Bottom end question

**bachert24** · 06-06-2015

Dropping off my L36 at the machine shop pretty soon to get it cleaned up before I rebuild it. I'm planning on throwing a bunch of N/A power goodies at it (I know supercharger is better, but that's not what I'm doing) so I'm wondering what I should do with the bottom end. I'm assuming the crank is plenty strong enough so I'm wondering what I should do with the pistons and rods. I can't afford diamond and I'm certain they are overkill anyways. I'm expecting about 300-350 hp at the crank. I thought I read that I could L26 rods and L67 pistons but im afraid the stroke would be off without knowing the measurements. You guys have any real world advice? If note: I cleaned up the combustion chambers on my heads so with the metal removed I am losing some compression. I would like to be around 10-10.5:1 so I can run 87 octane still. My head gaskets are cometic .051 gaskets. Let me know what y'all think.

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**Scottydoggs** · 06-07-2015

best advice is to not bother. last guy who modded up a n/a engine was rather upset at the dyno.

leave the bottom end alone, buy a turbo. or do nothing, cause the gains are not worth the cost modding a n/a engine.

**Turbocharged400sbc** · 06-07-2015

the only NA setup that would be worth putting the time and # into would be a real high compression domed piston (custom pistons) setup with a big shot of spray for when 250-300ish crank hp isnt good enough fer ya and you want some actual power.

the cam that'll give you that kinda power up top is gonna make it drive like **** at lower rpm's.

**bachert24** · 06-07-2015

I have a GT1 cam, porting everything. Ill be getting a tune. I'm not expecting to set records, just want more of a kick in the seat. 350 crank hp is very achievable N/A. Again I'm not looking for opinions on what not to do with my car, just the rods and pistons. I'll likely add a turbo down the road, but it'll be a few years as I'm raising 4 daughters.

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**Scottydoggs** · 06-07-2015

you'll never get that much hp just n/a.

**bachert24** · 06-07-2015

Originally Posted by ScottyBDoggs

you'll never get that much hp just n/a.

Wrong. But thanks for your opinion.

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**Scottydoggs** · 06-07-2015

not wrong, but good luck with it. its missing 2 pistons for your math to work.

**chrsmi1** · 06-07-2015

Gotta go with scotty. I believe on club gp they have a thread where the n/a dyno record is like 250. Which would only be like 320 ish on a good day crank.

**chrsmi1** · 06-07-2015

http://www.pontiacbonnevilleclub.com...opic38121.html

http://www.3800pro.com/forum/natural...-n-record.html

**Turbocharged400sbc** · 06-07-2015

Originally Posted by bachert24

I have a GT1 cam, porting everything. Ill be getting a tune. I'm not expecting to set records, just want more of a kick in the seat. 350 crank hp is very achievable N/A. Again I'm not looking for opinions on what not to do with my car, just the rods and pistons. I'll likely add a turbo down the road, but it'll be a few years as I'm raising 4 daughters.

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JE wanted 900 for dome 3800 pistons and they already make OE dish pistons so they have the file/programs.

youd have to mill the **** out of the heads and remove all the MLS layers aside from the top and bottom to get close to a high compression ratio with any oe dish or aftermarket dished piston and that's at 0.000 quench practically....youll be nearly smacking the head with the piston crown.

gt1 wont do much of anythingand youll still be held back over 5500rpm.

don't forget that the SII 3800 even with the longer L36/26 (NA) rods have a horrible rod/stroke ratio and the resulting geometry means poor cylinder filling at high rpm that can really only be fixed with with something "assisting" airflow.

with that cam and an oem dish/chamber limiting you to 9.6ishto1 compression ratio id say youll be at about 240 crank

**bachert24** · 06-07-2015

Chrsmi1 read post 3 on the second link you sent me. Thank you for proving me right. Also remember my car is a couple hundred pounds lighter and is rwd. People put your pride away and stay on topic, I'm not looking to see who has a bigger wee wee, I'm asking about rods and pistons. If you're looking to be right call zoomer and Vanessa over at zzp and tell them how you feel about it. Again, stay on topic!

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**chrsmi1** · 06-07-2015

Originally Posted by bachert24

Chrsmi1 read post 3 on the second link you sent me. Thank you for proving me right. People put your pride away and stay on topic, I'm not looking to see who has a bigger wee wee, I'm asking about rods and pistons. If you're looking to be right call zoomer and Vanessa over at zzp and tell them how you feel about it. Again, stay on topic!

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Well Good luck then bud. Start a member thread so we can keep up with the progress. Hope you hit your goal.

**Turbocharged400sbc** · 06-07-2015

you were talking about putting l67 pistons on NA rods so I naturally assumed that you hadent done any real in depth research.

without custom pistons your not gonna get ove 9.6/7 to 1
the old zzp car had a custom set of pistons and if I recal it was pretty well gutted

your still looking at making your 200hp/v6 into 240ish so its nothing to sneeze at but you wont get to 300 without dumping cubic dollars into it that you could top swap a stock NA shorty for 500$ and pull 260 crank readily

**bachert24** · 06-07-2015

Originally Posted by Turbocharged400sbc

you were talking about putting l67 pistons on NA rods so I naturally assumed that you hadent done any real in depth research.

without custom pistons your not gonna get ove 9.6/7 to 1
the old zzp car had a custom set of pistons and if I recal it was pretty well gutted

your still looking at making your 200hp/v6 into 240ish so its nothing to sneeze at but you wont get to 300 without dumping cubic dollars into it that you could top swap a stock NA shorty for 500$ and pull 260 crank readily

Only issue with that is I can't top swap on a camaro, too much customization dollars.

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**Turbocharged400sbc** · 06-07-2015

welding up a TB plenum elbow to fit would seem to be a far cheaper option than custom domed forged pistons

**REDCRAPGP** · 06-07-2015

Originally Posted by bachert24

Only issue with that is I can't top swap on a camaro, too much customization dollars.

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http://www.grandprixforums.net/threa...g-back-Teasers!

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**bachert24** · 06-07-2015

Originally Posted by Turbocharged400sbc

welding up a TB plenum elbow to fit would seem to be a far cheaper option than custom domed forged pistons

Think so? I suppose it's worth looking into. I think the holden 3800 has a rwd s/c version. I wonder if I could get my hands on one, and more importantly, how much customization for that?

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