403 tfs235 low dyno numbers
403 tfs235 low dyno numbers I've had my combo together for a little over a month now and have finally gotten it on the dyno and to my suprise was fairly low, I think.
Specs:
403 Iron Block, 11.7:1 Compression
Scat 4.00" Crank
Eagle 6.125 H-Beams w/ ARP2000 Bolts
Wiseco -3cc Nitrous Pistons with Hellfire Rings
TEA ported Trickflow 235 Heads, flowed 347cfm@.600"
25x/25x Vengeance Custom Cam
LPE Ported FAST90/Nick Williams 90mm TB
ARH 1-7/8 Longtubes & ORY open at the end
made 489rwhp/441rwtq SAE numbers
this setup is in a nearly full weight 00 z28 mated to a built t56 and a moser 9". The day before I had just taken it to the track and clipped off a 1.58 60ft 6.89@102 10.74@127 timeslip. It had trapped as high as 129.6mph on a previous trip to the track. I'm pretty sure these numbers are off!
EDIT: Im pretty sure I had some bad gas on the dyno because the car is currently running rough with this tank of fuel. I'll get back with some results and some better gas!
Specs:
403 Iron Block, 11.7:1 Compression
Scat 4.00" Crank
Eagle 6.125 H-Beams w/ ARP2000 Bolts
Wiseco -3cc Nitrous Pistons with Hellfire Rings
TEA ported Trickflow 235 Heads, flowed 347cfm@.600"
25x/25x Vengeance Custom Cam
LPE Ported FAST90/Nick Williams 90mm TB
ARH 1-7/8 Longtubes & ORY open at the end
made 489rwhp/441rwtq SAE numbers
this setup is in a nearly full weight 00 z28 mated to a built t56 and a moser 9". The day before I had just taken it to the track and clipped off a 1.58 60ft 6.89@102 10.74@127 timeslip. It had trapped as high as 129.6mph on a previous trip to the track. I'm pretty sure these numbers are off!
EDIT: Im pretty sure I had some bad gas on the dyno because the car is currently running rough with this tank of fuel. I'll get back with some results and some better gas!
Last edited by LSxPwrDZ; May 19, 2010 at 11:14 PM.
The dyno is known to read low but to me the torque is off by 40-60ftlbs and the power is also down 50-60hp I would think. It was a dynojet 224 on the SAE settings. Peak power was at 6000rpm which really suprised me for a cam this size! The MAF is maxxed out both ways hitting 12000hz and 512g/sec also! Running 60lb siemens with the correct injector data.
First run only pulled 469/43x and I ended up throwing tons of timing and leaning the a/f mixture out to pull the 20hp out of it. Final tuneup was running .91-.92 lambda or 13.4afr and it was seeing 28* at peak torque and ramping up to 31* by redline. That is what it liked in order to make the power. First pull was somewhat rich at .83 lambda or 12.1afr and was running 24.5* at peak torque. So basically it's not in the tune, it is in the setup or the dyno.
First run only pulled 469/43x and I ended up throwing tons of timing and leaning the a/f mixture out to pull the 20hp out of it. Final tuneup was running .91-.92 lambda or 13.4afr and it was seeing 28* at peak torque and ramping up to 31* by redline. That is what it liked in order to make the power. First pull was somewhat rich at .83 lambda or 12.1afr and was running 24.5* at peak torque. So basically it's not in the tune, it is in the setup or the dyno.
I'm not really worried about the dyno numbers but I feel that the setup should make more power than it does and if I can make the car run these times with this power then what can I make it do if it makes the power it's supposed to. This is the main reason for my post, I'm just needing an outside eye that may see something I'm overlooking. This particular dyno has had a stock bottom LS2 with these heads and cam and it laid down 480hp. Surely a higher compression stroker would make more than 9hp more?
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I'm not really worried about the dyno numbers but I feel that the setup should make more power than it does and if I can make the car run these times with this power then what can I make it do if it makes the power it's supposed to. This is the main reason for my post, I'm just needing an outside eye that may see something I'm overlooking. This particular dyno has had a stock bottom LS2 with these heads and cam and it laid down 480hp. Surely a higher compression stroker would make more than 9hp more?
