Dyno numbers
Thread Starter
Team Owner
Joined: Apr 2001
Posts: 22,267
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From: Dallas TX
Dyno numbers
I haven't really used Desktop Dyno much. Do these numbers seem right? I wasn't really expecting this much of a gain out of the 383 upgrade.
I'm guessing on the 11:1 compression because that's what I'm looking for (or somewhere close to that like 10.8 or so).
I'm also not sure what type of heads the LT1's are based on what to chose from. I picked pocket porting (because hopefully I'll be able to do that). I assume pocket porting is just opening up the intake, exhaust, and the area around the valves that the air comes in and goes out.
Also, my dyno before any engine work at all (like what's being done right now) was 275hp and 307tq at the wheels...
[Modified by Glock'94, 2:19 AM 12/14/2001]
I'm guessing on the 11:1 compression because that's what I'm looking for (or somewhere close to that like 10.8 or so).
I'm also not sure what type of heads the LT1's are based on what to chose from. I picked pocket porting (because hopefully I'll be able to do that). I assume pocket porting is just opening up the intake, exhaust, and the area around the valves that the air comes in and goes out.
Also, my dyno before any engine work at all (like what's being done right now) was 275hp and 307tq at the wheels...
[Modified by Glock'94, 2:19 AM 12/14/2001]
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: Dyno numbers (Glock'94)
That looks somewhat like the curve from a 383 with mini-ram in TPIS "Insider Hints". Your higher numbers may be due to the pocket porting.
I noticed that you still have stock valve sizes; you might want to see what larger valves (2.00/1.56) do for you. Also, play with the exhaust system a little.
If you want to plug those numbers into Drag2000 to optomize your ET try about 85% of the Dyno2000 HP curve numbers. I have recent dyno pulls and time slips and this is what I had to do to get the correct trap speed. Then I had to massage the slippage a little to get current ET. From there you can optomize TC stall and shift points for best ET.
We realy have some interesting design tools to work with these days.
I noticed that you still have stock valve sizes; you might want to see what larger valves (2.00/1.56) do for you. Also, play with the exhaust system a little.
If you want to plug those numbers into Drag2000 to optomize your ET try about 85% of the Dyno2000 HP curve numbers. I have recent dyno pulls and time slips and this is what I had to do to get the correct trap speed. Then I had to massage the slippage a little to get current ET. From there you can optomize TC stall and shift points for best ET.
We realy have some interesting design tools to work with these days.
Le Mans Master
Joined: Oct 1999
Posts: 9,713
Likes: 3
From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: Dyno numbers (65Z01)
From the way I read it, your cam specs look wrong (is it looking for total duration or at .050, plus the Hotcam is on a 110 not a 108), you have listed it as a roller cam rather than a hydrolic roller, your showing a 70 or 78 (can't tell) combustion volume when I think that should be smaller. never used teh program so I may be wrong though.
Burning Brakes
Joined: Dec 2000
Posts: 1,023
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From: Marietta, South Carolina, USA
Re: Dyno numbers (Glock'94)
I dont think you will see that much gain.
You gain about 25tq and 2-3hp with just a 383 change but since you are doing the head work and a cam too it will go up more.
From the info you have on here I think you will have about 385tq and 379hp but that is with a mild port job maybe 10% more flow and the HotCam and full exhaust, but then again you have to take 15% of that to get the RW numbers.
I see that you have a open exhause in the dyno run that will help you a lot but when you have the hole system the numbers will go down.
Keep us posted
Jay
You gain about 25tq and 2-3hp with just a 383 change but since you are doing the head work and a cam too it will go up more.
From the info you have on here I think you will have about 385tq and 379hp but that is with a mild port job maybe 10% more flow and the HotCam and full exhaust, but then again you have to take 15% of that to get the RW numbers.
I see that you have a open exhause in the dyno run that will help you a lot but when you have the hole system the numbers will go down.
Keep us posted
Jay
Thread Starter
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: Dyno numbers (Vette92)
From the way I read it, your cam specs look wrong (is it looking for total duration or at .050, plus the Hotcam is on a 110 not a 108), you have listed it as a roller cam rather than a hydrolic roller, your showing a 70 or 78 (can't tell) combustion volume when I think that should be smaller. never used teh program so I may be wrong though.
and, btw, it won't let me chose hydraulic roller for cam.. hmm.....
and, I just typed in the compression ratio instead of calculating it out with the volumes.
