I have a 406 with AFR eliminator 195's, solid "bracket race" (252/260@ .050, 106LSA)cam, vic. jr, and 750... If money allows, i would like to swap out the flat top pistons for some 20cc reversed dome pistons, and replace the solid cam w/ a hyd. roller, and replace the carb and vic intake with a tpi setup i have with 58mm TB, and manage it all via megasquirt, or commander or something.

one question i have is what would be one of the best cams for a TPI 406 w/ AFRs, with boost in mind?
I was thinking of one of the smaller XFI hyd. rollers, 113 LSA
or a very mild LT1 cam???
Im not against custom grinds, since i have to have it made for a small base circle anyways...

another question i had is for twins on a 406 intended for 60/40 street/strip use, wouldnt you want like a t04 or something not too awful large? because i have a brand-new in-the-box "ebayT70" (62mm) and could buy aqnother, but i am guessing it would be quite a bit on the large side...????

I just want to make 475-525 @ the wheels, with good street manners, run low/mid elevens @ 120ish, hopefully on pump gas, with mild converter and like 3.08s or 3.23s....

you know, just to hnag with the procharged LS1's and Kenne Bell'ed Cobras.......lol
(ps: its going in an 89 formula, TH350, 3.23s MT drag radials, etc.

 

Ditch the ebay turbo.

 

406+TPI+Twin Turbos= Putting the tires up in smoke no matter what you do.

Id say stay on track just as you plan but convert your Vic jr over to EFI and get a elbow to bolt up a TB to.

This will give you an all around bad ass setup. the 406 will already produce gobs of trq. the Vic jr will give you ton more RPM then the TPI (unless you use a miniram,HRS or converted Lt1 intake)


Run the snot out of the ebay turbo. They are only 160bucks There are reviews of people with good luck and bad luck with them. So your not gonna know untill you give it a shot.

 

Checkout the new carcraft......

 

After thinking about it, im not sure about the TPI choice either. Lord knows iv'e run the hell out of mine well past any sane limits! If the ultimate torque monster is your goal for a fun street car then use it. The 406 will be THUNDERING out low speed torque with it but with more cubes than my 350 it will definitely limit power potential down the road compared the a victor EFI conversion.
I guess its all in how you look at the combo. Obviously one can take you into the 9's so can a person really say it holds back the combo? It wont make as much total power as a victor but the torque and fun factor make up for it to a point and makes for low RPM reliability and a mellow gear ratio for the street too!
Them stupid intakes that shouldnt be right at all seem to have more going for them as a total package then they ought to! Its one of those weird combos that WORK for no apparent reason.

 

Marty, Im sure its in your thread, but i didnt notice... Are you running speed density instead of mass air??
and where did you buy your injectors and how much did they cost? all of the large ones(40lb/hr and bigger) seem to be biggg bucks..


Im not a huge fan of TPI for N/A but like you said for boost, its just one of those things that works and no one knows why..
i really like the thought of mild converter, and 3.08's......my ultimate goal would be to drive to the track (about 65miles from my house), run mid elevens or so, and drive it home. Torque is King.

I have Keith Black flat top 2 valve relief pistons in my 406 now, if i use a 20cc reverse dome piston for 4.155 bore w/ 5.7 rod, is this going to lower my CR enough to run moderate boost... hopefully it'd bring it down to the low 9:1's
or is there another dished piston out there that would suit me better?
P.s, my heads are 64 or 65cc chamber and the current pistons are in the hole about .020......
My motor has less than 20 break in miles on it, and was bored .030 over, i was gonna have the bore checked and just put a new set of forged dished pistons and new rings right in.


What Hyd. roller cam can i use for this many cubes, tpi, and boost?
my cams a small base circle though also
is 112LSA enough or do i want 114LSA?

 

Im speed density with the Holley Commander setup. Your small chamber heads will make it difficult to get the CR down where you want it. I wish you could get around 8.5 to 1 cuz if lots of street driving is the goal, 9 to 1 on pump gas and 200 deg. water temps definitely limit the boost. Meth injection and 9 to1 could work pretty darn good! Im only worrying about the CR because every 400 i ever owned seemed to be ping happy in N/A applications around 9.5 to 1.

