On the dyno in the am

[Super73]

Putting the truck on the dyno again in the morning. Changes since last time:

Cam went from 254/260 .630/.625 111icl 112lsa to 259/274 .663/.624 109 icl 113 lsa
Gear change 4.56 to 3.90

The truck also lost 80lbs, not that that affects the dyno numbers but it slowed down NA from 10.38 @ 127 to 10.6x @ 126mph.
60' slowed from 1.53 to 1.61.
1/8 mph went from 105.x to 103.
I know different air will have an effect as well..

It did go faster than it ever has though on bottle.

Thoughts on the slow down:
Cam has more overlap and opens the exhaust valve quite a bit earlier and is much more of a N20 cam. I am guessing it moved peak TQ further up RPM making the verter even less optimized NA.
Gear also slowed 60' down.
With the glides shift extension again slowing it down more due to TQ peak and recovery
Perhaps I need to move the 1-2 shift up in RPM, the dyno will help tell me that.

I guess i will find out in the morning. If the cam doesn't make more on the bottle than last time, I will most likely switch back or try another one I have 251/266 .632/.597 108icl 112lsa.

We will see..

[BigDan3131]

Good Luck! I hope you find what your looking for so you don't have to throw money at it again.

[Hollow65]

Good luck, post the screen shot of the pull if you can please. Curious about the curve.

[Marv D]

screenshot hell.... I want VIDEO!!!

[hotrod 80]

The glide and 3.90 are hurting you .

[Super73]

Not always is bigger better.

[Super73]

Explanation on the graph. Unfortunately I could not do an overlay from previous dyno as the old PC died and files have not been moved from the old hard drive. But..

The motor previously made 520rhwp and on the same N20 tune up made 690rwhp. These numbers were corrected. So that means the new cam actually lost me 30rwhp NA and 37rwhp on the unit. I am not sure however the effect the 4.56 to 3.90 gear had.

Peak TQ was still made 5,600-5,700 rpm, however this cam seemed to make peak HP a little earlier too at about 6,700 vs my 254/260 at 6,900.

I think I am going to try the 251/266 cam I have to see what that does for me.

One thing I did confirm though is the Granatelli wires are definitely noisy. The N20 controller does not work properly when they are on the motor. I put stock wires on the motor for a NA test running a ground loop through the controller. The controller had no issues with stock wires. I will be getting a set of MSD to see if that helps the controller out.

[BR3W CITY]

What type dyno was this on?

The 60ft makes sense tho if you consider the lack of gear, converter, and new change in powerband. Being on a glide is always gonna put you at a disadvantage unless you have a way of getting way up on the stall (or being fi, or finding a way to get into the nitrous early on a progressive, or more cubes)

Are you leaving off a brake or just your foot? I feel like with that low of a gear and your glide, its gonna be a pain to get a big tire moving.

[Super73]

DynoJet

I know a 3.90 with a PG is going to sacrifice some 60' compared to the 4.56. I agree the only way to get that back would be to increase the stall speed, but that will create issue on the bottle.. Oh the lovely balancing act.

I just don't think the new cam is working well with my complete package. Perhaps it will work better with more N20, but IMO the 40rwhp drop already would be hard to make up.

One other thought I have is I forgot the rear end change. When I went from a 4.56 to 3.90 I also went from a truck 12 bolt to a 9", 31 spline axles to 35 spline, posi to locker. I could be loosing some power there too..

[Hollow65]

Maybe try some firecore wires? What size tire are you running again?

[Marv D]

Shaun,,, this is exactly why I just don't put much faith on a chassis dyno. I know it's not worth pulling the motor to put it on a engine dyno, but the chassis dyno results are too influenced by every factor from trans oil temp to the way you hold you tounge when you stomp the throttle. The only way I think you would have had real apples to apples is to chassis dyno before the rear end change. Then after.

You lost ET and MPH so I agree,, it either doesn't like the cam or the gear,,, Question is which one, or both?

Also don't I recall the 9" is WAY less efficient and takes more power to turn than the GM 12bolt? (It's just a standard because of the easy gear changes and is made strong by all of the aftermarket 'goodies') The 9" platform became a standard and so popular because of the competition in the aftermarket to make it Steve Austin (stronger, better, lighter, faster) and especially CHEAPER

[Super73]

Marv,

I am planning on sticking the 251/266 in and dynoing before going to the track on 6/20. I will try it at the track. Then I plan on sticking my old 254/260 back in for another round of dynos and a track outing in july. So by August I will have the best all around cam of the 3 I have in the motor fir the remainder of the year.

Then I have aug-oct to try and muster an 8.xx out of the truck.


