[92lx5oh]

I am building an engine combo and want to know what you guys think about it. like combonation potential, estimated hp/tq numbers

Here goes:

306ci using A4 block
Scat 4340 Forged steel crank and rods
TRW L2249F pistons (12.0.1 compression ratio)
Lunati cam (242/252 duration @50) (600/620 Lift) (110 LSA)
AFR 185 Heads
Trickflow R Intake
75mm TB
76mm MAF
30lb Injectors
1 5/8 Longtubes

theres more but these are the basics

Thanx

[88BlueGT]

Im not good at the guessing game but maybe like 330-350 rwhp. Just one question, is that all that you are doing to it? Keeping it NA? If so, why the A4 block?

[TurboLX]

about 320-350

[1slo5.0]

Should be no problem making 340hp or so at the wheels.

[mikebert]

What kinda crazy head and piston combo is that to make 12:1 and have a cam with 600/620 lift?

I can't find those pistons online, so I don't know their specs, but do they have a dish in them the size of a grapefruit?

[1slo5.0]

Originally Posted by mikebert What kinda crazy head and piston combo is that to make 12:1 and have a cam with 600/620 lift? I can't find those pistons online, so I don't know their specs, but do they have a dish in them the size of a grapefruit?

I don't have the piston information in front of me but it takes about an 8cc dome to achieve 12:1 with the 58cc AFR 185 heads that he is using. I know TRW makes a dome piston for a 302 and I'm sure that is what he has.

[mikebert]

Originally Posted by Darrell Originally Posted by mikebert What kinda crazy head and piston combo is that to make 12:1 and have a cam with 600/620 lift? I can't find those pistons online, so I don't know their specs, but do they have a dish in them the size of a grapefruit? I don't have the piston information in front of me but it takes about an 8cc dome to achieve 12:1 with the 58cc AFR 185 heads that he is using. I know TRW makes a dome piston for a 302 and I'm sure that is what he has.

And that's enough to keep his valves from tap dancing across the piston?

[92lx5oh]

Sorry I made typo.

The Pistons are TRW L2249N, Not the NF ones. The L2249NF have a 4cc dome and have a 10.5.1 ratio with a 58cc head and the 77 & later 8.206 302ci deck height. The L2249N have a 7.8cc dome and have a 12.1.1 ratio with a 58.2cc head. They dont make the L2249N piston anymore.

The cam is the Lunati 51018 hydro roller cam. Its got 560/576 lift but with my 1.72 rockers it would have 600/616 lift

I also have an NX plate kit that I might throw on it. I want to see how it does N/A first.

Also, one of my freind said that anything over 24lb injectors and a really big cam is going to need a custom tune or it wont run good. Do I need a tune ?

[ih8chevy]

i havent seen the pistons but they gotta be something else to have that big of cam and afr 185 heads all fit. and if u get that working i would def say upwards of 360 wheel. but i dont c how ur gonna get he pistons to not smack the valves with that cam and those heads. but all the same good luck

[mikebert]

You're got a heavily modded car for the street, so a tune won't hurt. You won't need a tune necessarily just to run well. The MAF will take care of the injector sizes, so you don't have to worry about that. 24 is only a notch up from stock, so that's not too serious a change, but yay for computers because it's all taken care of with MAF calibration.

But if you still have more plans, hold off on the tune until you get everything done.

Edit: I misread about your injectors, but even with 30lb it doesn't matter. Just make sure you have the right calibration for the MAF, get good fuel pressure and that's your fuel system worries taken care of.

[1slo5.0]

Originally Posted by 92lx5oh Sorry I made typo. The Pistons are TRW L2249N, Not the NF ones. The L2249NF have a 4cc dome and have a 10.5.1 ratio with a 58cc head and the 77 & later 8.206 302ci deck height. The L2249N have a 7.8cc dome and have a 12.1.1 ratio with a 58.2cc head. They dont make the L2249N piston anymore. The cam is the Lunati 51018 hydro roller cam. Its got 560/576 lift but with my 1.72 rockers it would have 600/616 lift I also have an NX plate kit that I might throw on it. I want to see how it does N/A first. Also, one of my freind said that anything over 24lb injectors and a really big cam is going to need a custom tune or it wont run good. Do I need a tune ?

It will run fine without a tune. However if you have a reputable tuner work some magic on it you will surely find some more horsepower. I've run 36lb injectors on a naturally aspirated street motor with no problems at all.

[1slo5.0]

Originally Posted by ih8chevy i havent seen the pistons but they gotta be something else to have that big of cam and afr 185 heads all fit. and if u get that working i would def say upwards of 360 wheel. but i dont c how ur gonna get he pistons to not smack the valves with that cam and those heads. but all the same good luck

Why would the pistons smack the valves? I have off the shelf Probe pistons and a cam with over .700 lift and my valves don't come anywhere near my pistons. I've run .620 lift with stock pistons already. All aftermarket pistons have valve reliefs and most aftermarket pistons have larger and deeper valve reliefs than stock pistons. Valve timing has more to do with piston to valve clearance than anything.

[92lx5oh]

I didn't put the heads on yet so thats a plus for PTV clearance.

Do you think the valves will hit. The pistons do have pretty deep valve relifs.

[1slo5.0]

Originally Posted by 92lx5oh I didn't put the heads on yet so thats a plus for PTV clearance. Do you think the valves will hit. The pistons do have pretty deep valve relifs.

You should always check valve to piston clearance. It probably won't be an issue but it only takes a little bit of time to check.

[Stangzilla]

Can he run pump gas with 12:1 comp?

[Darrellx14]

I've always heard no more than 11:1 on 93 octane, and even with that you're gonna have some pinging going on more than likely. But a higher octane mixed with 93 would probably be the best bet.

[Stangzilla]

Originally Posted by Darrellx14 I've always heard no more than 11:1 on 93 octane, and even with that you're gonna have some pinging going on more than likely. But a higher octane mixed with 93 would probably be the best bet.

Thats what I thought too no higher than 11.5:1 with a good tune. If it is a street car I personally dont think thats a good move on the compression side..

[mikebert]

Originally Posted by Darrellx14 I've always heard no more than 11:1 on 93 octane, and even with that you're gonna have some pinging going on more than likely. But a higher octane mixed with 93 would probably be the best bet.

Even with aluminum heads?

[Stangzilla]

Thats what I thought.. But I could be wrong.. Been know to be..

[1slo5.0]

Originally Posted by Stangzilla Can he run pump gas with 12:1 comp?

Absolutely not. He could if he ran about 22 degrees of total timing but the car would be a slug with the timing retarded that far and would probably run hot. I wouldn't run any more than 10:1 on pump gas. We just had a similar conversation to this on another site and reputable tuner/NMRA racer said he tried running 11:1 with an aluminum headed 306 on pump gas and the engine didn't like it at all. Just by switching to 100 octane fuel it picked up a ton of power.