 

thats what i was afraid of is the CR still not being low enough... like i said i have driven it extremely few mile but so far it hasnt pinged/knocked at all on 93octane pump gas, and i figure the CR now is 11.3-11.5:1, (about 34 degrees timing)

using the 400 that i have would save me the money of machine work and a crank(which is new) but i was going to replace the pistons/rods anyways,..... would i be better off using a 350 block for availability of 8.XX:1 pistons?
I really dont wanna get rid of such good flowing heads just to change CR. also i have a standard bore ealry 70's "010" 4 bolt main block, that i probably could afford to rebuild for boost.... what piston would be ideal w/ a 64cc head?

thanks for all the help so far.

 

well i dont know what i am going to do as far as the 350 vs. 400(prob 8.5:/8.8:1 in the 350 block), and i hhave for now changed my mind on twins... i like them better but i have the 62mm turbo that i would have to get rid of and try to find a pair of smaller ones..
so i am going to run the ebay turbo for now :-X, as a single...(w/ TPI)
the good news is i have started fabbing the single setup, and is going unexpectedly well. pieces are just "falling"into place and i think it will be one of the nicer single setups out there on a third gen.
i have to order a few miscelaneous U and J bends but i promise i will get some pics up for the critiqueing to begin...lol

who knows how long the ebay turbo will last, it probably wont make record breaking peak numbers, but oughta spool pretty damn good for a single.
i am mocking it up around the 305 thats currently in the car.. maybe i'll start it up with it on that motor just to make sure oiling is setup okay before putting it on a nice motor. who knows, maybe it'll best my 12.60 that the car ran with a 150 shot.....

...pics by next weekend

 

Thats gonna be a cool setup! Im not sure what the best plan is between the 350 or 400 since the 400's cubes and stroke are bitchin for a turbo but the blocks seem to be weaker and possible head gasket issues too with the 400. I dunno.

 

JE has some 36 cc reverse domes, which will get you close to 8.5:1 with a 64cc chamber. TPI with good runners and a good base is not bad for a boosted motor, the big downfall of them is the tiny port size, but aftermarket bases and runners are out there for them.

 

Any idea who sells them? or are they from JE directly?

i've looked in doug herbert, jegs, summit, etc. no luck




I've got most of my hot side plumbing cut, routed and tacked for now...
what size should my cold side be on a setup like mine?
62mm turbo, 10-18lbs of boost depending on fuel run. and intercooled....

 

http://www.jepistons.com/cat/je/auto/chevy_sb/extreme_duty_23_inv.shtml
Anyone who sells JE can get them. Summit lists part #131633 for $738.88 for a set, that's a 4.155" bore 36cc reverse dome for 5.7" rods. Jegs lists them for $719.99. You can try calling JE directly, but I don't think they will under sell their dealers.

 

thank you very much for the information.

that would help me out a ton if i could use the 400 for boost, since all the machining and crank is new/fresh.



those pistons are pricey though huh? guess ya gotta pay if ya wanna play.


anyone got an idea of what size the cold side should be? and where to get aluminum bends and silicone connectors at a decent price??

 

Speakin' of KB pistons, you could just use what I'm gonna' use for my cruiser truck motor and get a set of part number KB126, about $250 and feature a big -30cc dish. From your other components I was just figuring that you were going for a somewhat budget-minded approach (except for those badass AFR heads, the Eliminators look impressive!) They're listed right in Summit, on the large KB pistons page. Good luck, you're gonna' be seriously HOOKED!

---==Temio Williams
Yuba City, CA

 

Stay clear of hypereutectic pistons in a boosted engine. They are ok in a mild engine, but you have the potential to make some serious power, and it will get a lot of strip time. It's cheaper to do it right the first time than to do it twice.

I've seen hypers last in 500+ HP engines, but I've also seen more than my share of failures, not worth the risk.

 

GrapeApe makes a good point, the hypereutectic pistons are VERY sensitive to any hint of detonation. They don't "go plastic", like a forged unit, they essentially "shatter" . I've found the best prices on JE and SRP pistons on the CNC Motorsports Ebay store, better than Summit/Jeg's. Good luck bro'!


---==Temio Williams
Yuba City, CA

 

thank you very much for the info/advice, still doing some more research and of course progressing as money allows..
thanks guys,
Keith