Went to the dyno today!
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 6,595
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From: Thornton CO
Went to the dyno today!
I took my car to the dyno today - looks like I still need a lot of tuning.
I have an exhaust leak so I'm wondering how much that is affecting me, plus I didn't port my intake manifold for the 58mm Throttle Body yet so I still have some work to do!
335.5 HP
364.7 lb/ft torque
http://sitesbytim.com/Pictures/Corvette/dyno.htm
Here's a link to my dad's Grand Sport (#5) he just has a K&N and cut air lid:
http://sitesbytim.com/Pictures/Corvette/dyno-dad.htm
Tim
I have an exhaust leak so I'm wondering how much that is affecting me, plus I didn't port my intake manifold for the 58mm Throttle Body yet so I still have some work to do!
335.5 HP
364.7 lb/ft torque
http://sitesbytim.com/Pictures/Corvette/dyno.htm
Here's a link to my dad's Grand Sport (#5) he just has a K&N and cut air lid:
http://sitesbytim.com/Pictures/Corvette/dyno-dad.htm
Tim
Race Director
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Posts: 14,165
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Re: Went to the dyno today! (I_HATE_Mustangs)
Yeah man I could say you need some tuning. I made very comprable numbers with my 350 which still has stock heads. You've got me beat more in torque than in HP, but it's still very close. I'm sure you can take me, but it wouldn't be the stomping I would expect from a 383. Something is screwing with your dyno charts, they shouldn't be so rough.
Here are my charts, notice how smooth they are :) http://24.17.202.123/htmls/dyno_corvette.html
You are well on your way, some more tuning and tweaking and you'll have a beast. I wish I had a stroker, but I don't want to blow up my motor. I can't afford the stroker or the downtime. :sad:
Here are my charts, notice how smooth they are :) http://24.17.202.123/htmls/dyno_corvette.html
You are well on your way, some more tuning and tweaking and you'll have a beast. I wish I had a stroker, but I don't want to blow up my motor. I can't afford the stroker or the downtime. :sad:
Drifting
Joined: Nov 2000
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From: Big D Tx
Cruise-In II Veteran
Re: Went to the dyno today! (I_HATE_Mustangs)
it looks like you might have a tad bit of timing pulled out by the PCM due to slight detonation or your spark is shorting to ground. your curve should be as smooth as your dads GS. when was the last time you changed plugs and wires. also, your right it could be the exaust leak, depending where the leak is at.
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 6,595
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From: Thornton CO
Re: Went to the dyno today! (88L98)
I do need to pull the plugs and take a look at them especially after running the car super lean for 4,000 miles! I ran TTS Datamaster at the same time as the dyno run and it's pulling as much as 10 degrees of timing out because it's detecting some sort of "knock". I only have 9.8:1 compression so it's most likely not the gas causing knock.
Don't forget that I have an Automatic! I get robbed of 20% of my power instead of 15% to the 6 speed.
Don't forget that I have an Automatic! I get robbed of 20% of my power instead of 15% to the 6 speed.
Race Director
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Re: Went to the dyno today! (I_HATE_Mustangs)
Don't forget that I have an Automatic! I get robbed of 20% of my power instead of 15% to the 6 speed.
Why only 9.8:1 compression? Do I hear a supercharger or a turbo spooling up in your future?
[Modified by Nathan Plemons, 6:12 PM 2/9/2002]
[Modified by Nathan Plemons, 6:12 PM 2/9/2002]
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 6,595
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From: Thornton CO
Re: Went to the dyno today! (Nathan Plemons)
Why only 9.8:1 compression? Do I hear a supercharger or a turbo spooling up in your future?
Actually my engine builder did that because of the altitude and I mentioned some NOS or a charger in there too so he went conservative for the short term. Ya just never know when I'm going to get the urge (and some money)!
Race Director
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Re: Went to the dyno today! (I_HATE_Mustangs)
(and some money)!
I hear you there. I need heads, then I'll try to save up for a supercharger. Then when I blow it up I'll be forced to build a completely forged stroker. Probably a 396. I don't know why I just like the way that looks better than 383, although performance is probably VERY comprable.
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 6,595
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From: Thornton CO
Re: Went to the dyno today! (Nathan Plemons)
I didn't think I had the money for a stroker motor until I spun a couple of bearings and all of the sudden I was *forced* to build it! Actually it probably onl cost me about $500 more than a performance rebuild.
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From: Little Elm TX
Re: Went to the dyno today! (I_HATE_Mustangs)
You have a LOT of power left in tuning with your set-up.... looks like it came off the converter by 4500 rpm and pulled to 5000 rpm and then just completely coughed..... your LT-1 curve should continue to pull up to roughly 6000 rpm depending on your cam specs..... I would think you have a solid 50rwhp missing.... thats a lot !!!
Whats your cam specs ? Whats your converter ? Are you running a single main cat ?
The good news.... you get to have fun finding it. :)
good luck
Beach Bum
Whats your cam specs ? Whats your converter ? Are you running a single main cat ?
The good news.... you get to have fun finding it. :)
good luck
Beach Bum
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 6,595
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From: Thornton CO
Re: Went to the dyno today! (Beach Bum)
Cam is 216/226 - 508/534, 114LSA
Converter is stock. Dual cats (104k miles on them) with SLP shorty headers.
I'm thinking the non-ported intake manifold (where the TB mounts) may have something to do with the dropoff as well.
Forgot the most important detail - Spark knock - bad! Pulling out 10 degrees at 3500rpm and knocks all the way to redline. Could be a bad knock sensor or could be the exhaust leak fooling the knock sensor.
