Previous Thread
Next Thread
Print Thread
Building a Procharged 6.1 #3118648
02/03/23 03:58 PM
02/03/23 03:58 PM
Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
FastmOp Offline OP
master
FastmOp  Offline OP
master

Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
Looking to see how much is needed to cut off heads and block to to gain a point of compression on a 2006 gen3 6.1 hemi.

Any help is appreciated. Anything I should worry about? Just wanting to make a reliable bracket motor I can let my friends drive.

Re: Building a Procharged 6.1 [Re: FastmOp] #3118651
02/03/23 04:02 PM
02/03/23 04:02 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 43,007
Bend,OR USA
Measure what you have and do the math scope
I wouldn't raise the compression ratio unless it is less than 7.5 to 1 ratio or worse, I would use the blow off valve, valves, to control the HP based on boost twocents
I am new to racing a supercharged motor so what do I know shruggy work

Last edited by Cab_Burge; 02/03/23 04:03 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Building a Procharged 6.1 [Re: Cab_Burge] #3118886
02/04/23 03:43 PM
02/04/23 03:43 PM
Joined: Feb 2022
Posts: 1,148
Nor here, Nor there
D
Dart 500 Offline
super stock
Dart 500  Offline
super stock
D

Joined: Feb 2022
Posts: 1,148
Nor here, Nor there
Originally Posted by Cab_Burge
Measure what you have and do the math scope
I wouldn't raise the compression ratio unless it is less than 7.5 to 1 ratio or worse, I would use the blow off valve, valves, to control the HP based on boost twocents
I am new to racing a supercharged motor so what do I know shruggy work


I dont think they run the compression that low anymore

Re: Building a Procharged 6.1 [Re: Dart 500] #3118899
02/04/23 04:42 PM
02/04/23 04:42 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 43,007
Bend,OR USA
I would verify the actual, not factory specs,. true compression ratio that motor actually has and go from there. Aren't all the 6.1 Hemi 10.0 to 1 or more stock?
The last pump gas street Hemi motor I built for a customer had right at 9.3 to 1 true mechanical compression ratio, it had a Litlefield 10:71 roots blower on it with two Carb Shop built Dominatoer carbs that were around 1050 CFM at 28.5 inches. That motor 927 HP at 7300 RPM with CA pump swill at 7.5 lbs. of boost at 12.0 percent underdriven with 33 degrees total timing using a MSD 7AL2 ignition, we switch the pulleys which made it have 13 percent overdrive and we retarded the timing to 25 degrees BTDC total and swap to Union 76 race gas with 116 octane and that motor made 1027 HP at 6500 RPM with 12.0 lbs. boost before starting to detonate and miss whiney shruggy
My point is that motor drove on the street a lot better than another pump gas blown Hemi motor for another customer that had less compression ratio and sped up the blower to make more power on the street.
Most street driving is around or under 2500 RPM in town at light part throttle so that makes the low RPM throttle response important up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Building a Procharged 6.1 [Re: FastmOp] #3118916
02/04/23 07:24 PM
02/04/23 07:24 PM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
master
polyspheric  Offline
master

Joined: Oct 2007
Posts: 4,205
New York
A centrifugal blower has minimal boost until higher RPM, compared to a Roots or axial type. The psi varies (roughly) with RPM^2: 5 psi @ 2,000 becomes 45 psi @ 6,000.
Without high stall (or a strong 1st gear) the car won't launch, and higher static CR will help, but what to do about spark at higher PSI level? MSD retard? Water injection? Be careful.
I'm going to try Snow on my turbo engine, now safe @ 17 psi, to see if leaner mixture or more spark will pick up some power.


Boffin Emeritus
Re: Building a Procharged 6.1 [Re: polyspheric] #3118926
02/04/23 08:22 PM
02/04/23 08:22 PM
Joined: Feb 2022
Posts: 1,148
Nor here, Nor there
D
Dart 500 Offline
super stock
Dart 500  Offline
super stock
D

Joined: Feb 2022
Posts: 1,148
Nor here, Nor there
The Alfa Romeo Giulia Quad has a 2.9L V6 with 9.3:1 CR and 35lbs of boost from the factory, just to show what they're doing these days. I haven't heard of anything boosted with compression down in the 7 range since the 90's. I believe even the turbo LS guys are 10.5:1

Re: Building a Procharged 6.1 [Re: Dart 500] #3118959
02/04/23 11:40 PM
02/04/23 11:40 PM
Joined: Nov 2013
Posts: 675
Southern Alberta
Uberpube Offline
mopar
Uberpube  Offline
mopar

Joined: Nov 2013
Posts: 675
Southern Alberta
The Oem's have a bunch of other stuff to consider when they build a boosted motor that aren't as much of a concern on a performance or race motor. They can't build a motor designed with a compression ratio to maximize performance with a turbo on pump gas, it would never pass modern emission standards or mileage requirements, and most people wouldn't want to drive it.

