Compression & Power Adders

Old Skooler · May 10, 2012

Im trying to plan and budget my next big performance upgrades. Currently I have a 331 with 11.1 comp. I'm swapping out my edlebrock heads for AFR 205, it's currently a carb motor with a 750 HP and victor jr high rise intake. I'm told the cam is a comp can 610 lift (I didn't install it).

I'd like to go either spray or turbo but I'm not sure about the 11.1. Can a carb motor have turbo and will my compression limit the boost? Any help or advise is greatly appreciated.

srtthis · May 10, 2012

you CAN turbo it... the boost you can run will depend on the fuel and timing you run. id also ditch the carb since you'll have to go blow threw that way and you'll be opening up another can of worms with that one. id also get a cam set up for a turbo

Noobz347 · May 10, 2012

Old Skooler said:
Im trying to plan and budget my next big performance upgrades. Currently I have a 331 with 11.1 comp. I'm swapping out my edlebrock heads for AFR 205, it's currently a carb motor with a 750 HP and victor jr high rise intake. I'm told the cam is a comp can 610 lift (I didn't install it).

I'd like to go either spray or turbo but I'm not sure about the 11.1. Can a carb motor have turbo and will my compression limit the boost? Any help or advise is greatly appreciated.

In what block?

Old Skooler · May 10, 2012

@ noobz it's a Mexican high nickel (confirmed) forged eagle rotator and forged probe pistons

@ srtthis so do you mean go EFI? I know nothing about turbo I'm starting my research now so if this is a stupid question bare with me.

Noobz347 · May 10, 2012

Brother... If you're already pushing 700+ HP out of that block then you should count yourself lucky that it's all still in one piece.

CarMichael Angelo · May 10, 2012

OLD Skool, I want to know how you are making 750 HP N/A on a 331, w/ a smaller head than a AFR 205? Every other combination I see like that is 300-350 Less HP?

The pros building engines for the engine masters challenge managed to get 675 HP out of a 344.
But that was with 16.49:1 CR, and a mechanical roller that has .750 lift, and 260 degrees duration. SVO heads w/ a 2.130 intake valve
(probably slightly larger than an AFR 205 I'd think,....but that's just me )

I think you might wanna re-evaluate your HP numbers.

srtthis · May 10, 2012

yea as they said your HP are fishy.... the motor in the race car at 440" yates headed 14:1 only made a little bit over 930hp

but HP aside... 11:1 compression isnt unheard of to run a turbo on. is it common HELL NO! but it can be done. so taking out doing a blow threw set up with a carb in a boosted application EFI is the way to go on something uncommon like a high compression turbo motor

Old Skooler · May 10, 2012

Sorry auto correct got me its suppose to read 750 Holley not HP, fat fingers and an iPhone. My car was just Dyno 375 rwhp if I was at 700+ I'd be done. @ mad mike your calcs are correct.

I'm looking to get around 500rwhp. Even though my edelbrocks are ported I know they're not the best that's why I'm working on the AFR's. Nitrous is probably the easiest route to go but I've been seeing turbo set ups and the numbers are huge.

srtthis · May 10, 2012

if you have high compression and a carb nitrous is the route id go personaly. you can pick up a plate kit for a 4150 pretty cheap.

CarMichael Angelo · May 10, 2012

Ohhh 750 DP, NOT 750 HP. That's much better.

Yeah^^ I agree. Cheapest bang for the buck. You are already w/i an easy hit to get the number you seek HP wise. Your engine wont even know it's being leaned on. If you wanna make 500 HP, tag the button. When you want to keep on getting the gas mileage you currently are getting just forget that it's there.
Or you could get just stupid, and put a fogger on it, wow the crowd at the pop stands when you open the hood, and put a double vent blue LED illuminated purge system on it, and just dump the bottle out at your local Sonic when the waitress's walk by w/ trays of food.

NIKwoaC · May 10, 2012

Haha, you guys thought he meant 750 horsepowerz... LOL...

NIKwoaC · May 10, 2012

Hey, if you're switching heads, why not run less compression? 9-9.5:1 would be much easier to pull off on boost.

Nitrous is another story. Nitrous and compression get along.

90lxcoupe · May 10, 2012

If you run a blow thru the carb will help keep the intake temps lower, which will help keep detonation at bay. If i were in your position i would probably just spray it unless you can get e85. With the inconsistencies of pump gas i wouldnt risk running boost on 93 octane. If you can get e85 locally, then that is the way to go.

