another 4.1 budget build

[big steves gn]

Hey guys doing a 4.1 budget build need help deciding on cam and turbo Any input would be appreciated
the car has 3 in down pipe
60 pound injectors I think I'm going to order some new 80 lb
afr
front mount intercooler
3200 lock up trans
My goal is to run a Hi 10- low 11 second pass
I was thinking about going with that 218 218 cam and a 6766 turbo and run only about 20 pounds of boost I'm a little scared of getting any knock if anybody knows any good 4.1 combinations let me know

 

[earlbrown]

What's your static compression?

 

[big steves gn]

What's your static compression?

I'm not sure I went with the sealed power Hypers 30 over pistons with Molly rings I was told I should be around 8 to 1

 

[TexasT]

Id be scared of any knock if I used those pistons , too.
Do you plan a lot of street driving?
Why so little boost?
218 is nice but for a track car I might be inclined to step to a 224/224. Especially if you plan on some ported heads.
With traction, you shouldn't have trouble getting to the 10s but it will probably need more boost.

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[regalracer1987]

i ran a 4.1 with the hyper pistons, home ported 8445 heads, 72# injectors, 215/220 roller cam from full throttle , turbo tweak chip ,6776 cast wheel ball bearing turbo,3in thdp precision front mount, perfect street and strip car i made 560 hp at the wheels on the mustang dyno with 21# of boost and ran 6.51 in the 1/8 109mph it was a good engine to that point but the sealed power Hypers are only good to about 600 rwhp. with no knock mine gave way when i turned it up 28# of boost i broke 5 of the pistons right at the wrist pins. i am building another one reusing most of the parts just gonna spend the cash on forged pistons from full throttle

 

[earlbrown]

I'm not sure I went with the sealed power Hypers 30 over pistons with Molly rings I was told I should be around 8 to 1

Every time I've every read ''I was told'' when it comes to static compression, that person was wrong. Measure what you've got and go from there.


I have sealed power hyper (for now).030"'s in my 4.1 and I had to go through all kinds of heroics to get 8.99:1 static.

You're going to overcam this engine if you're not carefull and throw away all kinds of power, efficiency, throttle response and spool.

 

[Nick Micale]

My experience with 4.1 street builds have lots of mid-range torque as well as great street manners with a 212/212 roller cam.

As far as a turbo, with your 67 and decent head work, low 10's will be easy.

You will need the 80# injectors and a converter with a lot more stall than 3200, or you will never have traction on the street with all the torque available!

 

[big steves gn]

What would you guys recommend for a flat tappet cam
and how low did your pistons fit in the cylinder I haven't measured mine but they do seem a little low I might have to take this motor back apart and have the block decked a bit

 

[Heskahoka]

Nick built me a 4.1 with a 212/212 flat tappet cam and I am very happy with it. I am using the ZDDPlus oil additive to keep it healthy.
Very docile on the street with a good idle, but will burn the tires at will.
I am also going with the 6766 turbo very soon.

 

[earlbrown]

What would you guys recommend for a flat tappet cam
and how low did your pistons fit in the cylinder I haven't measured mine but they do seem a little low I might have to take this motor back apart and have the block decked a bit

00I'd say they're way down in the hole... I'm guessing around .078" ~ .080" or so... add the head gasket to that and you're quench distance is none existent (and you're static compression sucks).

Back when I built by shortblock I had to take it all the way back down, remove the cam bearings and deck it .035". That made it .010" shorter than a 109 block. Coupled with some .027" Cometics, that gave me right at 8.99:1 static and it clears my too big 215/220.


Looking back I wish I would have stopped and did my custom/shelf pistons but I'd been without my car for 6 years and I was tired of waiting. My next 4.1 won't have that problem. I'll have forged pistons and a the ability to use normal VR gaskets instead of having to run Cometics.

 

[big steves gn]

Okay I'm going to go with the 212/212 flat tappet cam going to take this motor back apart and have it decked im going for a 9 to 1 compression ratio or just under I'll let you guys know how it goes
thanks for all the help

 

[TexasT]

Don't take off too much the deck.isn't that thick to begin with.

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[Undercover87T]

My 4.1 was a budget build. Stock crank/rods, .030 TRW hypers, 212/212 roller, ported irons, 6262E, and a 3200 stall. Rest of that combo in my sig. Super fun street motor, quick spooling. On 19-20psi, 19degrees timing, and pump gas only I went 11.95@115 with a soft launch. Turn it up to the mid 20's with alky or race gas and your in the mid-high 10's no problem. Currently rebuilding it as a 4.5 with all forged parts.