Josh

iTrader: (9)

Hey Guys,

I really need some help on this one. I had my car dynoed today and only made 383 RWHP and 361 RWTQ with the T-ReX. I was hoping for (and expecting) at least 20 RWHP more.

My mods are listed in my sig. As you can see on the attached sheet, the AF ratio was darn near perfect and I was getting no KR with 30* of timing. The cam is lined up perfectly (obviously) and I've never had the heads off of the car, so it shouldn't be a rocker-related issue (unless the owner before me messed with them, but I doubt that's the case).

I installed a March UD pulley just before heading to the dyno, but I see no reason to believe that is to blame for the low numbers as the belt lines up just fine. I didn't have the AC belt on the car, but I doubt that would have any effect on the power.

My first two thoughts are that my clutch is slipping horribly and/or my Y-Pipe is crimped (I have dragged it on speedbumps several times, but there appears to be no damage looking underneath the car).

My friend dynoed before me and made 398 RWHP and 415 RWTQ with Patriot Stage III LS6 heads, a 230/236 cam, and all the bolt-ons through an A4 with 3.73s and a Yank SS4000.

Anyone have any ideas? I dynoed the car on a different dyno when it had only a lid, LM, and Hooker LTs and it made 320 RWHP and 330 RWTQ.

On the computer screen at the dyno, the graph was virtually flat at 6500, so I highly doubt I would've seen more than 400 RWHP at 7000. Ignore the first run, it's virtually pointless as I stopped at 5500 RPM at the request of the operator.

Thanks in advance,
Josh

McRat

For one, you didn't rev it high enough on the dyno. It was still climbing.

kumar75150

its still down on power but i would have revved that thing to 7k

Josh

iTrader: (9)

It picked up maybe 10 RWHP from 5500 to 6000 RPM, so even if I had taken it to 7000, I doubt I would've seen 400 RWHP.

Josh

AK's WS6

Sorry but what are the specs on that cam again?? Is it possible that it is a little big for stock heads??

Tech

iTrader: (1)

Keep your foot in it longer.

WildBills Toyota

iTrader: (1)

ya, need some more rpm bro. That cam is made to go high like 6900-7000k

jruss

as shown here bigger isnt always better

soundengineer

iTrader: (16)

A4??? get a little less from an auto....
stick probably would have been 400...which I think I have been seeing as the average.... but with heads you should see 420+ easy if you spin to 7k where the t-rex really makes power...its really not a stock internals cam...you gotta spin that boy high...

and I think really 440+ is attainable with good heads..
that cam is too big for stock heads...the stock heads will not support enough air to get real power out of it...

Pacific Muscle Cars

Take the car to the track and see how it performs. I wouldn't get too caught up on peak #'s. Your torque curve is very strong, and very flat - which is shocking for a cam of that size. Your power doesn't appear nearly as "peaky" as other T-Rex dynos I've seen.

Do you have the dyno sheet for the other session you mentioned (lid, exhaust, LT's)? I am interested in seeing the curve, because those peak #'s also seem low. My '02 Z28 with the same mods (Hooker LT's, ORP, catback, lid) put down 350rwhp/360rwtq with a very flat torque curve.

Josh

iTrader: (9)

Thanks for the responses, guys.

As far as revving it higher, yeah, I probably would've picked up 5-10 more RWHP, but that's still way lower than I was expecting. Take a look at SMOKIN01TA's graph: https://ls1tech.com/forums/showthrea...=166035&page=1. The power really stops climbing at 6500 and holds steady. Jason's car peaked around 6500 RPM as well (http://www.thunderracing.com/dynogra...n=read&pgid=60). DanZ28's car didn't do much after 6500 RPM either (https://ls1tech.com/forums/dynamometer-results-comparisons/167792-trex-dyno-numbers.html).

I really don't think the cam is the problem, the T-ReX has proven it can make big numbers on stock heads. My mods are very similar to HO99SS's, and he made 439/375 through 4.10s (https://ls1tech.com/forums/showthread.php?t=162142).

soundengineer: The car is an M6.

I've attached the graph of my car with just a lid, Loudmouth and LTs.

Thanks Again,
Josh

GPowrie

Looking at that dyno graph I almost wonder if some how they mixed up the cam. It looks like you are making peak torque at 3300 rpm, which I would think is very low in the powerband for that cam. A lot smaller cam could make peak torque that low and would explain the low hp number.

SilverGhost

iTrader: (53)

i say compare what you gained man.

if all you did was the cam and a pulley and you gained 63 rear wheel and have a good looking graph you should be happy. that's what its really about, what you gained before and after not comparing to other cars with similar mods. every car is different.

but take it to the track and see what the MPH is, then you'll know

Pro Stock John

iTrader: (34)

How was the cam degreed, describe it to us.

Josh

iTrader: (9)

Dot-to-dot using the stock chain and gears.

LOL, one might think by looking at the graph, but I have the cam card with the appropriate specs. I agree, though, the torque curve is almost too flat for this cam.

Josh

Mike K.

If you take off your cats that could be another 10 hp maybe. Try some cutouts as well. Also did those other guys use a shortbelt? Do you have a ported TB? All of the little stuff adds up especially on the dyno. Also you said you have thunder pushrods are you sure your preload is right? There is more power left in that bad boy, you'll find it.

Josh

iTrader: (9)

No, no one ran with a short belt. If I were to gain 10 from removing the cats and another 10 from a ported TB, I'd still only be at 400 RWHP. Not bad for a cam only car, but with this particular cam, I would hope to be easily over 400.

No one thinks it could be a slipping clutch?

Josh

jerflash

what lifters and springs did you use with theis cam?

Brian2001SS

iTrader: (1)

Josh, it could be the Dyno. Come down to Atlanta and run it at Dyno Lab and compare results. You could be supprised at the difference.

ta12sec

iTrader: (3)

go drve it put it in 3rd at about 30 and put it on the wood, does the tach jump up and the car not move? How many miles are on it, did you have the car tuned? what kid of gas were you running. how olds your fuel filter, plugs, wires air filter got a plastic bag in it?