[Modified by Glock'94, 3:00 PM 12/14/2001]
Le Mans Master
Joined: Oct 2001
Posts: 5,302
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From: Atlanta GA
Re: Dyno numbers (Glock'94)
[QUOTE
and, btw, it won't let me chose hydraulic roller for cam.. hmm.....
and, I just typed in the compression ratio instead of calculating it out with the volumes.[/QUOTE]
Desktop dyno does not distinguish between hydraulic roller and solid roller, it is a combined selection.
I am not an LT-1 guy, but TECHNICALLY isn't an LT-1 a tuned port injection setup? I ask this because you selected sequential fire injection. Just something else that might need changing :confused:
I'm still learning how to use it, I just picked it up last wednesday. Good luck!
:cheers:
and, btw, it won't let me chose hydraulic roller for cam.. hmm.....
and, I just typed in the compression ratio instead of calculating it out with the volumes.[/QUOTE]
Desktop dyno does not distinguish between hydraulic roller and solid roller, it is a combined selection.
I am not an LT-1 guy, but TECHNICALLY isn't an LT-1 a tuned port injection setup? I ask this because you selected sequential fire injection. Just something else that might need changing :confused:
I'm still learning how to use it, I just picked it up last wednesday. Good luck!
:cheers:
Safety Car
Joined: Mar 2000
Posts: 3,620
Likes: 2
From: Hillsboro OR
Re: Dyno numbers (Glock'94)
You've got some settings that are wrong for your engine.
The intake should be tunnel ram because its closest to the LT1 style intake. SFI is the superram. Exhaust should be small tubes with headers. Hot cam lobe center is 112. HP goes up as this number gets smaller but part throttle and lowend power goes down as well. Do the cam timing @ .050. The seat to seat varies widely between cam mfrs and will give you really inaccurate results. I have not seen anybody give the intake center of lift for the hot cam. Its probably between 108 - 112.
Head flow is tricky. AFR has an article that shows the airlflow for a bunch of heads including the LT1. Use those numbers for the head. Be sure you set the flow rate to match the one used in the test. Pocket porting should increase flow about 10% across the board.
The intake should be tunnel ram because its closest to the LT1 style intake. SFI is the superram. Exhaust should be small tubes with headers. Hot cam lobe center is 112. HP goes up as this number gets smaller but part throttle and lowend power goes down as well. Do the cam timing @ .050. The seat to seat varies widely between cam mfrs and will give you really inaccurate results. I have not seen anybody give the intake center of lift for the hot cam. Its probably between 108 - 112.
Head flow is tricky. AFR has an article that shows the airlflow for a bunch of heads including the LT1. Use those numbers for the head. Be sure you set the flow rate to match the one used in the test. Pocket porting should increase flow about 10% across the board.
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From: Hacienda Heights, Ca. USA
Re: Dyno numbers (AquaMetallic94LT1)
I put the LT4 Hotcam specs on my Desktop Dyno for my '88 L98 with CNC ported head flow numbers and got 410hp @ 5500 rpm, & 471tq @ 3500 rpm. That's figuring with the stock tpi setup. I'll tell you from firsthand driving experience that this car flat out hauls butt! I have 315's for the rear tires and it'll fry them on demand. I have a ZR1 and I really believe that my ZR1 would have to play catch up. I just blew the transmission on Monday this week when fellow forum member "Drive it" and I were doing some chip tuning, and under a WOT blast I lost 3rd & 4th gear. I'll be getting a new beefed up trans in the next couple of weeks and then I'll put it on a dyno and post the numbers. I say that for the money the LT4 Hotcam delivers!
Thread Starter
Team Owner
Joined: Apr 2001
Posts: 22,267
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From: Dallas TX
Re: Dyno numbers (john25)
Wow.. good to hear John :) Those numbers with the L98, i should be doing a little better with the LT1. Perhapse i'm not too far off with the dyno curve (i corrected some things on it) .. except the transmission part of course. I'm gonna have to take it a little easy so that i don't blow my transmission. That's not an expense i would like to have to deal with right after paying for the motor.