lowering compression
- Thread starter stud_rudd
- Start date
The people who are telling you to lower the compression that much are behind the times. 9 to 1 or 9.5 to 1 on gas will allow you make your power easier, as you can turn the blower slower and have less heat in the gas mixture.
Depending on where you are, have you considered using e-85? Can you get it easy? You may be able to run the compresion you have now.
Call BDS or the Blower shop and see what they say.
Depending on where you are, have you considered using e-85? Can you get it easy? You may be able to run the compresion you have now.
Call BDS or the Blower shop and see what they say.
Cookieman
New member
Look at the video of my motor. I think it was under "the motor is back in the boat". I have a 454 30 over with 8 to 1 pistons, intercooler and 420 mega blower, 2 750 "blower"carbs. simple unilite distribytor with petronics guts. The motor starts easy and has a nice cam which I can't remember with solid roller lifters with roller rockers. Motor starts so easy I just can't believe it.Make sure you have a large oil pan because blower motors build up a lot of heat
duanehydro
Active member
are your pistons flattop?
duanehydro
Active member
ummm..that's a dish......if you are using 72cc heads, that's what you have to change...
More information needed.
More information on boat and how much power do you want to make? I was running 9.3 to 1 compression using AV gas with about 9.5 LBS boost. It was under-driven 5% and worked well, but I have a 14-71 blower.
The slower you are able to turn the blower and still get the boost you want without detonation the easier it is on everything. BDS has a chart out that will give a ballpark figure about the boost you can run with pump gas or race gas. Go to their web site or get their catalog for the chart. A lot can be adjusted with blower pulley combinations that will change the boost levels you can run for different size motors.
I have recently switched to e85 and it is my understanding that I can increase the boost because of the cooling effect alcohol has with a blower. With just changing the carburetors metering blocks and boosters and no other changes, the power was about the same. I have not tested after re-jetting, but I think there should be more power with no other change.
More information on boat and how much power do you want to make? I was running 9.3 to 1 compression using AV gas with about 9.5 LBS boost. It was under-driven 5% and worked well, but I have a 14-71 blower.
The slower you are able to turn the blower and still get the boost you want without detonation the easier it is on everything. BDS has a chart out that will give a ballpark figure about the boost you can run with pump gas or race gas. Go to their web site or get their catalog for the chart. A lot can be adjusted with blower pulley combinations that will change the boost levels you can run for different size motors.
I have recently switched to e85 and it is my understanding that I can increase the boost because of the cooling effect alcohol has with a blower. With just changing the carburetors metering blocks and boosters and no other changes, the power was about the same. I have not tested after re-jetting, but I think there should be more power with no other change.
Here is everything i know about my boat and engine AND what i would like to accomplish with it.
1976 Sanger Super Jet 533 Cubic Inch Ford Stroker Engine Eagle stroker crank, H beam Rods, JE Pistons, ARP Stud Kit Edelbrock aluminum heads, Hyd Lifters & Cam, Prop Comp roller rockers, Pete Jackson Gear Drive, MSD Billet Dist& Ignition with Soft touch rev control, Hot Foot pedal Offey Tunnel Ram with dual 750 Edelbrocks Engine machined and assembled by McMurtrys Racing Engines. Pump rebuilt by Hi-Tech Performance it has 9 Vein Split Bowl A-2 Impeller The Snoot with 2 wedges and Hydraulic Place Diverter with steering wheel control.
The man who put together the engine says it should produce around 632 HP. I love the look of a massive engine. Esp. a blower. Im not into racing it. I want to the engine to produce 1000+ HP. I am totally set on a blower, i'm just not very knowledgable on engines, esp. blowers and such. I talked with Don hampton and a few People from 460Ford.com and they all tell me my components are good except the cam and compression asspect.
My compression now (as far as I know, according to the machinest) is around 9.5-10:1. If it is that high, could i just run ethanol? THank you
1976 Sanger Super Jet 533 Cubic Inch Ford Stroker Engine Eagle stroker crank, H beam Rods, JE Pistons, ARP Stud Kit Edelbrock aluminum heads, Hyd Lifters & Cam, Prop Comp roller rockers, Pete Jackson Gear Drive, MSD Billet Dist& Ignition with Soft touch rev control, Hot Foot pedal Offey Tunnel Ram with dual 750 Edelbrocks Engine machined and assembled by McMurtrys Racing Engines. Pump rebuilt by Hi-Tech Performance it has 9 Vein Split Bowl A-2 Impeller The Snoot with 2 wedges and Hydraulic Place Diverter with steering wheel control.
The man who put together the engine says it should produce around 632 HP. I love the look of a massive engine. Esp. a blower. Im not into racing it. I want to the engine to produce 1000+ HP. I am totally set on a blower, i'm just not very knowledgable on engines, esp. blowers and such. I talked with Don hampton and a few People from 460Ford.com and they all tell me my components are good except the cam and compression asspect.
My compression now (as far as I know, according to the machinest) is around 9.5-10:1. If it is that high, could i just run ethanol? THank you