Dynamometer Results & Comparisons - 1000 rpm's MISSING!
04-04-2006, 10:28 PM
I am currently running the TR230 cam with stage 2 863 heads and I just had the car dyno tuned and the power band falls off at 5600 rpm's! The car puts out 382rwhp and 387tq at 5600! The cam's potential is suppose to be to 6800 rpms! How is this possible? Anyone have any ideas or know the answer please let me know!!!!
04-05-2006, 12:07 AM
If its peaking early then 2 possibilities.
Cam is either advanced or retarded too much (cant remember which one lowers the powerband). I think its advanced too much. Could be wrong though.
Valvesprings are taking a shit. Valve float. Is the graph very choppy after 5600? If so, then you should get new valvesprings
Billy the Great
04-05-2006, 12:12 AM
Quinn is that you????
04-05-2006, 12:43 AM
if you could post a graph that would help a lot.
04-05-2006, 06:17 AM
I would guess valve float I had the same thing happening. Motor would just nose over at 5700 5800. Sucked at the track.
04-05-2006, 07:12 AM
same thing here,total washout at 5800.pulls strong untill then.its like hitting a brick wall.
04-05-2006, 08:07 AM
Are you running a stick or an automatic? Locked or unlocked?
04-05-2006, 08:25 AM
What kind of valve springs do you have? Is your lift at or close to .650?
If so sounds like you need some good 921 comp dual valve springs. Good for lifts up to .650 LG got me 460+ rwhp with heads/cam and all the usual bolt ons. The G5X3 cam with a .600 lift and .608 exhaust made power all the way to the 6800 rev limiter.
With Comp R lifters and the titanium seats and removing the rev limit, the engine should pull all the way to 7750 rpms. But for engine longevity thank god for limiter.
04-05-2006, 08:35 AM
There are all kind of possibilities, I wouldn't discount
some of the simple things like running out of fuel (like
crusty fuel filter, weak pump wiring, etc.). Hooking up
the wideband (better yet, some real logging of engine
goings-on) is better than speculation.
04-05-2006, 08:46 AM
Jimmy makes a good point, what size injectors? Did you run out of fuel? If you run super lean, say goodbye to the motor.
04-05-2006, 09:35 AM
Im thinking valve float. I saw it happen many times.
04-05-2006, 10:12 AM
What springs are you using?
04-05-2006, 11:10 AM
whtltngzls1,lets see if we are on the same page,does your torque mirror your rwhp?in other words does your peak hp and torque rise at just about the same rpm?my torque starts comming around at about 5400 rpm.
04-05-2006, 11:09 PM
Well I am currently running the comp 918 springs because its only 575 lift! I know the valves are not floating but I did however use the LS7 timing chain on the stock gears and there is a lot of play in the chain soo I think that might be the problem! The graph is too big to put on the site but the hp curve is very nice and the torque curve is nice! No jagged lines all smooth! I dunno I checked the timing marks and their lined up soo I am stuck! I think I am just gonna put a stock chain on and see what happends
04-05-2006, 11:15 PM
The injectors are stock and the fuel pump is stock and the air fuel ratio is great so I don't think that is the problem.
04-09-2006, 07:03 AM
For the graph.
Do you have Office 2003? It has a program, Office picture manager, that allows you to resize pictures for posting. Open the graph in that prog and go to picture in the menu bar and pick resize. Choose web small or large, it will show the picture size in kb on the left as you need to be under 100kb. Or zip the picture using winzip and post the zip as an attachment.
04-09-2006, 07:42 AM
Do you have a stick or an automatic with a high stall converter? The answer to that question will mean everything.
Billy the Great
04-09-2006, 05:09 PM
car is stick with a luk clutch and a stock 3.23 gear
does anyone know of someone running the ls7 chain on ls1 sprockets? are they interchangeable? cuz that would definatelt explain the shift in power band
Quinn, how is the idle and street characteristics of that cam, like i told you. Whats the oil pressure at now? Heard you neighbors "love" the exhaust setup :)
04-10-2006, 12:27 PM
ls7 chain is same as the ls2 which plenty of people use w/o issue . you really need to log a run and see whats goin on. could be something real simple. or even an intake restriction holding you up.
04-10-2006, 12:39 PM
6 speed with 3.23???
Get that graph up.
If the cam is advanced it would make more down low than normal too
04-10-2006, 12:53 PM
i found mine!
Billy the Great
04-10-2006, 12:55 PM
whats was it?
04-10-2006, 01:01 PM
im gonna say fuel filter, i NEVER hear of anybody on this board talking about fuel filters being swapped, its really important to do this. my cousins 91 firebird used to fall on its face at 4100 rpms, changed the fuel filter, pulled to 5200 and chirped second...
04-10-2006, 01:01 PM
here it is
04-10-2006, 01:33 PM
We've discussed it for years, unfortunately the search only goes back to 1-1-06.
But good call.
04-11-2006, 11:10 PM
The idle is faster and like before I had the car tuned it sounded great like good and loapy now its like at 950rpm's and you can not really hear the loap! Yea I found out the ls7 and ls2 chain as well as the ls1 chain their all the same part number and the chain is heavy duty so I am thinking I might have to get the new gears! I swapped out the old spark plugs for new TR6 plus and ran the car on 110 oct it idled a little better! I also put a scan tool on the car and looked at the data and misfire data and there is no history of an misfires or any history of the knock sensors sensing anything so its not pinging! Thunder is telling me to degree the cam now but you can't with hydraulic lifters you need solid lifters soo I am really stuck!
04-11-2006, 11:27 PM
Ha I figured it out ok here is the graph of the Pull! Tell some more ideas please cause I'm loosin sleep over this haha!!
04-11-2006, 11:33 PM
Here is the graph!!!