Re: Building a Procharged 6.1 [Re: Dart 500] #3118960
02/04/23 11:42 PM
02/04/23 11:42 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 43,007
Bend,OR USA
I'm still trying to decide on what compression ratio to make my new crank driven supercharged EFI E85 B1-MC heads up no prep motor, help
I'm debating between 10.5 to1 or 12.5 to 1 shruggyconfused
I'm hoping to make north of 2500 HP at or below 35 lbs. boost luck


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Building a Procharged 6.1 [Re: Cab_Burge] #3119018
02/05/23 09:50 AM
02/05/23 09:50 AM
Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
FastmOp Offline OP
master
FastmOp  Offline OP
master

Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
Cutting .010 off the heads gains how much ? Same with the block ?

I bought cheeper icon pistons off eBay but there about 9-1. I want at least 10-1.

Cab is aim for around 11-1 on your deal.

Re: Building a Procharged 6.1 [Re: FastmOp] #3119312
02/06/23 02:40 PM
02/06/23 02:40 PM
Joined: Feb 2003
Posts: 4,953
Houston, Texas
TheOtherDodge Offline
master
TheOtherDodge  Offline
master

Joined: Feb 2003
Posts: 4,953
Houston, Texas
Keep CR around 9.5:1 or it will be laggy on "off boost" driving. With aluminum heads, that will be no problem. I run that with 15 lbs of boost on pump gas, but only 17 degrees timing. With some race gas, I can increase timing (haven't tried that yet).

Re: Building a Procharged 6.1 [Re: TheOtherDodge] #3119343
02/06/23 04:19 PM
02/06/23 04:19 PM
Joined: May 2004
Posts: 12,379
Taxes & Virus's R-US, NY
Dragula Offline
I Live Here
Dragula  Offline
I Live Here

Joined: May 2004
Posts: 12,379
Taxes & Virus's R-US, NY
FBS63 is building one...

20200527_173836.jpg
Last edited by Dragula; 02/06/23 04:20 PM.

'70 Cuda,...605 EFI Hemi Street Car (6.20 best pass, 1.33 60ft)
https://www.youtube.com/watch?v=WYw6RA-k5Bk (6.25 at 108.75mph from inside car)
https://www.youtube.com/watch?v=3zQEb9uxFng (6.25 at 108mph from outside car)
https://www.youtube.com/watch?v=JCvfzsC4NgM (9.9)

'66 Barracuda AWB Stretched nose Blown 440 Car in build stage

'71 Duster Drag Car 400 Low Deck 512 best 6.002 at 115.44mph
https://www.youtube.com/watch?v=Znuo3jMUXTk
Re: Building a Procharged 6.1 [Re: Dragula] #3119441
02/06/23 10:33 PM
02/06/23 10:33 PM
Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
FastmOp Offline OP
master
FastmOp  Offline OP
master

Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
It's a small Procharger. It's max is 800HP
Had it on my SRT before they made hellcats. Sold the SRT to grow my business, but kept the Procharger. Found a doner car, having fun messing with new stuff. The SRT was 10.5-1. I'm looking for 10.

It will be in a 68 Road Runner. Bleep. Bleep!

IMG_20230205_161347340.jpg
Re: Building a Procharged 6.1 [Re: TheOtherDodge] #3119464
02/06/23 11:34 PM
02/06/23 11:34 PM
Joined: Nov 2013
Posts: 675
Southern Alberta
Uberpube Offline
mopar
Uberpube  Offline
mopar

Joined: Nov 2013
Posts: 675
Southern Alberta
You get around lag with proper gear and transmission setup. I road raced a 1.3 litre with a 72mm turbo using a close ratio dog box, lag was none existent.
Boost is compression you can cool without adding excess fuel to do it.

Re: Building a Procharged 6.1 [Re: Dragula] #3119549
02/07/23 11:27 AM
02/07/23 11:27 AM
Joined: Aug 2008
Posts: 4,049
Mo.
racerx Offline
master
racerx  Offline
master

Joined: Aug 2008
Posts: 4,049
Mo.
Originally Posted by Dragula
FBS63 is building one...

Is that one of those gen 3 hemi blocks?

Re: Building a Procharged 6.1 [Re: racerx] #3119628
02/07/23 02:44 PM
02/07/23 02:44 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 43,007
Bend,OR USA
Sure looks like one up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Building a Procharged 6.1 [Re: Cab_Burge] #3120745
02/11/23 06:25 PM
02/11/23 06:25 PM
Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
FastmOp Offline OP
master
FastmOp  Offline OP
master

Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
Been piddling.

IMG_20230211_170312755_HDR.jpg






Powered by UBB.threads™ PHP Forum Software 7.7.1