[Eric63M]

On my way to pick up my new block from the machine shop.

its a 383 lt1 (modern) with 11.88 compression. I'm shooting for 550 whp. the motor is a weekend warrior and will start to see a 125hp shot of nitrous later in the season. what would you set the ring gap at?

 

[Eric63M]

On my way to pick up my new block from the machine shop.

its a 383 lt1 (modern) with 11.88 compression. I'm shooting for 550 whp. the motor is a weekend warrior and will start to see a 125hp shot of nitrous later in the season. what would you set the ring gap at?

 

[ssimpala]

Pretty good info here: www.aa1car.com/library/ring_end_gap.htm

 

[vinniekq2]

dont forget to add for the NO2

 

[joelster]

dont forget to add for the NO2

You won't need to alter the ring gap if you are only planning a sub 200 shot. Once you get addicted to the sauce and want to put the big boy jets in, then ring gap becomes critical.

 

[Eric63M]

thanks for all the replies.

Joelster - for this season i'm limiting it to 125hp worth but next year its game on. I'll be competing in a LTX shootout and going into the power adder class and running 350 direct port shot. For this season its just going to stay at 125 and making sure i can get the power to the ground. Would you say gap for the 350 now or at the end of the season when i tear it down?

 

[Ripper 410]

I'd run plasma molys and set the gap .008- .010 top .009-.012 second

 

[327NUT]

This is a double post.........and .008-.010 top .009-.012 second???????????????? he's going to run nitrous!

 

[Ripper 410]

exactly he didn't ask for piston clearance he asked for ring gap and plasma molys can be run alittle tight

 

[68NovaSS]

IMHO, I second those gaps are too tight, especially for nitrous, and even a NA.

JE recommends:

Street turbo or nitrous, bore x .0050, bore x .0055 1st and 2nd rings and .015 oil. That's .020 and .022 for a 4.030 bore.

Nitrous race only even wider, .0070 and .0065 per inch of bore.

If you wanted tightening them up a bit, I would never go tighter than .0040 and .0045, top and second ring with NOS regardless of the ring material. Myself, I wouldn't deviate from the manufacturers recommendation.

 

[engineczar]

The merge is complete.

I'm on board with 68's recommendation unless the pistons are KB Hypereutectic's in which case you need even more gap on the top ring.

What type piston are you going with?

 

[Eric63M]

Thanks for the replies everyone.

68nova - I'll call the manufacturer today and see what they recommend.

engineczar - The pistons are forged JE -5cc flattops. then for the rest of the bottom end a Callies magnum XL crank and H beam rods.

 

[ap72]

I'd get a set of gapless from total seal. they work great and pick up a few hp. i run then in my more serious builds.

 

[joelster]

thanks for all the replies.

Joelster - for this season i'm limiting it to 125hp worth but next year its game on. I'll be competing in a LTX shootout and going into the power adder class and running 350 direct port shot. For this season its just going to stay at 125 and making sure i can get the power to the ground. Would you say gap for the 350 now or at the end of the season when i tear it down?

This shootout?????

^^my car is the camera car. Might not be a shootout next year. Run it N/A this year and I will see you in Mod N/A!

 

[Eric63M]

That is the shootout. Don't think this year is going to happen unfortinatly. After all the set backs and going extremely over budget on this build I'm not sure if it will be together in time, this is how its sitting so i still need to tune it massively, and dial in the rear suspension.

Next year for sure will be competing, this year if possible i will trailer it out and see. What is the index for mod N/A and any restrictions? I'm sitting with a S60, twin plate clutch, stage 4 t56, 10pt cage, and this engine i'm building. and only weigh in at 3085lbs with my last engine (without me) so 3300 with me in it roughly. Any fuel limitations?

btw your car sounds good, which cam do you have in there?

 

[cdminter59]

Here is JE's website. The ring gaps are listed in the tech corner. http://www.jepistons.com/PDFs/TechCorner/SCPDrawings/piston_instrc2618.pdf

 

[joelster]

That is the shootout. Don't think this year is going to happen unfortinatly. After all the set backs and going extremely over budget on this build I'm not sure if it will be together in time, this is how its sitting so i still need to tune it massively, and dial in the rear suspension.

Next year for sure will be competing, this year if possible i will trailer it out and see. What is the index for mod N/A and any restrictions? I'm sitting with a S60, twin plate clutch, stage 4 t56, 10pt cage, and this engine i'm building. and only weigh in at 3085lbs with my last engine (without me) so 3300 with me in it roughly. Any fuel limitations?

btw your car sounds good, which cam do you have in there?

Mod N/A is fairly open to whatever you want to do. There is no index. Run as fast as you can. It's heads up on a .400 pro-tree. The weight limit is 3075lbs WITH driver. Any race fuel you want to run, and aftermarket pcm. To be competitive you should be well into the 10's. Last years winner was running 10.29-10.40, but keep in mind it was 100 degrees out.

The full rules are right here:

LTX Modified N/A
Limited to quickest 32 qualifiers. Must have LT1-based engine. No power adders permitted. Heads must retain the factory 23 deg valve angle. Trick Flow 21 deg. heads permitted (PN TFS-30400008-M54). Converted intakes, stock and sheet metal permitted. 30" maximum height and 10" maximum tread width for bias-ply tires. W's limited to 28". 29.5 x 10.5 bias-ply permitted with 150 lb. weight penalty. Drag radials permitted. Non-stock style suspension permitted. Mini-tubbing permitted. Wheelie bars not permitted. Aftermarket EFI, LS1 PCM and carburetors permitted. Any GM transmission allowed. Lexan windshields not permitted. Independent rear suspension receives weight break of 200 lbs. Manual transmission receives weight break of 100 lbs. Minimum race-weight limit 3,075 lbs. Car and driver must meet NHRA certifications for the time the car is running.

 

[joelster]

My cam is a custom grind from LSM. Small base circle, altered firing order, solid roller.