FST Dyno Sheets request

[MrGas]

Can anyone provide me with a FST legal Dyno sheet to see? With Or without Restrictor plate. I am working on my engine combo and would like to see some Data from the experts. Thanks Greg

[rgu]

chassis dyno?

[MrGas]

chassis dyno?

Either one is fine . Chassis or crankshaft. Its all Informative. Thanks

[veefan]

These are the dyno sheets of a fresh built FST engine, hope it helps. This is a fully set up race ready engine with the restrictor plate, new case, heads, cam, crank, all parts fully balanced and set up.

[MrGas]

VEEFAN thanks for the Dyno sheets. Pretty amazing to get 84 whp from a 1585 cc pump gas single 34mm carbed Engine.

[Diamond Level Motorsports]

I think those numbers are engine HP, not wheel HP

Otherwise my engine is way down on power.....

[rgu]

Definitely engine. I've heard peak figures for chassis dynos around 72-75 but too many variables affect chassis dynos even with crude (no computers) FST engines. This curve is typical though--peak power 54=5600 RPM and nice and flat

[MrGas]

Yeah, Flywheel HP make more sense!
I have built many 1835 single weber engines that can barely achive 100hp on flywheel dyno.
Nice Flat curve and lots o torque looks good!

[enrikerace]

These are the dyno sheets of a fresh built FST engine, hope it helps. This is a fully set up race ready engine with the restrictor plate, new case, heads, cam, crank, all parts fully balanced and set up.

Can you repost the image please??

[Jnovak]

Can you repost the image please??

Yes

[enrikerace]

yes

please

[sracing]

Thread is aging, but:

We had 2 engine dynos and a chassis dyno. The engine dyno is great for after the build, for tuning and bragging rights.. But a very big time waster after that. On our three rental cars we put them on the chassis dyno after each race weekend. We wanted to see the trend and what HP went to the wheels. The drive train represents 10% of your HP. You could check all gears and easily tune for air-fuel mixtures etc. and see immediate results. We could do all 3 cars in under an hour. I would never part with the engine dyno but 85hp there doesn't mean much if you have only 60 at the wheels. Very interesting to see what 90W verses 140W gear oil means. Or wheel weight or transmission losses. Also on the chassis dyno you are typically doing "inertial" HP, verses normal brake HP (at some defined acceleration rate. Usually 300 RPM / sec) on the engine dyno. On the track INERTIAL HP is what counts. IE. How fast can I accelerate from 70 to 100 in 4th gear? If I can accelerate from 70 to 100 faster than you, I don't care if you have 5 more HP at the flywheel.

If you are in to comparisons, the chassis dyno is far more valuable. Our engine dyno had full acceleration rate control, but the vast majority of VW type dynos do not. Without rate control 20% of the real HP is the dyno operator. With rate control you simply go to WOT and the dyno controls the run. Similarly to the chassis dyno.

Just some thoughts...

[Daryl DeArman]

On the track INERTIAL HP is what counts. IE. How fast can I accelerate from 70 to 100 in 4th gear? If I can accelerate from 70 to 100 faster than you, I don't care if you have 5 more HP at the flywheel.

Some valid points made in your post. However, on the track ALL THE VARIABLES are what count. As long as I'm in front of you when we pass the finish line , I don't care if you can accelerate from 70 to 100 in 4th gear 1 second faster than I can though if you couldn't do so, my job would be that much easier.

Same thing with dyno HP. If I have +5HP across the curve it makes the rest of my job easier.

[sracing]

Well, I certainly agree that if you have 5 more HP than someone else it makes your job easier. Assuming it is AT the rear wheels

If it IS at the rear wheels you CAN accelerate from x to y faster than the guy who is 5HP down.

Yep, good to start with lots of HP at the flywheel. It's also good to start with good flow numbers on the induction system. However there is lots of stuff after that. The chassis WHP numbers (with curve) is the final decision of what car will accelerate from x to y faster.

Some valid points made in your post. However, on the track ALL THE VARIABLES are what count. As long as I'm in front of you when we pass the finish line , I don't care if you can accelerate from 70 to 100 in 4th gear 1 second faster than I can though if you couldn't do so, my job would be that much easier.

Same thing with dyno HP. If I have +5HP across the curve it makes the rest of my job easier.

[Daryl DeArman]

However there is lots of stuff after that. The chassis WHP numbers (with curve) is the final decision of what car will accelerate from x to y faster.

Racer X has a crap engine and very efficient drivetrain. Racer Y has a bullet engine and crap drivetrain. They both end up with the same curves on the WHP but neither knows where to concentrate their efforts. They both accelerate at the same rate only if they have the same drag and mass.

Engine dyno to optimize engine. Chassis dyno to optimize remainder of drivetrain. Stopwatch and results sheet to optimize everything else.


Any FST dyno sheets found?

[sracing]

Geesh, Daryl. You are preaching to the choir. Of course you want to start with a good engine.

You are now throwing in driver ability drag and mass. Neither dyno helps with that. (Although, I can alter the effective mass of the vehicle on the chassis dyno. )

In a few minutes or <~$100 (if you don't have a chassis dyno,) I can continue to monitor the performance of the over all drivetrain. Not many people would want to engine dyno very often.

I think dyno sheets have already been posted but I found an old 3rd gear warmup run from 1992. After the engine reaches full temps another couple HP peak is found. Also a 4th gear run will show the same curve IF the trans/diff is OK. That's another nice thing about the chassis dyno. I can check any gears performance. You can't do that on engine dyno.
Of course, I can change the graph to show an X scale of RPM also. On the chassis dyno I can put in the gear ratios and the program will compute the best HP "under the curve". Thus showing the exact shift points for maximum use of HP. Obviously on a road course the driver has to make some determination of shifting for corners, drafting, etc. etc.
We had dozens of drag car folks who brought their cars in after almost every event. Removing the engine for a engine dyno run was pointless if the results were good. Also, it was great to see the actual HP changes based upon wheel mass, trans temps etc. Beating a dead horse here, but after the drivetrain reaches temperature I can do 4 or 5 runs and the curves laid on top of each other are identical. Try that with a typical FV engine dyno.. Let me know if you have questions on the dyno sheet. Great discussion.

Racer X has a crap engine and very efficient drivetrain. Racer Y has a bullet engine and crap drivetrain. They both end up with the same curves on the WHP but neither knows where to concentrate their efforts. They both accelerate at the same rate only if they have the same drag and mass.

Engine dyno to optimize engine. Chassis dyno to optimize remainder of drivetrain. Stopwatch and results sheet to optimize everything else.


Any FST dyno sheets found?