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Verdad Gallardo Do you guys think bad gas could be a problem here? Cause I filled up right before the dyno run and had my tune nailed at the track the night before but was running 8-10% rich after I filled up. I've got the datalogs from hptuners and a dual channel wideband that shows this difference also! Has anyone experienced bad tanks of gas causing a rich a/f mixture?
It was speced for this setup, which was all out drag racing with a good size hit of nitrous in mind. I wanted a powerband up to 7000rpm to really generate some HP but the peak power on this setup was suprisingly at 6000rpm. It didn't really fall off much all the way to 7200, it just peaked at 6000.
It's running a oem gm 85mm maf and an slp lid. Out of curiousity we put the car in sd and pulled everything off and ran it open throttle body and it did pick up like 2hp. The biggest thing I noticed is my map was toggling 98-99 kpa with no lid or maf with open throttle body, with the lid and maf on it was pulling 94-96kpa!
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I wouldn't worry about the numbers either. Sounds like a very STINGY dyno. You have a very similar setup to mine but more compression, bigger cam, and a bigger set of TFS heads. My cam is only 239/243 .623/.623 113+3. You said your power peaks at 6000 and holds pretty much to 7200? That should rule out using the wrong length PR's. Wrong pr's would be indicated by a huge drop off in power if I'm not wrong. Any valve float?
Could you post a graph ?
Could you post a graph ?
IMO the cam is too big and def not a n2o friendly cam.I;m sure the intake runner length is hurting as well since it is not matched to the camshaft.My suggestion would be to go about 10 deg smaller on the intake lobe,shorten the runners in the intake.A 6 speed car with this engine should easily go 131+
being full weight and running those times i'd say it is putting out decent power. try another dyno that has a dynojet also and see what that gets you. with only a 4* split i might be cautious on how much i would spray. alot of the BIG shot cams have atleast 8* split or more. just my uneducated $.02
Just some more info on the track times. The calculated DA on the runs was around 2000'. I also agree on this setup being well capable of trapping 131+. More info on what has been removed from the car from stock, front and rear impact bars, front sway bar, AC, ABS and passenger airbag have been deleted. Weight added from stock would be an iron block vs aluminum and a moser 9" vs 10 bolt. I've not been able to get the car on scales to see exactly what it weighs.
I've contemplated swapping the intake to a Vic jr and accufab 4150 TB with a nice plate kit under the accufab. Then if needed swap cams to taylor to that manifold and a 300-350 hit in mind.
I've contemplated swapping the intake to a Vic jr and accufab 4150 TB with a nice plate kit under the accufab. Then if needed swap cams to taylor to that manifold and a 300-350 hit in mind.
It seems like there are very few f-body n/a strokers running faster than a 132 mph trap in a 6 speed or automatic not matter what the claimed rwhp is. Most run in the 128-132 range. There are a couple that run 136-138 but it seems like they touched on something magical. Obviously weight is a huge factor.
I have a LS7 427 w/ TFS 235s and one good night (temp was low to mid 50s and fairly dry) I ran 132.51 - 132.76 all night. I haven't run the car enough to get all the bugs out but have not duplicated that feat. Most are in the 131 mph range. My race weight is 3600-3650 and I'm running stock front tires.
Seems to me that reaching over 550 rwhp n/a is more difficult than most seem to realize.
So to me 127 isn't too bad but there is probably some room for improvement.
I have a LS7 427 w/ TFS 235s and one good night (temp was low to mid 50s and fairly dry) I ran 132.51 - 132.76 all night. I haven't run the car enough to get all the bugs out but have not duplicated that feat. Most are in the 131 mph range. My race weight is 3600-3650 and I'm running stock front tires.
Seems to me that reaching over 550 rwhp n/a is more difficult than most seem to realize.
So to me 127 isn't too bad but there is probably some room for improvement.