ok, since the latest thread on dynos and raif being dynoed. I wanted to try the desktop dyno 2000 vs the reality dyno. Since raif is the only one well documented on the mods and has had a true dyno. I plugged them numbers in. Now its at 18deg of timing, and program will only let me go up to 15deg.

Reality dyno is:
Max Power = 141.3 @ rear wheels (+20%) = 169.56hp @ the fly wheel
Max Torque = 221.3 @ rear wheels (+20%) = 265.56ft-lbs @ the fly wheel

Computer dyno is:
208hp@5000 flywheel, which should be 166whp
237tq@4000 flywheel, which should be 189.6wtq

 

dave88, your computer results are:

172hp@4500
232tq@3500

 

so what a 45 degree advance wouldn't work

 

my computer results are:

186hp@5000
238tq@3500

 

correct

 

deans inital 3.5l

207hp@4500
247tq@4000

max useable rpm 7500 even though it really dies off them last 500.

 

87blues proposed engine

283hp@6500
262tq@5000

useable rpm range all to 9500rpm. But hes gonna have to rev it to 3000rpm to take off

 

hey run one for me, TPI 305
this cam 305 5spd / 350 AT 10066049* .415 .430 207 213 117.0 (116/-118)
it is rated at 230hp, 300tq,, oh it had a 45* igntion advance stock advance was too slow.

 

You know that's cam timing, right? It has nothing to do with ignition timing.

 

I cant do 45deg of timing.

Would also need tb flow.

For any dyno test I need:
Block mfg
bore
stroke
cylinder head flow numbers in .05 incraments
compression
tb cfm flow/intake style (carb, mpfi/sfi, etc)
camshaft specs.
Timing, and it will only let me go up to 15deg of timing.

 

Then why does the 3.1 need 10deg of timing to make it accurate with gm specs, when the cam should be at 0?

Why does the 3.4 need 0deg of timing to make it accurate with gm specs. And you can not set ignition timing on a 3.4 sfi

It would then put raifs at 237/239, which is futher off then what she dynoed at.

mine would then be 188/237. Which I dont think it even has the 186/238 it claims it has anyway at 11deg.

 

Because it's only a model that tries to make an approximation of the performance of the engine based on a limited set of parameters. It assumes that timing is optimal and the octane rating of the fuel is sufficient to avoid detonation.

Likewise, it knows nothing about the weight of the valvetrain components and the spring rates, and so doesn't predict the redline accurately.

 

Jay, i just can't buy into that computer dyno stuff even being close to accurate.. It can not ake into account for the featherweight bottom end, the longer rods, the Supersix heads benchflow ported with 1.8 and 1.5 valves, the aluminum roller valve assembly, the lack of waterpump, and the rest of the overall lightness and lack of HP robbing parts on the motor belt system etc. (parts like thealuminum fluidampr balancer)

I will gaurantee a rwhp of 250 with a SC application I paln to go to to keep this car more mildly cammed and compression ratio for smog reasons- I can remove the SC for smogs. Without the SC I am expecting about 225 fwhp or 200 rwhp

PS- I have decide to finally put the headers on the car- They aregoing in as we speak, I am taking a quick break and getting a bite to eat.

 

rftc, you are very correct, it doesnt take into account for any of that EXCEPT the ported heads. You get me flow numbers, I can change it. That was with the current release of supersix heads with "stock" valves.

 

i agree that it won't give you a perfectly accurate rating, and it prolly won't give you a close to accurate rating, but it is fun to play with. it is only a theoretical dyno. not one that actually measures anything from the car(hp or tq) as what rftc said, i am ordering the best cam that they make for the engines, a circle track cam, and just about all of the best parts i can find for the engine. i am planning on running the dry sump water pump set that rftc was talking about, the computer dyno can't take into account for rotating weight or anything else like friction or wear.

 

im running about 12 degrees of timing, i forgot to tell you that, but i have run up to 15 on premium at the drag. sorry dale i forgot to tell you that.