Engine Dyno Myths...

[hawkeye18]

If you already have the ability to make the changes and data log, there's no need for a dyno to find out that information.

Just trying to help him justify his desire to blow money on a dyno, I suppose.

 

[Toolman]

Dyno is free guys.

 

[yamahaSHO]

Thought it was $90.

 

[auto.guru]

$90 to the open public, 3 pulls.

since i built my engine with my teacher whos showing me how to strap my car up to the dyno (for class demonstration), i dont have to pay. Its a free 3 dyno pulls - maybe 4 or 5 depending on time/demonstrative lessons.

 

[auto.guru]

turbocharging a SHO is not worth the effort, but it sure is fun.

If you have a free dyno, and you gain some knowledge for the 10 minutes it takes to swap a different intake on, I say go for it.

hmm, believe it or not i have an old 3.0 intake sitting in the basement together. I could take it apart, and remove the butterfly valves, and then reassemble it. Do a comparative test for intakes WITH and WITHOUT butterfly valves.

and altering the secondary open times you need the tweecer. no thanks, im not rich - come on'... im a college student

 

[zak]

yamahaSHO, you miss the point of the experiment entirely. It is NOT to justify everyone removing their butterflies just to make some addtional secondary peak hp and torque (and giving up everything down low, as others have already determined)*, the point is to identify whether or not the butterflies serve as a cork in the system, and whether or not reengineering the whole surge tank/butterfly/secondary runner region might be worthwhile. Some have actually built HBBs etc., but to my knowledge there has been no definitive dyno testing comparing them to say SHOshop 41 mm bodies, properly done 40 mm bodies etc.

The experiment can be done with relatively little effort, compared to designing and manufacturing the parts needed to reengineer the transition. And it might just point us to an approach to achieving the mythical 300 peak hp NA SHO engine.

auto.guru, are your secondary runners ported in any way? Heads unported yes? You will want to use 2 part epoxy with as long a set time as possible to seal up the shaft openings at the ID (Home Depot has a 24 hr set one), then sand smooth. If I had a spare set of unbored butterflies I would send them to you. Consider other methods such as removable plugs, but try to 1.) make sure whatever you use doesn't get ingested at WOT, and 2.) keep the butterfly wall smooth, no blind holes where the shafts were.



* a dedicated track SHO may wish to reconsider this though

 

[auto.guru]

^ agreed. he makes a very valid point. this test is to see those "what ifs". i havent put the engine together yet so we can do some of these tests. Zak, i could also just send you the butterflies and let you do the work since it seems you know what youre talking about more than i am understanding how do it.

heads are ported and polished a full 2mm on each port intake unported. and i wouldnt put different butterflies, but remove them completely just to see if they are a cork. As far as sealing the hole..... i dont think it will skew the results a HUGE amount... and i dont feel like putting 2 hours of work into something just for a test atm.

but something that i could do is take a stock set of secondaries, and just carbide bit the valve to make it smaller... and continue to downsize it until i remove the valve completely. (and each time you make it smaller - do a dyno run to see what the results are)

if anyone has taken a secondary apart, and would like to share some info of how to do it, that would be great. i havent even so much as peeked at them.

 

[jayro]

.
And it might just point us to an approach to achieving the mythical 300 peak hp NA SHO engine.

Are you talking crank HP or wheel HP?

Crank HP can be done. It has been achevied and repeated on a number of set ups. It just takes $$$.

If you are talking WHP then, while I won't say it is impossible, the odds are agianst you. You would need to make 362chp. By looking at the mathmatical formula for HP.....(Torque x RPM)/5252 (i think its 5252?!?), you would have to drastically increase either the Torque or RPM's. With the displacment of the SHO motor, I dont see the torque increasing that much. That leaves you with RPM's. Now you need to figure out how to carry the torque out far enough in the RPM band to reach the 300whp #.

To make 300whp somewhere below or at the 7000 rpm stock redline you would need to make 270-300ft/lbs in that range...270ft/lbs at 7000rpms or 300ft/lbs at 6500rpms.

My sho, while not the most powerful, made a peak torque # of 257 ftlbs at the crank. I would have to make that much torque at 7400 rpms to get 300 whp.

 

[yamahaSHO]

5252.

 

[yamahaSHO]

yamahaSHO, you miss the point of the experiment entirely.

I did not.

It is NOT to justify everyone removing their butterflies just to make some addtional secondary peak hp and torque (and giving up everything down low, as others have already determined)*, the point is to identify whether or not the butterflies serve as a cork in the system, and whether or not reengineering the whole surge tank/butterfly/secondary runner region might be worthwhile. Some have actually built HBBs etc., but to my knowledge there has been no definitive dyno testing comparing them to say SHOshop 41 mm bodies, properly done 40 mm bodies etc.

I highly doubt the increase would be worth the effort.

The experiment can be done with relatively little effort, compared to designing and manufacturing the parts needed to reengineer the transition. And it might just point us to an approach to achieving the mythical 300 peak hp NA SHO engine.

We know what it takes, 23 years later.

auto.guru, are your secondary runners ported in any way? Heads unported yes? You will want to use 2 part epoxy with as long a set time as possible to seal up the shaft openings at the ID (Home Depot has a 24 hr set one), then sand smooth. If I had a spare set of unbored butterflies I would send them to you. Consider other methods such as removable plugs, but try to 1.) make sure whatever you use doesn't get ingested at WOT, and 2.) keep the butterfly wall smooth, no blind holes where the shafts were.



* a dedicated track SHO may wish to reconsider this though

Exactly what you describe has been done. When you look at ditching butterflies (especially on an NA car), it's time to look at building a new intake.

Subarus have a similar bottleneck and have to butterly valves and shafts removed, and opened up considerably and the increase is about 5hp on a stage 2 car (3" exhaust, boost upped to 18-20 PSI).

 

[zblackbeast]

that intake on the SHO was built for the sole reason of keeping the torque band as flat as possible..

Look at Jasons dyno post and you can see how, by with the secondaries, the achieve that. Your better off juts R&Ding your own intake and tuning for that.

If you cat even afford a tuning software, then there is no point in this test.. All your going to see is that your low end torque will suffer and that your going to want your secondaries open at XXXX rpm.

You also need to think about this. You've opened the heads but left the intake unchanged. You do realize that will in theory slow the air down before it reaches the combustion chamber, right? if anything you should have opened up the maf, tb, intake and butterflies etc first.. just my opinion and understanding of the motor..

I are with Jason that you are wasting your time.. I've unplugged my secondaries for fun and it made the car a DOG down low... Boring car..

 

[pjtoledo]

Ive tried the search function but really didnt come up with results. What is the status on whether they are always open or stock? (i personally dont know)

And the reason i said the compressor is because (god help him) my buddy used to use the A/C and routed lines around his intake pipes to "cool" them down. He did this mainly at the track and we always questioned him on what power he lost from the compressor and gained from the cold air. LOL (yes, he might be mentally challenged)but as far as CAI and such, i was just putting the option up there if anyone was curious about any mods they had thoughts of running. I dont know the difference in power from the Y pipes, and ive heard 7-10hp, but i wanted a more definitive # from a dyno run. (like i said... idk if anyone has done such a thing)

you might want to do some research on how a Ford GT is intercooled.


Perry

 

[yamahaSHO]

you might want to do some research on how a Ford GT is intercooled.


Perry

Sandwiched air-to-water IC, like the Cobra?