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View Full Version : How much boost on your stock motor???



juno
05-07-2007, 06:01 AM
There seems to be a trend with folks going with higher compression motors on their PA's.

The old addage was lower the compression to 8.5 or so and crank the boost.
With our stock high compression (9.85) and heavy-ass cars, we are a good sample group for longevity and performance. Our cars are generally tuned by only a handful of high quality tuners with most of them either Lidio or Scott Beer based tunes.

For those of you running a PA on a stock motor please participate in the poll.
If you would like to, please indicate your actual boost and power levels on the stock motor and trouble free S/C miles.
Or if you blew a stocker and want to share the details you can do that also. http://www.motorcitymarauders.com/forums/images/smilies/smile.gif

If you built a motor, please share your choice of compression level, boost and type of PA.
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Zack
05-07-2007, 06:07 AM
I ran 10 on a stock motor once and made 475rwhp.
A few years later I ran 14psi on a stock Ebay motor and made 525 rwhp.

The engines I have built have had 10:1 compression.
The KB makes 17psi with 10:1 and has 16 degrees of timing on 93 octane.

Rider90
05-07-2007, 06:27 AM
Stock Trilogy Kit #121 - 9.5 lbs/boost @ 390-400 RWHP. 8,000 trouble free miles so far.

MarauderTJA
05-07-2007, 06:33 AM
Jay, I ran 12 Lbs of boost with my stock motor and P1SC with 475 RWHP. With the built motor I have 9.3-1 compression, running 18 lbs boost with the D1SC at 585 RWHP on 93 octane.

Cobra25
05-07-2007, 06:52 AM
Jay, I running 11.5 lbs of Boost on a Trilogy S/C, Stock Motor, 467 RWHP & 426 RWTQ on 93 octane Pump gas. I have 12900 miles on the S/C at this time with No Problems.

juno
05-07-2007, 07:22 AM
I ran 10 on a stock motor once and made 475rwhp.
A few years later I ran 14psi on a stock Ebay motor and made 525 rwhp.

The engines I have built have had 10:1 compression.
The KB makes 17psi with 10:1 and has 16 degrees of timing on 93 octane.

What cc pistons did you use to get 10:1? Stock head volume?

DEFYANT
05-07-2007, 07:24 AM
The boost guage says 13 lbs of boost. The Marauder has been Trilogized since it had only 6000 miles. I am almost at 33K hard and fun miles. It'll run 12.0 - 12.2 all day and dip into 11.9x with some cold air. All done on pump gas - no race tune.

Zack
05-07-2007, 07:43 AM
What cc pistons did you use to get 10:1? Stock head volume?

3cc, the stock dish.

jim geary
05-07-2007, 07:59 AM
Bought car with 19,600 on it. S/c at 22,500. Getting ready to turn 27,000.
Boost varies between 9.5 and 10. Only drive occasionatly but love ever minute of it.

MarauderMark
05-07-2007, 08:28 AM
:popcorn:....

KillJoy
05-07-2007, 08:49 AM
Vortech S-Trim.

10PSI

12* of Timing

436HP / 404TQ

Stock Motor and Exhaust

~3k miles

KillJoy

sailsmen
05-07-2007, 10:08 AM
10PSI, Vortec, OEM Stock Engine, 44K S/C miles on a 40K mile engine. 447RWHP. Dynoed 20K apart and generated the same Dyno numbers.

Nothing has broke. W/ luck hoping for 100k. When she goes the plan is a OEM used motor.

I have noticed since Katrina 1/2 the time the gas is bad resulting in knocking. I have tired every major gas brand.

I use race gas at the track w/ my street tune. I recc any car w/ a power adder do the same, cheap insurance.

snowbird
05-07-2007, 12:47 PM
FIT P1SC # 5 with stock block and tranny.

Running very conservative tune for the only available fuel locally: 91 octane

9.5 pounds give about 415 RWHP and 375 RWTQ

Daily driver even in winter. Never broken or stuck on the road in over 3 years. So far, 12 000 miles N.A. and 22 000 miles on boost and still don't use any oil between oil change (syntetic only).

Marauderjack
05-07-2007, 02:14 PM
FIT....P1SC #010

I'm running from 9-10.5 PSI.....Don't know the HP but it is very adequate!!!:bows: :bows:

I currently have 57K miles on the blower install and have no oil consumption or complaints!!!:beer: :beer:

Thanks Greg & Dave for a GREAT setup!!!:D

Marauderjack:burnout:

HwyCruiser
05-07-2007, 03:35 PM
48k miles on stock motor, 13k miles on the s/c (ProCharger P1-SC 380 pulley @ 8 psi), so far no problems knock on wood.

