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Discussion Starter #1
Well, I had the LPE GT 2-3 cam installed about 6 weeks ago and today I finally had an opportunity to have it retuned on the dyno. To put it mildly, Im a bit frusterated as to why my numbers are so much lower than others with the same less/mods and cam!?!?

The retune was at MTI (Motorsport Technologies Inc) in Houston and done by Jayson (GREAT guy!). They are known worldwide for high quality and I am confident he did all he could. I am just po'd that I got a skunk cam and or motor. :hissy:

Ill try to post the dyno sheet shortly since it shows the run precam and post cam together but below are the results.

Pre Tune / Post Tune
350 RWHP / 357 RWHP + 7 RWHP
362 RWTQ / 370 RWTQ + 8 RWTQ

I didnt pay good money for 7HP. Wait, yes I did! :duh:

These numbers also include the addition of a ported LS7TB after the cam install. Now I dont expect major gains from the ported tb but if you could consider 1-2 HP gain from that alone in most cases, does that mean the cam gave me 5-6HP. WTF!?!?!

Sorry for the rant! Had to vent somewhere!!!!!!!!
 

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Where was the base dyno run done? At MTI as well? The first dyno run may have been very generous.

Anyways, I think the biggest thing hurting you is that you don't have long tube headers. You will never get the full potential of a cam if you can't get that extra air out. I would always recommend to someone that they get headers first before they do a cam swap and/or heads.
 

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Numbers dont mean much hate to say it, I have big Dyno numbers and I ran a 13.11 at 209.99 (1/3 tank of gas)
:eek: Problems hooking up :undecided


Well, I had the LPE GT 2-3 cam installed about 6 weeks ago and today I finally had an opportunity to have it retuned on the dyno. To put it mildly, Im a bit frusterated as to why my numbers are so much lower than others with the same less/mods and cam!?!?

The retune was at MTI (Motorsport Technologies Inc) in Houston and done by Jayson (GREAT guy!). They are known worldwide for high quality and I am confident he did all he could. I am just po'd that I got a skunk cam and or motor. :hissy:

Ill try to post the dyno sheet shortly since it shows the run precam and post cam together but below are the results.

Pre Tune / Post Tune
350 RWHP / 357 RWHP + 7 RWHP
362 RWTQ / 370 RWTQ + 8 RWTQ

I didnt pay good money for 7HP. Wait, yes I did! :duh:

These numbers also include the addition of a ported LS7TB after the cam install. Now I dont expect major gains from the ported tb but if you could consider 1-2 HP gain from that alone in most cases, does that mean the cam gave me 5-6HP. WTF!?!?!

Sorry for the rant! Had to vent somewhere!!!!!!!!
What did the butt dyno say? Did you feel more performance after the new cam?

Maybe the cam installed backwards? j/k
 

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Discussion Starter #5
Where was the base dyno run done? At MTI as well? The first dyno run may have been very generous.

Anyways, I think the biggest thing hurting you is that you don't have long tube headers. You will never get the full potential of a cam if you can't get that extra air out. I would always recommend to someone that they get headers first before they do a cam swap and/or heads.
Yes base was done at MTI as well. All of my Dyno tunes have been done by them.

I understand the flow equation with headers but the reason I went with this cam was that results were showing great gains w/out headers. I was not planning on getting headers. Oh well! Lesson learned I suppose.

I had them work up a quote for a header install and I think I might just go with a more aggressive cam too. Well see!!!!! I hate paying twice for a cam install. I tossed $1k away already.

I am really pushing for 400RWHP and was hoping that the setup I have would net around 370-375.

Thx for the feedback!
 

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I wouldn't worry to much about what the dyno says. There is so many variables on each pass. I thought the same thing when I had a Lunati cam installed. Take it to the track an see what the bottom line is. Unless you are going to post your dyno numbers on the back hatch than try not to be to discouraged, although I feel your pain. Although my dyno numbers aren't great, I can still get into the 12's on not so great air and the stock stall.
 

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the air in houstink sucks, especially with this heat. I bet you would be around 400 come october. Just out of curiosity.....what were the IAT's on your dyno run?
 

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your answer awaits you.....

find out all the weather details here for both days....then compare the DA from the first run to second.....the elevated DA will kill alot of performance

http://www.wunderground.com/

then enter the weather info here....just about all of youston is 60' above sea level so use that number for your DA calculation on this link

http://www.modulardepot.com/density.php

then after you have adjusted for the DA keep this in mind as well.....the stock tune has heat soak retard that begins at 84 degrees IAT.....if the MAF was reading 125+ to 140+ which i would bet it was that means you lost a mountain of timing on the pull....have jayson research exactly where the IAT's fell on the heat soak retard table and give you a calculation on the amount of timing the truck was pulling out of the tune during the pull.....

don't sweat it you have the absolute best mid range cam on EARTH PERIOD....line up with those trucks side by side and see where they fall.....their is a 2-3 truck her in DFW that stays near me and i have over spent that truck by maybe $6000....BUT i got more coming for him....my cam needs more stall ALOT MORE stall and a new converter is being built for it right now.....
 

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dynoing in hot weather is horrible... like others have stated already get it to the track and run it, i bet you'll be impressed.. i have heard nothing but praise from more than a few people in a couple different LS2's and have SEEN on the dyno tremendous gains (but the heat will kill it, especially when the coolant gets up past 190, you'll see the temps raise and the numbers drop like a stone.. we have seen dyno numbers swing as much as 15RWHP form coolant temps in the 170's as opposed to later pulls when the temps were in the low 200's-210...
 

