This is my first post on this forum; great job on the forum guys tons of information. I am in the beginning stages of a supercharged injected slant six for drag racing only. I would like to go close to 3.50 on bore and make as much HP as possible with the dollars that I have. I am hoping for 375hp in a 1800 LB. car. 1800 pounds is not easy we'll see how close I get. I have a M-112 Eaton supercharger , I am going to Megasquirt the port injection and spray water/alcohol under the blower to cool the air charge. I will have many questions as the project move on, however I have one to start off with in this post. Has anyone tried the Speedpro L2206F forged Corvair piston?? standard bore is 3.4375 and they are available .030, .040 and .060, the compression ht. is 1.58-1.60 range, the pins are smaller around .800 but I am going to use a custom rod anyway.

$71 from Summit is the cheapest I found that piston. That's $426 a set which is more than the $466 custom Weisco pistons as the $466 pistons come with rings.

Also, it's easier to inject water/alcohol into the blower inlet as the inlet isn't under boost and it will help seal the rotors to the case and increase boost slightly.

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Joshua

Josh thanks for the reply;
The pistons can be had for $299.99, you could bush stock rods and use pin buttons which are available, as there is no provision for keepers.

I would like to spray the alcohol over the blower, however the Eaton blowers have a Teflon coating and they say any hydrocarbon fluid will eat away at the coating, This would end up as small particles going through the engine.

I may go with one of the custom piston deals I have seen here. I just wanted to know if anyone had tried the L2206F's I think they would work for a med-high performance setup.



Jim

I use the 2206 Corvair piston in my race car. When I bought the pieces for that engine back in 1974 they seemed like the best solution to use the the 198 rods. Back then TRW pistons were all the rage for race motors or all kinds. I liked the 1/16" wide rings particularly and went with the stock 3.4375 bore size to keep my cylinder walls as thick as possible. I had a shop out in New Jersey enlage the pin bores to slant 6 size. I shortend the pins to 2 1/2" and pressed them into the rods. You will have to cut valve notches to use any kind of a serious cam so I don't think they would be any cheaper than the Weisco pistons that are frequently mentioned on this site.

You can adjust the compression to what ever you want by milling the head and/or the deck. Another problem with the Corvair piston is the lack of a .005 oversized ring for file fitting the gaps. I use some 3 7/16+ .010 rings that you can get through Harley Davidson dealers. Bottom line is the Corvair pistons work just fine but require quite a bit of custom work. You are better off to go with an aftermarket forging like the Weisco and get it made just like you want it. The K-1 H beam rod that they also offer is far superior to 198 rods at a very reasonable price.

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If you didn't drive it there, it's not a street car.

Welcome to the board!

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Official Cookie and Mater Tormentor.

Thanks Zilla;
and Exner Geek excellent info, so you've been racing slant six's since 1974? Wow! Sounds like I'm in the right age bracket here, I've been racing Chevy v8's boocu years, 17 years in circle track mostly dirt and drag racing for past 7 years. I build custom tube frame cars and I did a BB Duster for my friend and we go to Vegas every spring for the Mopar Nats. I just thought hey why not build something to race there myself since they no like my Camaro.

Jim

Make sure to stop by and see the Slant guys at Vegas. You'll meet the nicest bunch of people you ever did see.

You may also see some of the weirdest things you ever did see.

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Official Cookie and Mater Tormentor.

Do the Slant guys still fly tipis in the pits in Vegas?

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Yeah....Im the one who destroyed this rare, vintage automobile.....

What happens in Vegas...........................

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Official Cookie and Mater Tormentor.

We have been waiting for Sandy to return to LV before flying any more tipis... no one does it the way he does, he's a 'professional'!

I have also run the Covair pistons and they work well.
I had to open-up my rod pin bore (small end) to .927 so starting with a good set of rods with centered pin bores was important.

I also agree that valve notches are needed if the cam numbers get big.

We are planning to be in Vegas this your so please stop by... or better yet, plan to have dinner with the group on Friday or Saturday night.
DD

DD;
Thanks for the invite, my group from TopGun usually circles the wagons pretty good at Vegas also. Tipis??

I am leaning toward custom or weisco pistons not sure if the Corvairs will stand up to 375 HP (hoping) and 12-14 psi boost? I just noticed that they are in our bore, CH, forged criteria and had not seen them discussed. Either way I've got some time to decide on pistons and rods. Custom blower manifold and injector rails will keep me busy for a bit.

I have 1.70/1.44 SS valves and do my own head work, do you think larger on the exhuast side would be helpful with the supercharger?

Hope to see you guys in March I have to rebuild Larry Cravy's 500 CI Wedge before then.

Jim

Sounds like the SL6 group... we tend to have a good time in Vegas!

As for Tee Pees... you had to bee there in 2006 to get the joke...
Here is a shot of our pit area when BC Sandy paid us a visit that year.
DD

Keep me updated with your supercharger project. I'm going with a m62 onto a 170. I plan on having a 5lb pulley for street and a 10lb pulley for strip. I will tune for both and simply load the other fuel map. The megasquirt program is a little difficult to learn, but through perseverance you'll get there. May I suggest a custom gas tank over adapting the stock one, I've had nothing but problems with dealing with the stock one (I'm a college student though).
Custom cam and strong pistons are a must! The corvair would be cool, the 2.2L hypers are cool, but honestly do you want to risk failure for $100? Valves aren't high on my list for a supercharged engine. However, for the money you can't beat engrbldrs valves. So I 'm thinking stock intake and oversize exhuast.

The slant head flows better % wise on the exhaust side than the intake. The fast NA guys run more intake duration for this reason. For a blower engine I'd run a single pattern cam.

Joshua

Thanks Guys for all the input made me feel real welcome here.

runvs_826, will do on the project updates.

And Joshua do you run a supercharger?

Jim