Marauderjack
05-08-2007, 03:56 AM
48k miles on stock motor, 13k miles on the s/c (ProCharger P1-SC 380 pulley @ 8 psi), so far no problems knock on wood.

JD.....

Why the 3.8 pulley??

Isn't the one that comes with thekit a 3.7??

I think that's what I have but not sure......

Marauderjack:beer:

HwyCruiser
05-08-2007, 05:34 PM
JD.....

Why the 3.8 pulley??

Isn't the one that comes with thekit a 3.7??

I think that's what I have but not sure......

Marauderjack:beer:

I switched from the stock 3.70 to larger 3.80 pulley the first fall after the install because the DRs were useless so I was left running my stock tires. Mike thought that would make it more streetable buy dropping a couple of pounds of boost and after that I just never had the desire to go back even after it warmed up again. I think it works out great with all the other mods and the Nitto street radials. I guess it's just fast enough for me. :cool:

Todd
05-08-2007, 06:48 PM
I ran 8 psi on my stock motor making 450/502. Which of course I hurt the motor on after a really hot day and boost creep up to about 9 psi.

I had the new shortblock done at 9.2:1 and with a extremely conservative tune made 475/476 on 10psi. Will crank the timing and boost up when it has some more miles on it.

Of course I was running a turbo on the old and new motors.


If I had it to do over again, I might have done to 9.5:1 or slightly higher. The consensus is that our mod motors can take much higher compression with boost than our pushrod bretheren could/can. It has been proven time and time again on alot of the forums. Particularly the turbo mustang forums.

juno
05-09-2007, 06:15 AM
If I had it to do over again, I might have done to 9.5:1 or slightly higher. The consensus is that our mod motors can take much higher compression with boost than our pushrod bretheren could/can. It has been proven time and time again on alot of the forums. Particularly the turbo mustang forums.

Yes, that is the reason I am running the poll. My shortblock has Flattops which are around 10.2 or more. I am concerned that is too high. The builder said I can run up to 15 psi, but I do not know how much room for error there is if I get a bad tank of gas.
Well that and I would like to take a breather and run my stock block for a while.

Since it is filleted and laid out on a table in my garage, now would be a good time to swap pistons. :)
I hope to find a set of heads to just bolt on so I can do the swap motor for motor. What is the staus of your stock motor Todd? Want to sell it?
Anyone want to buy some .020 flat top manley's??

Todd
05-09-2007, 06:34 AM
Yes, that is the reason I am running the poll. My shortblock has Flattops which are around 10.2 or more. I am concerned that is too high. The builder said I can run up to 15 psi, but I do not know how much room for error there is if I get a bad tank of gas.
Well that and I would like to take a breather and run my stock block for a while.

Since it is filleted and laid out on a table in my garage, now would be a good time to swap pistons. :)
I hope to find a set of heads to just bolt on so I can do the swap motor for motor. What is the staus of your stock motor Todd? Want to sell it?
Anyone want to buy some .020 flat top manley's??



PM Sent...

greggash
05-09-2007, 10:22 AM
well... my car is a centrifugal (DR Vortech)
I push about 8-9 lbs of boost

my Horsepower is 455 RWHP so mine does not fall into your charts

More horsies....less boost......

superford3
05-09-2007, 12:15 PM
this is a very good read,i dont have boost but i run spray ,my car put down 380hp and 463.tq with a 125 shot and since then im running 150 shot ,i have been wondering how much power people have been running reliable so very good thread

LILALLEYKATT
05-11-2007, 08:26 PM
I just got my 302 stroker together using a Kellog crank Eagle rods, Eagle pistons all forged of course. Ported heads. 9.8 compression. I see 16 pounds boost in the southern heat and 17 pounds on a cool northern morning. Meth injection tops it off. The torque is amazing as it pulls like a built big block. Still breaking it in with a very conservative tune. I am sure that this setup is capable of mid 11's when the tune is dialed up. :cool:

MarauderTJA
05-12-2007, 06:21 AM
I just got my 302 stroker together using a Kellog crank Eagle rods, Eagle pistons all forged of course. Ported heads. 9.8 compression. I see 16 pounds boost in the southern heat and 17 pounds on a cool northern morning. Meth injection tops it off. The torque is amazing as it pulls like a built big block. Still breaking it in with a very conservative tune. I am sure that this setup is capable of mid 11's when the tune is dialed up. :cool:

Great job:up: Mid-11's should be no problem. With all that power your problem, like mine along with the other guys with built motors, will be hooking up. But when you do, hold on for the ride of your life. The rush is better than sex (well amost). Hope you are going to make SSHS7 with your new beast. We need to show the Impala boys that Marauders can kick butt.:burnout:Looking forward to seeing your numbers once you get her broken in and on the dyno.