427ci small block says hello to 7000RPM on the chassis dyno
04-28-2010, 09:49 PM
#1
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427ci small block says hello to 7000RPM on the chassis dyno
Well it was a good day. I am happy, the little mouse pulls like a freight train to 7000 RPM. I will admit I didn't make my HP goal but this was just one base run, absolutely no tuning, not even a timing adjustment.
I knew the headers would hold me back above 6500RPM, like having a nice big block with 1 3/4" headers, ain't gonna work. I wasn't off by far an tuning could get me there but I did this because I want to just change to the new 1 7/8" stainless without any other changes to see the difference and I bet there's gonna be a few more ponies up top.
My Vette is verified as 23% power loss from engine dyno to rear wheel chassis dyno, as I have removed my old 406ci and put it on an engine dyno then right back in and put it on a chassis dyno.
This is to 7000RPM. MagnaFlow mufflers, I know a little on the quiet side so crank it up Rear tire speed was 186 mph, the dyno shuts down at 200mph
I knew the headers would hold me back above 6500RPM, like having a nice big block with 1 3/4" headers, ain't gonna work. I wasn't off by far an tuning could get me there but I did this because I want to just change to the new 1 7/8" stainless without any other changes to see the difference and I bet there's gonna be a few more ponies up top.
My Vette is verified as 23% power loss from engine dyno to rear wheel chassis dyno, as I have removed my old 406ci and put it on an engine dyno then right back in and put it on a chassis dyno.
This is to 7000RPM. MagnaFlow mufflers, I know a little on the quiet side so crank it up Rear tire speed was 186 mph, the dyno shuts down at 200mph
Last edited by MotorHead; 04-29-2010 at 08:20 PM.
04-28-2010, 10:02 PM
#3
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04-28-2010, 10:32 PM
#6
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Alright I can't take it anymore I was shooting for 500RWHP and got 478 RWHP and 448 RWT. I will make the 500 with the bigger headers I am sure.
I also have some stupid Car Chemistry baffles inserted right into the pipes to quiet the car down. That can't be helping either. But like I said I am happy and should be well over 500RWHP buy the time I am finished
I also have some stupid Car Chemistry baffles inserted right into the pipes to quiet the car down. That can't be helping either. But like I said I am happy and should be well over 500RWHP buy the time I am finished
04-28-2010, 10:53 PM
#11
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Well it was a good day. I am happy, the little mouse pulls like a freight train to 7000 RPM. I will admit I didn't make my HP goal but this was just one base run, absolutely no tuning, not even a timing adjustment.
I knew the headers would hold me back above 6500RPM, like having a nice big block with 1 3/4" headers, ain't gonna work. I wasn't off by far an tuning could get me there but I did this because I want to just change to the new 1 7/8" stainless without any other changes to see the difference and I bet there's gonna be a few more ponies up top.
My Vette is verified as 23% power loss from engine dyno to rear wheel chassis dyno, as I have removed my old 406ci and put it on an engine dyno then right back in and put it on a chassis dyno.
Now I can go ahead an tell you or you guys can guess the HP and TQ and I'll tell you tomorrow, whatever, I kinda like the guessing thing more so when it not even mine. The winner gets a banana sandwich for HP and potato chip hot dog for the Tq.
This is to 7000RPM, I'll shorten it when I get the time or you can just shut if off after the pull. MagnaFlow mufflers, I know a little on the quiet side so crank it up :cheers:
I knew the headers would hold me back above 6500RPM, like having a nice big block with 1 3/4" headers, ain't gonna work. I wasn't off by far an tuning could get me there but I did this because I want to just change to the new 1 7/8" stainless without any other changes to see the difference and I bet there's gonna be a few more ponies up top.
My Vette is verified as 23% power loss from engine dyno to rear wheel chassis dyno, as I have removed my old 406ci and put it on an engine dyno then right back in and put it on a chassis dyno.
Now I can go ahead an tell you or you guys can guess the HP and TQ and I'll tell you tomorrow, whatever, I kinda like the guessing thing more so when it not even mine. The winner gets a banana sandwich for HP and potato chip hot dog for the Tq.
This is to 7000RPM, I'll shorten it when I get the time or you can just shut if off after the pull. MagnaFlow mufflers, I know a little on the quiet side so crank it up :cheers:
I must say you built one hell of a motor
, nice to see the old school guys are still alive and well.
Rob.
04-28-2010, 11:01 PM
#12
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What were the RPM peaks? Great numbers!
JIM
JIM
04-28-2010, 11:29 PM
#14
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Tires are OK they are ZR rated I think I was under 200mph but not by much, gotta calculate that
04-28-2010, 11:54 PM
#15
You can believe anything you want at least I took the time to actually do it. Of course you don't have a full exhaust on the motor, it's an engine dyno, doesn't even have a or alternator to drive, you are measuring what the motor puts out with nothing taking any power away it's call GROSS HP
Tires are OK they are ZR rated I think I was under 200mph but not by much, gotta calculate that
Tires are OK they are ZR rated I think I was under 200mph but not by much, gotta calculate that
04-29-2010, 12:00 AM
#16
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04-29-2010, 12:03 AM
#17
When you did the test with your old 406, right back in after the engine dyno as you said, you made 23% less power, right? Was that with a full exhaust? If so, then some of that percentage is due to the full exhaust, no doubt.
If you ran it open exhaust, then I stand corrected. But 23% seems pretty damn high for a manual trans car. Especially one with a modern manual trans.
If you ran it open exhaust, then I stand corrected. But 23% seems pretty damn high for a manual trans car. Especially one with a modern manual trans.
04-29-2010, 12:10 AM
#19
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Here's the printouts, the power drops off after 6500 but everyone seemed to agree the headers where choking it.
You can see here it starts to go lean at 6500 an indication of something choking it off
You can see here it starts to go lean at 6500 an indication of something choking it off
04-29-2010, 12:15 AM
#20
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When you did the test with your old 406, right back in after the engine dyno as you said, you made 23% less power, right? Was that with a full exhaust? If so, then some of that percentage is due to the full exhaust, no doubt.
If you ran it open exhaust, then I stand corrected. But 23% seems pretty damn high for a manual trans car. Especially one with a modern manual trans.
If you ran it open exhaust, then I stand corrected. But 23% seems pretty damn high for a manual trans car. Especially one with a modern manual trans.
I at least spent the money and time to do the test and that is what it worked out for my Vette others are probably higher I doubt many C3's are much lower
Last edited by MotorHead; 04-29-2010 at 12:20 AM.