Guys,

Im finally getting around to rebuild my motor and this time, i want to procharge it.

Ive got a 67 Camaro with a 468 BBC and GM 990 iron heads. I have a TKO 5 speed and a 9" rear with 35 spline detroit locker. Tires are 275/40/R17 with Mickey 275 drag radials. I am planning on installing under the car weld in subframe connectors.

What is the max hp/tq i can put to this car and have it be enjoyable to drive? I want at least 600 rwhp/tq, but would prefer more...

What can my car handle powerwise with a centrifugal blower whose power outptut comes with RPMs.

What would you guys recommend for the procharger, heads, cam and compression ratio? This will be non intercooled for now, but i am open to ceramic coated pistons, and water injection.

thanks guys

jeff

Guys,

Im finally getting around to rebuild my motor and this time, i want to procharge it.

Ive got a 67 Camaro with a 468 BBC and GM 990 iron heads. I have a TKO 5 speed and a 9" rear with 35 spline detroit locker. Tires are 275/40/R17 with Mickey 275 drag radials. I am planning on installing under the car weld in subframe connectors.

What is the max hp/tq i can put to this car and have it be enjoyable to drive? I want at least 600 rwhp/tq, but would prefer more...

What can my car handle powerwise with a centrifugal blower whose power outptut comes with RPMs.

What would you guys recommend for the procharger, heads, cam and compression ratio? This will be non intercooled for now, but i am open to ceramic coated pistons, and water injection.

thanks guys

jeff


Jeff,

my first Procharged 468 made about 800 rwhp so what you want to do is not a problem. I did have better heads, but otherwise a fairly simple combo.

With 91 octane I always have the pistons ceramic barrier coated. I also was not using an intercooler so I had water injection.

I had a D1SC at the time, but the new F series blowers are better. Cam was a solid roller with about .650 lift and 242/254 @ .050 on a 114 lsa. Fairly mild in a 468 but made excellent power. I was running a max of 14 psi at the time and about 28-30 degrees of full timing, but it was an aluminum engine with efi, so that allowed more than a cast iron block/head combo would.

I ran as much as 9.7:1 compression, but again aluminum engine. I would recommend about 9:1 to 9.4:1 on a street deal to maintain good off-boost manners and help mileage at cruise some.

Jody

Hey Jody,

The more i look into this, the more confused i get...

So whats the difference btween the D1SC and the F series in terms of the way they output power?

Does the F series have more "lag" being that its bigger? Would it be a noticable difference on the street?

Will the F series put out more power at a given boost level?

Whats the most power i can get to the ground without breakin parts or making smoke shows? again, ive got 275 drag radials on 17"s and a wide ratio TKO, detroit locker, 35 spline, cal tracs.... Ill do subframe connectors, but no tubbing..

In terms of streetability (lag, 91 octane, no intercooler, max power that actually makes the car go faster and straight) would the D1SC or F seies be a better choice?

Will my 990 heads get the job done, or should i pony up for some AFRs?

In theory, what would be the best bang for the buck: stock heads, cam, bigger blower, intercooler or nice AL heads, solid roller cam, smaller blower, no intercooler?

Thanks for helping me understand!

jeff

Hey Jody,

The more i look into this, the more confused i get...

So whats the difference btween the D1SC and the F series in terms of the way they output power?

Does the F series have more "lag" being that its bigger? Would it be a noticable difference on the street?

Will the F series put out more power at a given boost level?

Whats the most power i can get to the ground without breakin parts or making smoke shows? again, ive got 275 drag radials on 17"s and a wide ratio TKO, detroit locker, 35 spline, cal tracs.... Ill do subframe connectors, but no tubbing..

In terms of streetability (lag, 91 octane, no intercooler, max power that actually makes the car go faster and straight) would the D1SC or F seies be a better choice?

Will my 990 heads get the job done, or should i pony up for some AFRs?

In theory, what would be the best bang for the buck: stock heads, cam, bigger blower, intercooler or nice AL heads, solid roller cam, smaller blower, no intercooler?

Thanks for helping me understand!

jeff


An F1 is just a sped up D1SC. An F2 will move a lot more air, but for your HP goal any of those will exceed your power goal.

