SBC 427 Dyno Friday HP guesses
11-02-2014, 11:49 AM
#101
Race Director
I have a question about head size (little off topic here maybe).
The difference between say a Dart Pro 1 195 head as opposed to a 215 head...Is the casting the same size throughout with just larger runners? And if so would a single cnc program be able to port both those heads to say a 220 or 230 head? I'm just curious.
The difference between say a Dart Pro 1 195 head as opposed to a 215 head...Is the casting the same size throughout with just larger runners? And if so would a single cnc program be able to port both those heads to say a 220 or 230 head? I'm just curious.
11-02-2014, 03:59 PM
#102
Team Owner
Yes, sometimes they are the same head with bigger intake ports but you can only go so far and then you have to go to a new head. I would "guess" the Pro 1 195 is a different head than the 215 as I would guess the AFR 195 is a different head than the 220. It is possible the 230 is a hogged out 220 but it is hard to tell with AFR without actually seeing the heads.
Any head requiring off set lifters or rockers is a dead give away.
When they do the competition porting SBC heads often gain 10 - 14 cc. So pauls 220 AFR with comp porting is probably very close to mid 235 cc
11-02-2014, 04:31 PM
#104
Safety Car
Thread Starter
The 600 is there , why the test was stopped at 6000 i will have an answer for Monday .. Where is your dyno sheet paul I would like to see them side by side f I could
11-02-2014, 04:44 PM
#105
Team Owner
Not a good plan. I tried both coated copper and cometic MLS .020 and they fail in under a year. You can't use the steel .015 because of aluminum heads. Aluminum expands more than the iron block so a thicker compressed to .026 or .038 work the best.
I ask Diehrd how he got the 10.5 C/R number and he never answered so the builder must not have told him piston - cc blah blah blah!
Also the highest % of power gains occur from 8.5 - 10.5 After 10.5 it is the law of diminishing returns. Because you need greater cam timing and or higher octane to keep out of detonation.
11-02-2014, 04:50 PM
#106
Safety Car
Thread Starter
Not a good plan. I tried both coated copper and cometic MLS .020 and they fail in under a year. You can't use the steel .015 because of aluminum heads. Aluminum expands more than the iron block so a thicker compressed to .026 or .038 work the best.
I ask Diehrd how he got the 10.5 C/R number and he never answered so the builder must not have told him piston - cc blah blah blah!
Also the highest % of power gains occur from 8.5 - 10.5 After 10.5 it is the law of diminishing returns. Because you need greater cam timing and or higher octane to keep out of detonation.
I ask Diehrd how he got the 10.5 C/R number and he never answered so the builder must not have told him piston - cc blah blah blah!
Also the highest % of power gains occur from 8.5 - 10.5 After 10.5 it is the law of diminishing returns. Because you need greater cam timing and or higher octane to keep out of detonation.
Also I could be wrong but what I lose in HP to paul I make up for in torque . If a dyno pulls 6% out he is 30 or 40 ft lbs below me ..
Last edited by diehrd; 11-02-2014 at 04:53 PM.
11-02-2014, 05:05 PM
#107
Le Mans Master
11-02-2014, 05:08 PM
#108
Safety Car
Thread Starter
11-02-2014, 07:06 PM
#109
Team Owner
I would need to know the bore size, head gasket thickness, cylinder deck to piston height. I played with the numbers and your compression is probably less than 10.2 and maybe as low as 9.8. Who ever told you to buy 75 cc heads did not do you a favor.
Until you find out the bore size. There is a good possibility that you have a 415 or 420 ci motor
11-02-2014, 07:58 PM
#110
Safety Car
Thread Starter
Bore:4.185
Stroke: 3.875
Cylinder Head Volume: 75cc
Effective Dome Volume:+8.5
Deck Clearance:0.00
Compressed Gasket Thickness: 0.039
Number of Cylinders: 8
Compression Ratio : 10.46 : 1
Total Displacement (in.3) : 426.43
Total Displacement cc's : 6990.66
Stroke: 3.875
Cylinder Head Volume: 75cc
Effective Dome Volume:+8.5
Deck Clearance:0.00
Compressed Gasket Thickness: 0.039
Number of Cylinders: 8
Compression Ratio : 10.46 : 1
Total Displacement (in.3) : 426.43
Total Displacement cc's : 6990.66
Last edited by diehrd; 11-02-2014 at 08:00 PM.
11-02-2014, 08:08 PM
#111
Team Owner
So you do have 427 ci. If you have .025 piston to deck which is common for new blocks your compression is @ 10.0 with 75 cc combustion chamber heads.
