Tweecer users inside Please

[final5-0]

I've been fooling around with some air flow values and was hoping some of you would plug in the values from your d logs and we could do a little compairson.

Now I know this is not all that accurate but ...............

It seems to me that the value of about .31 to .32 multiplied by your maximun air flow value gives an approximate rwhp value.

I thought it would be interesting to see what we come up with if the rest of you post up the following info:

rwhp
maximum air flow@xxxx rpm

btw .... my values are 293rwhp & 934.36kg@5730rpm

Later
Grady

 

[5.0_GT_kid]

I'm interested to see what the results are as well Grady.

 

[WhiteDevil]

hmm i never really thought about it that way. Ill fire up my Laptop when i get home and see if i can find a couple data logs in it.

 

[94GTLaserRC]

Subscribing

 

[final5-0]

Subscribing

Come on RC

Don't just subscribe

Put your numbers up

We wanna see

Later
Grady

 

[94GTLaserRC]

My Laptop has been down for awhile.

Sorry..


Just subscribing!

RC

 

[WhiteDevil]

Well doesn look like im getting my lap top tonight. But from memory i think the highest i ever say was 944kg/hr. But my average peak is mid 930s.

 

[Zero Signal]

That's most likely purely circumstantial. Your torque is a function of efficiency and air flow. I don't remember the equations for it anymore though.

I would share some datalogs but I don't have a dyno sheet to test the idea. That and they're on the laptop which has a dead battery.

 

[final5-0]

Well doesn look like im getting my lap top tonight. But from memory i think the highest i ever say was 944kg/hr. But my average peak is mid 930s.

Well John

I was thinking that was about the range of your air flow cause we talked briefly about it in a thread a while back on the Corral.

At 944kg we get a range of 293 to 302rwhp
At 935kg we get a range of 290 to 299rwhp

Since you rwhp is 298, the numbers are in the ball park so to speak.

Even though this little method can be used for a combo's peak rwhp, what really motivated me to think along these lines is the fact that ................

anything you do to show a gain in air flow is a gain in rwhp and having said that ....................

John, remember in a thread a few days ago you said the TFS elbow showed an increase in air flow of about 20kg.

20kg X .31 = 6.2rwhp

Is that value out of line for your gain from the elbow switch .....................

I don't know but I think its close lets talk about it

Later
Grady

 

[final5-0]

That's most likely purely circumstantial. Your torque is a function of efficiency and air flow. I don't remember the equations for it anymore though.

I would share some datalogs but I don't have a dyno sheet to test the idea. That and they're on the laptop which has a dead battery.

John

I agree with your thoughts about how many things could effect an accurate result from using this little method.

As an example, the first thing that came to me was your wot fuel ratio. If your too fat or lean, it goes without saying that your gonna see different air flow values after you put it closer and I guess one could mistake those adjusted values for a loss or gain.

For the most part though, if everything has stayed the same in the combo or tune and you do a mod that shows an increase in air flow, an increase in rwhp should follow right along behind it.

Later
Grady

 

[a50sn95]

1406.952 x .31=436.139.
EA (EEC Analyzer) says 597.
Oh, I don't have a dyno test to verify, so take these with a grain of salt, for now....

 

[WhiteDevil]

Well John

I was thinking that was about the range of your air flow cause we talked briefly about it in a thread a while back on the Corral.

At 944kg we get a range of 293 to 302rwhp
At 935kg we get a range of 290 to 299rwhp

Since you rwhp is 298, the numbers are in the ball park so to speak.

Even though this little method can be used for a combo's peak rwhp, what really motivated me to think along these lines is the fact that ................

anything you do to show a gain in air flow is a gain in rwhp and having said that ....................

John, remember in a thread a few days ago you said the TFS elbow showed an increase in air flow of about 20kg.

20kg X .31 = 6.2rwhp

Is that value out of line for your gain from the elbow switch .....................

I don't know but I think its close lets talk about it

Later
Grady

Wow, i really do think that maybe in the ball park area. This is a really good way to make sense of the kg/hr numbers. And what the changes might mean.

 

[95BlackTan50]

Grady,

During my last dyno run I had the following:

Peak HP = 212
RPM = 5676
MAF = 811.2634 kg/hr
Ratio = 0.2613

My numbers are probably different since I get more transmission loss between my engine and my wheels with my AODE.

I wonder if I would get 251 RWHP with a T5? (0.31 * 811.2634 = 251.49)

Anyone out there with a similar combo and a T5 that has 250 RWHP?

Interesting post Grady.

Barney

 

[final5-0]

Grady,

During my last dyno run I had the following:

Peak HP = 212
RPM = 5676
MAF = 811.2634 kg/hr
Ratio = 0.2613

My numbers are probably different since I get more transmission loss between my engine and my wheels with my AODE.

I wonder if I would get 251 RWHP with a T5? (0.31 * 811.2634 = 251.49)

Anyone out there with a similar combo and a T5 that has 250 RWHP?

Interesting post Grady.

Barney

You do bring up a point I had not thought about which is the type of trans used. Since we are talking rwhp, it does need to be considered.

A rule of thumb for drive line loss is 15% for stick & 20% for auto.

If we take your 212rwhp and look for fwhp I get about 265 fwhp.
265fwhp with a stick trans is about 225rwhp.

I feel pretty comfortable with the 225 value as an answer to your Q but it has nothing to do with our topic of discussion, lol.

This is where I confess to you all that math was not and still is not one of my strong points, lol.

Since there is a 5% difference of loss between the two drivelines I tried to adjust things by that amount but it was no glory as the numbers would not fall into place.

Another thing that is interesting is the difference between the .31 and the .26 number that you show to work in your combo. It is a 17% difference! Why that is so different from 5% is beyond me but it is over my head and I don't even have a clue, lol.

I would like to find others who use an auto trans and see it that .26 value would work for their combo like it does for yours.

If anybody sees where I missed something ...... set me straight

btw Barney

I did some testing with the Startup OL & Base OL fuel tables to see if you made a pull before things stabilized what might happen. You were 100% correct in your suspicions. I made the greatest load row in the base table match my stabilized table and everything was as it should be if you made a wot blast at say 30 seconds after starting the car.

Later
Grady

 

[type911]

Not accurate for me.

last dyno = 380rwhp

1436x.31 = 445
1436x.32 = 459

I have blow by issues however.

I will be working on it this winter.

tired of replacing v/c gaskets
and breathers just throw oil on the headers.

smoke shows are supposed to be done in the rear right?

 

[final5-0]

Not accurate for me.

last dyno = 380rwhp

1436x.31 = 445
1436x.32 = 459

I have blow by issues however.

I will be working on it this winter.

tired of replacing v/c gaskets
and breathers just throw oil on the headers.

smoke shows are supposed to be done in the rear right?

As for the .31 to .32 value, I have no idea where it came from or how it was determined. Maybe it is for na only but I just don't know.

I simply asked the guys on the Tweecer site if the air flow values could somehow be converted to horsepower and one of them replied with the magic value. I used that value on several combos and saw it seemed to be close and just thought I'd see what all of you had to say about it.

Later
Grady