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Anyways, I think the biggest thing hurting you is that you don't have long tube headers. You will never get the full potential of a cam if you can't get that extra air out. I would always recommend to someone that they get headers first before they do a cam swap and/or heads.

Not so much with the GT2-3. Its a very, very good cam for usage with stock manifolds....and another mod that sits on top of the engine. I too have the GT2-3, but I installed it mainly for the purpose of that next mod - still, you should have gotten about 15-20hp (peak) out of that cam, with the gains realistically starting above ~4k rpm.

Incidentally ADM pulled ~390/390 from his own truck with the GT2-3 and his other bolt-on mods (fans, intake, UD). While I also agree that MTI is a very reputable shop, there's more untapped somewhere in TXSS's truck.....
 

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I had the GT2-3 cam in my 02 Firehawk and it picked up about 60 rwhp with crappy ARE heads over my stock LS1 with the stock tune. Something doesn't seem right to have such low gains.

The only thing I can think is that the GT2-3 might not be that much bigger than the LS2 cam (can't find the specs anywhere). You might need ported heads in order to take advantage of the increased lift you get from the cam.

-Geoff
 

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dynoing in hot weather is horrible... like others have stated already get it to the track and run it, i bet you'll be impressed.. i have heard nothing but praise from more than a few people in a couple different LS2's and have SEEN on the dyno tremendous gains (but the heat will kill it, especially when the coolant gets up past 190, you'll see the temps raise and the numbers drop like a stone.. we have seen dyno numbers swing as much as 15RWHP form coolant temps in the 170's as opposed to later pulls when the temps were in the low 200's-210...
If you're talking about mine, it was closer to 20 that we picked up by letting it cool by 20 deg. I'm sure you've seen that on many but I was amazed at how much of a difference it made seeing it first hand.
 

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Discussion Starter #14 (Edited)
Im sure weather does play a role. The first tune was in 65 degrees (fall) and the second was in 90 degrees (summer).

I cant post the sheet right now but it has some weather data on it:
Pre Cam Dyno - 65 degrees - 30.48-0.15 in. Hg.

Post Cam Dyno - 90.6 degrees - 30.17-0.82 in Hg.

Do you really think that may be the biggest culprit here? Can that difference really steal 15-20HP? We let it cool in front of the floor fan for 30 minutes before the second and third runs so it was much cooler than run 1. We gained about 4HP from that strategy.

Well, theres not much I can do about it now other than gripe and move on or install a larger cam and other stuff.

I am testing a "stage 2" intake thats a prototype from another vendor next week so I get to go back and do it all over again. I dont suspect any huge gains but the way its been going, I could lose some or be very pleased at the end of the day. We shall see!!!!

Thanks for all the feedback guys and I will take it to the track soon too. I think my best precam was 13.4X or 13.5X. Cant find the slip but again, we shall see.....
 

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The dyno (if dynojet) should do a pretty good job to correct for weather.

Post the graph. I think this has been covered already but you need to judge how it feels to you.

I did a GTO on the dyno a couple weeks ago that showed a measley 11 rwhp peak hp but picked up a solid .5 in the 1/8th.. so theres more than just peak numbers on the dyno
 

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Discussion Starter #18
Not trying to get off subject here but how do you guys think this cam compares to the one offered by Speed Inc.?
Here are the specs on the GT2-3:
207/220 571/.578 w 1.7 rocker 118.5 CL


Curious to those that installed the GT2-3 with good gains (15-20rwhp), what valvetrain upgrades did you go with? The company that did the install only replaced springs and went with a single spring setup. Not sure which ones. Ill have to find the box but I wonder if this maybe left a little on the table too? I have some valvetrain noise at idle.
 

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Here are the specs on the GT2-3:
207/220 571/.578 w 1.7 rocker 118.5 CL


Curious to those that installed the GT2-3 with good gains (15-20rwhp), what valvetrain upgrades did you go with? The company that did the install only replaced springs and went with a single spring setup. Not sure which ones. Ill have to find the box but I wonder if this maybe left a little on the table too? I have some valvetrain noise at idle.
To maintain proper valvetrain geometry they should have used 7.425" pushrods with the GT2-3 (given that you have stock unmilled heads / stock head-gasket). As a result of using stock 7.400" PRs, you have less preload on the lifters which typically will contribute to a little more clatter (as will upgraded springs anyways). You're still within an acceptable range of lifter preload, but its definitely on the light side. BTW, this typically doesn't affect the power output but the dyno curve should be an indicator of that (ie, what's happening in the upper RPMs).

I'd wager they used Comp 918s, which given the recent quality-issues with the 918s I would suggest that you check the lot # and get in touch with Comp to see if your batch is also one of the affected. In a nutshell, Comp switched suppliers on the 918s (from PAC to ???...my guess is an offshore supplier) and have suffered some significant quality problems as a result. That is, springs *breaking*.

I used PSI LS1511 beehive springs. The best beehive out on the market, IMHO.

SomeGeoff - stock cam is the same as the '01 LS6 - 204/211 .525", so the gains to the GT2-3 aren't going to be nearly as great as from a typical LS1 cam...but still 15-20 gains should be the norm.
 

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Discussion Starter #20
To maintain proper valvetrain geometry they should have used 7.425" pushrods with the GT2-3 (given that you have stock unmilled heads / stock head-gasket).

I'd wager they used Comp 918s,
He left the stock pushrods in. Said upgrading them was a waste.
He did tell me that I need to expect extra valve chatter after the install. Is that normal!? I played with motors and valvetrain replacement years ago and dont remember that being an issue with properly matched components.

They are Comp 918's and I will contact them today to see if there are any potential issues. Thanks for the heads up on that one!

I appreciate your feedback!
 
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