Even on motor at 11:1 you have to be very careful with the tune up on pump gas. I had a local pump 93 octance in the tank and went to a car club dyno day, one of those 5 pulls for 50 buck deals. I ended up pulling 9 degrees of timing out of it before it stopped detonating. I started with 32 degrees, and ended the session with 24 degrees. The car made 390 hp that day. Something was way off, so i rented a dyno, put a full tank of sunoco 93(i verified with the station that they only use sunoco fuel), and put the timing back up to 32 degrees for the first pull. It made 419rwhp. I took the timing back down to 27 or 28 degrees and the car made 430 rwhp. 28 degrees was where it stopped detonating that day, and he car was really happy there.

So the point to that story is pump fuel is nothing to get complacent with, there was 40 hp just in changing to a different 93 octane. More importantly the car dosent detonate anymore. If my car was boosted, or sprayed on that first dyno day, the motor would have gotten hurt, no question

srtthis · May 10, 2012

PUMP E85 is the same way as Pump 93... ive heard reports as low as E6x

90lxcoupe · May 10, 2012

The inconsistencies can be the same yes, but the added octane of e85 is where it the advantage comes in. If you get a batch of e85 that is say e70, and tune the car on that you will have a very safe tune up. e85 is super easy to test the ethanol conent, so there is no excuse for not knowing whats in the tank. The best 93 octane will never be equal to e85. Ever.

Also, you said plenty of guys run 11:1 with boost, thats true, but not a whole lot of windor guys do it. It takes a very efficient chamber design to pull that off. Which is why the new 5.0's make it look easy

Gearbanger 101 · May 10, 2012

srtthis said:
if you have high compression and a carb nitrous is the route id go personaly. you can pick up a plate kit for a 4150 pretty cheap.

This.

srtthis · May 10, 2012

90lxcoupe said:
The inconsistencies can be the same yes, but the added octane of e85 is where it the advantage comes in. If you get a batch of e85 that is say e70, and tune the car on that you will have a very safe tune up. e85 is super easy to test the ethanol conent, so there is no excuse for not knowing whats in the tank. The best 93 octane will never be equal to e85. Ever.

Also, you said plenty of guys run 11:1 with boost, thats true, but not a whole lot of windor guys do it. It takes a very efficient chamber design to pull that off. Which is why the new 5.0's make it look easy

most of the guys i know doing it are windsor guys
and your right it is very easy to test the E85 fuel... but its one of those things. everyone thinks all E85 is the same and its far from it.

NIKwoaC · May 10, 2012

90lxcoupe said:
The inconsistencies can be the same yes, but the added octane of e85 is where it the advantage comes in. If you get a batch of e85 that is say e70, and tune the car on that you will have a very safe tune up. e85 is super easy to test the ethanol conent, so there is no excuse for not knowing whats in the tank. The best 93 octane will never be equal to e85. Ever.

Also, you said plenty of guys run 11:1 with boost, thats true, but not a whole lot of windor guys do it. It takes a very efficient chamber design to pull that off. Which is why the new 5.0's make it look easy

The new 5.0 also has oil-spraying piston cooling jets, knock sensors, and octane sensing logic programmed into its ECM, so it's got a few things going for it on that front, haha.

BadBlue68 · May 11, 2012

Old Skooler, how has your 331 performed? I am in the beginning stages of my own build and I am planning to stroke my 302 to 331/347. All of the kits I am looking at seem to put my CR in the 10-11 range with the heads I have (AFR 165s with 58cc chamber). I had previously thought 11:1 was too high for pump gas, but I see that's right where your is!

Gearbanger 101 · May 11, 2012

BadBlue68 said:
Old Skooler, how has your 331 performed? I am in the beginning stages of my own build and I am planning to stroke my 302 to 331/347. All of the kits I am looking at seem to put my CR in the 10-11 range with the heads I have (AFR 165s with 58cc chamber). I had previously thought 11:1 was too high for pump gas, but I see that's right where your is!

Dished pistons are available for all kits if you don't want the high of a compression ratio.

Compression & Power Adders

Old Skooler

srtthis

the guy doing it does every local racers rear end

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

Old Skooler

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

CarMichael Angelo

my rearend will smell so minty fresh,

srtthis

the guy doing it does every local racers rear end

Old Skooler

srtthis

the guy doing it does every local racers rear end

CarMichael Angelo

my rearend will smell so minty fresh,

NIKwoaC

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srtthis

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