Your car should run fine even on 90 octane. I'm wondering if the plan was lower C/R because of your EFI. I don't know what inputs it runs off. Knock sensors have trouble with higher compressions and forged pistons. I was helping out on a 425 ci LS race motor and we had to eliminate the knock sensor because the computer was always pulling out timing
Your car should run fine even on 90 octane. I'm wondering if the plan was lower C/R because of your EFI. I don't know what inputs it runs off. Knock sensors have trouble with higher compressions and forged pistons. I was helping out on a 425 ci LS race motor and we had to eliminate the knock sensor because the computer was always pulling out timing
11-02-2014, 08:48 PM
#112
Drifting
So you do have 427 ci. If you have .025 piston to deck which is common for new blocks your compression is @ 10.0 with 75 cc combustion chamber heads.
Your car should run fine even on 90 octane. I'm wondering if the plan was lower C/R because of your EFI. I don't know what inputs it runs off. Knock sensors have trouble with higher compressions and forged pistons. I was helping out on a 425 ci LS race motor and we had to eliminate the knock sensor because the computer was always pulling out timing
Your car should run fine even on 90 octane. I'm wondering if the plan was lower C/R because of your EFI. I don't know what inputs it runs off. Knock sensors have trouble with higher compressions and forged pistons. I was helping out on a 425 ci LS race motor and we had to eliminate the knock sensor because the computer was always pulling out timing
11-02-2014, 08:50 PM
#113
Drifting
11-02-2014, 08:55 PM
#114
Drifting
Yes, sometimes they are the same head with bigger intake ports but you can only go so far and then you have to go to a new head. I would "guess" the Pro 1 195 is a different head than the 215 as I would guess the AFR 195 is a different head than the 220. It is possible the 230 is a hogged out 220 but it is hard to tell with AFR without actually seeing the heads.
My 406 is more street friendly right now than strip. i "thought" that's what I wanted but now I'm going to try and get over 650hp out of this 406.
11-02-2014, 09:05 PM
#115
Safety Car
Thread Starter
So you do have 427 ci. If you have .025 piston to deck which is common for new blocks your compression is @ 10.0 with 75 cc combustion chamber heads.
Your car should run fine even on 90 octane. I'm wondering if the plan was lower C/R because of your EFI. I don't know what inputs it runs off. Knock sensors have trouble with higher compressions and forged pistons. I was helping out on a 425 ci LS race motor and we had to eliminate the knock sensor because the computer was always pulling out timing
Your car should run fine even on 90 octane. I'm wondering if the plan was lower C/R because of your EFI. I don't know what inputs it runs off. Knock sensors have trouble with higher compressions and forged pistons. I was helping out on a 425 ci LS race motor and we had to eliminate the knock sensor because the computer was always pulling out timing
I am using EZ EFI supports 650hp ,, That is also why I was not looking for every micro gram of hp .. I want 600 with a lot of torque , I think in spite of that 6000rpm pull I am at my goal or close to it .
I do need to know it aint falling on its fact after 6000 and that all I asked for is present with the build. Over all with motorhead and other people on this forum I am feeling pretty good about it at the moment.
I may even get the motor in and twist on that 700R4 before the salt trucks and snow arrives ..
11-03-2014, 08:35 AM
#116
Drifting
Heads are too close to being maxed out on the 427 class engines. 600 HP @ 6000 is all one can expect with the selection of parts.
High end engine build. Custom cam specd by one of the best and all the other do dads but the major power maker is left up to a off the shelf universal part...
High end engine build. Custom cam specd by one of the best and all the other do dads but the major power maker is left up to a off the shelf universal part...
Remember this is a spirited driving combination. We are not trying to maximize it for an ET.
11-03-2014, 08:56 AM
#118
Drifting
This is a key statement. I see way to many times a guy say I have X amount of HP. Ok where. Well at 6800 rpm my engine makes this. Okay how do you drive. Well I dont take it pas 6000 rpm.
Don't you want the power where you drive it. Diehard's engine peak at around 6000 rpm. The torque band is within 7% of peak 1000 rpm below and a 1000 rpm above. So from 3700 to 5700 rpm the engine is within 40#/ft of max. All of this rpm is usable for the customer on a daily basis of driving.
11-03-2014, 09:10 AM
#119
Drifting
I have a question about head size (little off topic here maybe).
The difference between say a Dart Pro 1 195 head as opposed to a 215 head...Is the casting the same size throughout with just larger runners? And if so would a single cnc program be able to port both those heads to say a 220 or 230 head? I'm just curious.
The difference between say a Dart Pro 1 195 head as opposed to a 215 head...Is the casting the same size throughout with just larger runners? And if so would a single cnc program be able to port both those heads to say a 220 or 230 head? I'm just curious.