I know the 9" ribs power but the rear end though should not have had an effect on peak hp rpm which the new cam seemed to have peaked a tad earlier.

[hotrod 80]

I know you don't want to hear this , but I built a small hydraulic roller deal for the white 79'Luv (which sold) . The guy had no grasp of throttle control and over revved the motor in the burnout box starving the bearings of oil and killing the crank and bearings . I built him a solid 383 with a healthy Hydraulic roller in it . I told him "shift at 6700 or he was slowing down" I also told him to put a MSD box in it with a rev limiter . About 3 weeks later he comes back telling me how strong the motor is . Truck went 10.40's on pump gas , that motor will run 8000 rpm all day long , etc . I stopped him right there and told him the motor was not built to run 8000 at all . I told him anything over 7000 occasionally was killing the motor . I told him again that he needed a rev limiter or he was gonna break it . Mind you I put serious springs on this thing . Good lifters and and valve spring parts . He came by about 2 months later complaining about how poorly the motor was built . Gaskets this , seals that , exhaust blah, blah , blah .....1 full year of flogging this thing with no rev limiter and one of the lifter retainers came off the lifter and it turned . bent push rod , bent valve . Hydraulic roller parts are heavy no 2 ways around it . I run them , but I know the limits . I ask this guy what the rev limit was set at and he told me no rev limit . I told him pound sand and that he needed a motorcycle or a formula 1 car if he wanted to rev to 14,000 . He is ready to hand me the whole truck back for .30 cents on the dollar . Sorry for the rant Solid roller and don't look back for what you are doing .

[Marv D]

Hotrod,,, hotrod ,, hotrod is there an echo echo echo in here here..here

He's gonna think so!!! LOL I've had this 'discussion' with Shaun a number of times over the years...
I'm gonna sit back with the and watch.

I know the LS guys are doing some amazing things with the hydraulic rollers,, but I just cant wrap my head around it.

[Hollow65]

You guys sound like my dad, cracking me up. Mostly hotrod.

[BR3W CITY]

Originally Posted by Marv D

I know the LS guys are doing some amazing things with the hydraulic rollers,, but I just cant wrap my head around it.

Some of the newer tech in lobe profiles and the fact that I see way more guys with beehive and double springs, meaning artificially large lift on smaller blocks, less violent ramp rates, and not nearly as many flattened cams (ask the mopar guys about that).

[Heavymetl]

Originally Posted by Marv D

Hotrod,,, hotrod ,, hotrod is there an echo echo echo in here here..here


I know the LS guys are doing some amazing things with the hydraulic rollers,, but I just cant wrap my head around it.

I attribute it to:
Larger base circle
Lightweight rockers
Good oiling
Short, light pushrods
Better valve angle
Stable non-adjustable valve train

The LS is just an all around awesome piece of engineering.

[hotrod 80]

Yes the LS is amazing , yes i drag race a hydraulic roller , yes i have had solid roller cams . I just think for a max effort build solid is the way . Street strip Hydraulic roller fits . JMO .

Hoping he gets it figured out . Alot of work going into this build for sure .

[Super73]

Old cam back in. Will have it back on the dyno in the next 1 1/2 weeks and to the track on the 20th. I know it is going to be a bit warmer at the track, so it might be a little hard to see the true effect of the rear change, but at least I will have a data point from the dyno.

I will report back.

[Kyle@FTP]

Out of curiosity why did you decide to change the rearend gears? I may have missed it while reading through.

[Super73]

7,400rpm + 4.56 + 30" radial = 132ish mph. Not enough to go 8's.

[Kyle@FTP]

Originally Posted by Super73

7,400rpm + 4.56 + 30" radial = 132ish mph. Not enough to go 8's.

Well that makes sense.

[hotrod 80]

Originally Posted by Hollow65

You guys sound like my dad, cracking me up. Mostly hotrod.

Just an opinion and probably a hypocritical one .

Just think out load here , but is this a 1.76 glide ? Thinking a 1.98 first or what ever you can get down low would be a great help if the motor can recover from the shift . Good luck with it .

[Kyle@FTP]

Originally Posted by hotrod 80

Just an opinion and probably a hypocritical one .

Just think out load here , but is this a 1.76 glide ? Thinking a 1.98 first or what ever you can get down low would be a great help if the motor can recover from the shift . Good luck with it .

or stuff a T400 in it?

[hotrod 80]

Man ......I know im gonna get hit for this one , but the turbo 400 is heavy and is a poer hog . For Alot of guys in here it is nessesity though due to weight . I haave had a 350 , 400 and a glide in my truck ( light weight ) and a glide works best for me . The 2.48 would help with a 3.90 gear though .