Engine Dyno Myths...

[auto.guru]

Im in the process of building my 3.2L and should be done fairly soon now that i have all the correct parts. I am in the Engines program at Fox Valley Tech College in Appleton WI. We have a dyno that people can use for a few pulls with their car. Its $90 for 3 runs, and you are allowed to modify things inbetween each pull. If anyone is interested and lives in the surrounding area dont be afraid to send me a message.

My plans for my 3 pulls....
Engine will be at normal operating temperature with Mobile 1 synthetic 5w30.
Exhaust will be Y pipe but nothing after it.
A/C has been deleted, so there is no added friction from the compressor.

1st Pull
acurately measure the torque and hp with the secondaries ALWAYS open. By this i mean hooking them up to manifold vacuum so they are never shut.


2nd Pull.
return the secondaries in the intake to NORMAL operation. this should put any myths for HP and Torque readings to rest. Thus we can accurately see the difference from the two pulls. This should solve multiple questions and theories about which set up is better


3rd Pull
The real difference between a stock Y pipe (which i currently have) versus the aftermarket high flow Y pipe. Since my engine build is quite extensive, i dont have the money to buy an aftermarket Y Pipe. I would be more than willing to change it out if someone would borrow, or sell me one for cheap (highly unlikely).

If there are other things you would like to see the difference of between pulls 1,2 and 3, please comment and let me know. I was also thinking about the air induction system (N/A) and how much power would be gained by going to a CAI or Ram Air induction system. Another thing as i mentioned before is the A/C Condensor Compressor. If someone has a junk one lying around and would like to borrow it, to see the added difference of an A/C delete, let me know.

Anything else just post. This may have, or may not have been done before but im willing to put these 3 pulls to good use.

 

[LOUDSHO92]

How the secondaries function is well known. There are even a few dynos running around showing the secondaries fully opened and fully closed. If you want to go for it thats great but you wont be putting anything to rest.

The compressor doesnt add any friction unless engaged.

 

[auto.guru]

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)

 

[yamahaSHO]

Secondaries?



I'd skip the Mobil 1 and go for the Shell Rotella T6 as it has LOTS more ZDDP.

 

[auto.guru]

i was looking for documented proof of having the secondaries always open versus functioning normally. The difference in HP and Torque between the two with absoluetely no other modifications to the car, and both dyno pulls performed back to back.

 

[yamahaSHO]

My graph above should be enough proof. I opened the secondarie at where peak torque for a stock SHO would be. Tuning in between would be more beneficial.

 

[LOUDSHO92]

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)

I do not have the dynos but I have seen them before where they are either opened all the time or closed. You can even do the test. It wont take a dyno to prove it. Just do it on the street and you will feel the difference.

YamahaSHO dyno is good evidence. You can see the drop off with them opening so late.

 

[auto.guru]

i just heard rumors about a higher overall low end torque in sacrifice for top end speed.... but the graph does show a lot

 

[shobote]

Dyno runs with a high flow y pipe have also been done; IIRC 14 hp. Question, why not save the $90 cost for dyno pulls, and put it toward buying a y-pipe ? The best bang for buck upgrade for the MTX. Dyno pulls do nothing for performance, and unless you buy a tweecer or equivalent you can't change the tuning anyway.

 

[zak]

It would be far more intesting to run the stock setup, then swap out to a set of secondary butterflies that have had both the plates and the shafts completely removed, and the resulting holes sealed. Then look at the height of the "secondary" torque and HP peak.

 

[yamahaSHO]

I highly doubt the increase would be worth the effort.

 

[Toolman]

My butterflies will be gutted and bored. I'll dyno both them, and stock. The big spinny thingy might skew the results some, but I think it will still be interesting.

 

[auto.guru]

if you would like to send me a pair of butterflies gutted like you say zak, ill do it. Because i built this 3.0 in to a 3.2 at school, i am allowed to put it on the dyno and see my engine work and the power it puts out.

The dyno is open to the public for $90 / 3 pulls.

and 14hp for the Y pipe? damn

 

[zak]

I highly doubt the increase would be worth the effort.

If you take careful measurements of the intake tract at various points you will find that the lowest cross-sectional area is at the butterfly crossrod. This includes 40 or 41 mm diameter overbored bodies (assuming the butterfly is present).

What are you willing to wager that its worth greater than 5 hp in this particular experiment (if autoguru choses to pursue it)?

On edit - this young man wants to dyno test something new that has never been done before. The butterflies closed vs open for entire run has been done, with and without crossover has been done, various "intakes" ahead of the main throttlebody have all been done, Y pipes, various exhuasts have been done numerous times, extrude hone, BBBs, with horns or without have all been done before. Why not try something new?

 

[yamahaSHO]

If you take careful measurements of the intake tract at various points you will find that the lowest cross-sectional area is at the butterfly crossrod. This includes 40 or 41 mm diameter overbored bodies (assuming the butterfly is present).

What are you willing to wager that its worth greater than 5 hp in this particular experiment (if autoguru choses to pursue it)?

I can do that without modifying anything physical on the engine.

5 hp for the MAJOR loss of low end torque on a motor already lacking it... I stand by what I said. I chose my words appropriately.

 

[Toolman]

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.

 

[yamahaSHO]

Tim, I disagree. Turbo or supercharging a car has very much been worth the effort.

 

[Toolman]

Smiles per mile quotient is way up!

 

[hawkeye18]

If you have the ability to alter the point at which the secondaries open, then doing a dyno run with the secondaries wired shut and one with them wired open, then overlaying the two graphs, will show you precisely where you need to open them. Very few SHOs still benefit most from a 3950rpm opening point.

 

[yamahaSHO]

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.