ok i threw this together with parts i would like to buy for my 305 (torquer s/r's and a nice cam, assuming small tube headers with cutout valve. also a 670cfm TBI)

would i really be making close to 400hp !?

 

400 HP is really stretching it. Youd probably get closer to 275 horsepower, maybe more. Alot of your power is going to depend on what the tune of the ecm is. If you get it tuned in right, you could probably make some decent power. Dont tune it, and itll be a pig.

 

well i will be ordering a custome chip from tbichips.com that will suite my needs.

 

That's utterly ludicrous.

You've put the wrong parts selections in there. For example,a "high-performance street roller" would have lift around .600" and a .050" duration less than 30° different from its "advertised" duration. On the other hand, a cam such as you have there, will have about 60° - 70° difference between its "seat timing" duration and its .050" duration. So you've forced the program to overestimate your cam duration by 30 - 40°..... which could be a significant source of error. A typical hydraulic roller cam should be entered as a flat tappet.

That program is also widely known to overestimate the effects of headers.

Change the exhaust to manifolds, and make that cam change; and see what you get. That answer will be considerably closer; maybe within 20 HP or so, instead of being 150 HP off like it is now.

 

i dropped the cylinder heads from ported/large valves to stock and changed the cam to flat-tappet and it came to roughly 310hp, when i changed from open headers to HO manifold, it only dropped about 10hp

 

Still seems rather high to me; but you can see how easy it is to send that program off into the outer ozone layer with overly aggressive or optimistic assumptions. Always take it with a grain of salt. I don't think I've ever seen it estimate to the low side of reality yet.

 

The BIG thing with Desktop Dyno is this...


DO NOT USE the ROLLER cam selection, EVEN if the cam you're using IS a roller. It bumpes the figures WAY up when you do this.

I haven't got into, "why" it does it, but it does.


For comparsion...

The last three engines I've put together ( One was a pre built short block, sue me :P ) THAT were dyno'd ( all flywheel numbers ) were compared with Desktop Dyno....

Desktop dyno was pretty friggin' close to be what it is...

On the average it was 20 HP / 15 ft/lbs HIGHER on the REAL peak numbers....The difference was lower or same across the board.


YMMV

 

The one from performance trends(?) is a better program then D-D. Seems to give more realistic results.

 

Ive always been a bit leery of the mail order stuff. Its the equivelent of one size fits all underwear. Youll get the best performnace by doing the tune yourself.

 

sometimes that's not always an option. Brian from TBI chips tuned me a custom PROM, and assuming my car will ever start, he assured me it would run very smoothly. He's been doing this for years, and while he may not have access to your car physically, he knows what he's doing. But yes, I'd much rather tune my own car, but I can't afford the equipment and I don't have the time to do it.

 

Hes definatly one of the better ones out there. One thing is though, its like taking a holley carb and mailing it out to someone and asking them to set it up for you, but not telling them anything about the car. Sure, he may have data logs and such but those are only about 30 % of the story. I was PO'ed about having to drop 200+ on the stuff to do it but in the end Iw as very happy with the results. Not only that but getting into ecm tuning opens up doors that I never even knew where there. Not tuning is like buying a holley 650 and vac. advance distributer, bolting it on, and never touching it again after you put it on. A carb guy would say thats rediculus, you have to be able to tune it. Same thing with the ecm. Its almost a must if your running a modified setup.

 

You'll only get close to the power shown in DDyno
*if you built the motor the way you modeled it.*
You choose a head that flows 242cfm @25"
Thats about 250cfm@28" (Standardized)
Stock out of the box Torquer S/R 305 heads are not even close to this. (they flow about 205cfm@28") You would be hard pressed to achieve this flow after max porting these heads. And then only if you were real good at it.
You also choose a roller cam (very radical rate of lift mechanical solid race roller) not your typical hyd roller.
The cam you choose would have a .050" duration of 244 degrees.
If you meant to model a set of stock out of the box S/R heads you would choose "low performance stock ports and valves" this menu choice best models out of the box S/r heads. (in out of the box form they only flow a little better than a stock head.)

If you meant to actually choose a typical hi perf hyd street roller you would select " hyd" and "solid" as the
best model would fall some where in between these choices.
The "roller" menu selection really is intended for a radical
race cam lobe. even many real roller cams are not as intense as this selection.

With out of the box heads and a hyd roller of the duration and lift you choose you'd realisticly see about
325gross Bhp according to DD2000.

 

i dont think u read my own reply in this post to what i changed. lol

*scroll up*