[Modified by I_HATE_Mustangs, 5:31 PM 2/9/2002]
[Modified by I_HATE_Mustangs, 5:32 PM 2/9/2002]
Converter is stock. Dual cats (104k miles on them) with SLP shorty headers.
I'm thinking the non-ported intake manifold (where the TB mounts) may have something to do with the dropoff as well.
Forgot the most important detail - Spark knock - bad! Pulling out 10 degrees at 3500rpm and knocks all the way to redline. Could be a bad knock sensor or could be the exhaust leak fooling the knock sensor.
[Modified by I_HATE_Mustangs, 5:31 PM 2/9/2002]
[Modified by I_HATE_Mustangs, 5:32 PM 2/9/2002]
Race Director
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Re: Went to the dyno today! (I_HATE_Mustangs)
I don't think that would be as much of a problem as you think. Remember that the ports on the intake are actually 52, so you have the equivilent of a 52mm TB on there. It may be holding you back some but I don't think it should cause such a dropoff.
I wonder what it could be picking up as knock? That's gotta be a lot of it.
Ah, edit your post while I post, thus making me edit my post. I would check out that exhaust leak, if it's bad enough it could be your trouble. I have a small exhaust leak in the cat-back, but it isn't enough for the computer to pick up on. Who did your computer work? You do have to turn down your knock sensitivity a little with a cam and roller rockers.
[Modified by Nathan Plemons, 6:35 PM 2/9/2002]
I wonder what it could be picking up as knock? That's gotta be a lot of it.
Ah, edit your post while I post, thus making me edit my post. I would check out that exhaust leak, if it's bad enough it could be your trouble. I have a small exhaust leak in the cat-back, but it isn't enough for the computer to pick up on. Who did your computer work? You do have to turn down your knock sensitivity a little with a cam and roller rockers.
[Modified by Nathan Plemons, 6:35 PM 2/9/2002]
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 6,595
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From: Thornton CO
Re: Went to the dyno today! (Nathan Plemons)
I'm doing all of the computer work - haven't heard of "turning down the sensor" though.
I actually have 2 exhaust leaks on the drivers side. 1) the header won't seal and 2) one of the bolts that holds the cat to the exhaust broke.
Here's a datamaster log of the dyno runs for all of those tuners out there:
http://sitesbytim.com/pictures/corve...gs/timrun9.uni
I actually have 2 exhaust leaks on the drivers side. 1) the header won't seal and 2) one of the bolts that holds the cat to the exhaust broke.
Here's a datamaster log of the dyno runs for all of those tuners out there:
http://sitesbytim.com/pictures/corve...gs/timrun9.uni
Race Director
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Re: Went to the dyno today! (I_HATE_Mustangs)
Ok, here is something you can try. Look on the back of the computer, see if there is a little panel back there, if there is remove it and see if there is a chip you can pull out, if so this is your knock module. You can get an LT4 knock module which is a lot less sensitive. You might can program it in the computer as well, I'm just not sure how it all works. Everybody I know who has that type of computer who has a cam has also had to get the knock module. This may be because they are too cheap to get the computer programmed properly. It might be something that you don't need if you can program the computer, I just really don't know.
Le Mans Master
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From: Chino Valley AZ
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Currently Corvette-less
Re: Went to the dyno today! (I_HATE_Mustangs)
Tim,
Dyno'd mine yesterday. 92 LT1 Coupe (automatic). 115K miles. I have the SVO FMS 24#/hr injectors, Performance Resource Chip, and airfoil. My numbers were:
1st Pull
251.7 @ 290.0 torque
2nd Pull
254.7 @ 293.6 torque
Dyno'd mine yesterday. 92 LT1 Coupe (automatic). 115K miles. I have the SVO FMS 24#/hr injectors, Performance Resource Chip, and airfoil. My numbers were:
1st Pull
251.7 @ 290.0 torque
2nd Pull
254.7 @ 293.6 torque
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 6,595
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From: Thornton CO
Re: Went to the dyno today! (PurpleC4)
1st Pull
251.7 @ 290.0 torque
2nd Pull
254.7 @ 293.6 torque
251.7 @ 290.0 torque
2nd Pull
254.7 @ 293.6 torque
Pro
Joined: Jun 2001
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From: College Station Tx
Re: Went to the dyno today! (I_HATE_Mustangs)
Porting the intake may help some - it depends on how the intake ports on your heads look. Your goal is to basically have a taper from intake inlet in the plun down to the valve back. If you port match it yourself it isn't to difficult - just make sure not to make the mistake of porting the intake outside much larger then the intake inlet (runner near the plenum) - this gives you a small to large to small transition which probably won't help to much. If you raise the roof a little that can generally help.
Looking at your runs the knock retard is obviously an issue. You seem to have a handle on the l-trims, but I still think the ported MAF may be causing problems - is there anyone you could borrow a stock maf from (Descrenned is okay) to test out? This may cure some of your spark retard problems.
Looking at your runs the knock retard is obviously an issue. You seem to have a handle on the l-trims, but I still think the ported MAF may be causing problems - is there anyone you could borrow a stock maf from (Descrenned is okay) to test out? This may cure some of your spark retard problems.
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 6,595
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From: Thornton CO
Re: Went to the dyno today! (ChrisB)
I still have my stock MAF sensor. I will put it back in and then reset my MAF table back to stock (vs the 115% scaling you told me to try). The Lterms look perfect, just gotta get rid of that knock.
Also - when I say port the intake I am talking about the holes for the Throttle Body.
Thanks Chris - you've been a big help!
Tim
Also - when I say port the intake I am talking about the holes for the Throttle Body.
Thanks Chris - you've been a big help!
Tim