As far as power to the ground, mine was almost identical to yours, same diff, same trans, same tires, same Cal Tracs....... it would spin the tires at any speed in the first three gears, but that was at 800+ rwhp. If you back the boost down to 650-675 rwhp it'd be a much better street deal.

Better heads will yield big gains, especially on the exhaust side, but you can likely make your 600 rwhp with those heads, but you'll be near the end of their power. The exhaust is the biggest issue with them on a blown motor, and some AFR's or Canfields will likely add 75-100 rwhp at high boost levels.

You can make your goals without intercooling, but obviously the intercooler would be nice. Necessary, no..... but a nice idea. Without it figure on water/alcohol injection to be able to run a fair amount of boost on pump gas.

Whats the max boost for 91 octane? ceremic coated pistons, non intercooled, iron heads and block? about 8?

What kind of hp/tq differences would i see with the AFRs or Canfields at that max boost?

thanks

Whats the max boost for 91 octane? ceremic coated pistons, non intercooled, iron heads and block? about 8?

What kind of hp/tq differences would i see with the AFRs or Canfields at that max boost?

thanks


I ran 14 psi on mine without intercooling, but that'd drop to 10-12 psi on an iron motor, while still being able to run some timing. I mean on a street deal if you have to pull all the timing out to run a couple more pounds of boost it's usually not worth it. It's better to build the combo to run less boost and proper timing.

The better heads would make the same amount of power at less boost, so at equal boost there should be a noticeable gain. From what my buddy says on the big blocks he dynos the stock heads run out of breath by 600 rwhp, sometimes less, where with the aftermarket ones you could be 100-150 rwhp higher, maybe more.

By swapping heads to a better flowing head the boost level will drop, yet the power will go up in most cases. Once you re-pulley to get the boost back up then the power starts taking good jumps.

You could always try it as it is and upgrade heads later as the budget allows. Most people are thrilled with 600 rwhp, that's a lot of power. But then you have the few like me that always need more.

Jody

Jeff,
I agree 100% with everything Jody said, (he is on the money!)

Is your combo going to be EFI or carb?

With a good set of heads, about 9 to 1 cr, a cam around 245/255 & 650 like Jody used, an F1 at about 10 lb boost. I think your 468 will make over 700 RWHP.

It will be very streetable, just make sure it's aimed in a straight line when you press down on that right pedal.

A F-2 will go over 1500 in a race setup. With a BB chrysler 470 cid on alcohol F-2 19 psi 30 deg timing made 1520 hp @ 7200

A F-2 will go over 1500 in a race setup. With a BB chrysler 470 cid on alcohol F-2 19 psi 30 deg timing made 1520 hp @ 7200

WOW!

A F-2 will go over 1500 in a race setup. With a BB chrysler 470 cid on alcohol F-2 19 psi 30 deg timing made 1520 hp @ 7200

Just a bit above his power goal. ;)

Jody

sc68z28,

i saw your car in the magazine... youre at what 712 rwhp? hows your suspension set up? does your car shoot in a straight line?

very nice ride by the way... i drooled over it for a week

thanks

712 rwhp? hows your suspension set up? does your car shoot in a straight line?

very nice ride by the way... i drooled over it for a week



Thanks Jeff,
712 rwhp was with 14.5 lbs boost, small headers, 2.5" exhaust, and power steering.
It should be over 750 rwhp now, with 17 lbs, 1 3/4 headers / 3", and manual steer.

I am still working with muti leafs, Slide-A-Links, and QA1 adjustables.
Bolt in CE subframe connectors are attached to the 10 point cage.

With MT slicks it goes straight as an arrow, even spinning hard when I was trying 15 lbs of air in the slicks.

My first trip to the track a couple years ago, I tried a set of BFG drag radials. That was scary, I had to lift several times as it wanted to swap ends.

Good luck with yours, have fun and be safe. Bill.

Bill,

Do you have any boost vs RPM data that you could share?

thanks

Yes, Jeff, But be aware boost is the presure the motor is not able to swallow.
Big cubic in, big heads, big cam, will take more of that air the blower is making. It will also make big power.
When I first got my combo to together and only saw about 11#'s of peak boost, with the pully they said should make 15#'s, I was actually happy! This told me it was beathing better than expected and would make more power.

