Some as much as .008".

 

This is not an all out competion motor, but i would like to get a good set of rings.
I don't like the price of the gapless if another style will work just as good.