Here's RPM = boost and intercooled intake temps from my last data log, on a 80 degree day.With 1.91 over driven belt ratio, 5.0 to 1 internal ratio, F1 Procharger. 1500 foot elevation.

@ 4100 = 8 psi, 108*
@ 4500 = 9 psi, 111*
@ 5000 =11 psi, 114*
@ 5500 =12.5#, 117*
@ 6000 =15 psi, 121*
@ 6300 =16 psi, 126*
@ 6600 =17 psi, 131*

This was a 2nd gear pull, intake temps where less in 1st gear and higher in other gears, heat soak becomes a factor.

Also I found a chart that shows degrees of heat increase NON intercooled per pound of boost.

8 psi 99* increase
10psi 119*
12psi 139*
14psi 157*
15psi 166* increased air temp from friction when compressing air, thats plus ambient air temp! Seems like a lot of heat.

hope this helps. --Bill.

wow, the non intercooled increases are crazy...

so lemme ask you, these boost numbers... they are measured from a map sensor, right? (not calculated)

So with a bigger motor, cam etc youll have to spin a blower faster to make the same "boost"... cram more air into the motor... its not just spinning the blower faster that make the air temp rise, its the building pressure, right?

Its a certain boost level that determines how much timing, compression ratio etc that one can run, right?... timing/CR limits are not linked to the actual flow numbers... just a certain boost/pressure (short of detonation)

So with better flow, one could run more timing and more CR or bump up the flow to the point of the max allowable boost? (im guessing the boost option is a better return).

so better flow heads for example win in 2 ways: 1)for a given "boost" on a stocker head, they flow way more than stock heads, therefore lowering boost 2)then you turn up the boost and get even more flow/power

does that make sense?

Also, is there any formula to help determine what levels of boost an engine will see for given parts: ie: cfm from blower into heads with these flow numbers (I and E) to heads of this size will yield this boost level?

thanks guys

1.)so lemme ask you, these boost numbers... they are measured from a map sensor, right? (not calculated)


2.)does that make sense?

3.)Also, is there any formula to help determine what levels of boost an engine will see for given parts: ie: cfm from blower into heads with these flow numbers (I and E) to heads of this size will yield this boost level?

thanks guys

1.)Yes, map sensor. Reads in kPa, which I change to psi after adjusting for altitude and sensor calibration.

2.)Yes! You got it, makes better sense the way you say it.

3.)Not that I know of, at least not by head flow #'s. It's actually easier than that, it's HP. It takes X amount of air to make X amount of HP. Then they (ATI or your Procharger dealer) est pulley size.

I wanted my car to run mid 10's. So I figured 700 HP should do that. A 383 should make 400+ hp NA, plus one more atmosphere (14.7 psi boost) is another 400+ hp. Thats 800+ hp, less about 100 hp used to turn the blower, =700+ hp.
I then called ATI (Procharger) planning to buy a D1SC, because a D1 will make 800 hp. When I ask where I can get the best deal. The ATI rep refered me to Tony G. @ http://www.asscracing.com/ . He said go with the F1, it would have room to grow. I'm glad he did, on my first outing to the track with slicks it ran 10.50 @ 133, and right away I said ok new goal high 9's!

--Bill.

does it really take 100 hp to turn a procharger??? is that at a certain blower speed? is there an approximation to figuring that out at any speed and boost?

thanks

and also, bill, do you drive yours on the street with the slicks??

thanks

1.) does it really take 100 hp to turn a procharger??? 2.) is that at a certain blower speed? 3.) is there an approximation to figuring that out at any speed and boost?


1.) That 100 hp figure was just a guess at the time. It's probably close to that on mine at 6500 rpm and over 16#'s boost.

2.) Yes. At idle and cruise, when the surge valve is open (aka BOV), very little power is needed to turn the blower. about the same as a power steering pump.

3.) Not that I know of. This is why proper blower size is important. There can be a point of diminishing returns, when a blower is to small and it takes more power to turn it than it can make.

If I had to estimate the power needed to turn a properly sized Procharger. For 8 to 10#'s I would guess 35 to 50 hp. For 15 to 17#'s maybe 80 to 100 hp.

No, I don't use slicks on the street. I used up a pair of BFG drag radials in 600miles of street use. Now I'm using cheap street radials (Kumho 255x55x16).