NEED HELP. help me calculate exhaust Gas Volume.

[Flyhalf]

This is a nerd post I know
I NEED YOUR HELP.
I explain why i need it.
As you can see I installed a big diffuser in my racecar . I need to move exhaust to avoid burning the carbon fiber.but most important. Gain performance.
So. 2 options.
1. Blow the diffuser below it to increase DOWNFORCE only when on full throttle. ( I dont like it. )
2. Fill the air vacuum behind the car to reduce drag. THIS IS MY CHOICE.

I need to calculate how much( In volume) exhausted gas my 2018 produces.
I did some calculation but i would love some confirmations. Any engineers?

2018 v8 with ported 350mani and MACH1 TB
Headers and 3"catback.

Thanks guys!
Alessandro

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[shogun32]

What's wrong with heat wrap? It's not like you're going for looks...

 

[Flyhalf]

What's wrong with heat wrap? It's not like you're going for looks...

800f gas shooting for 30mins to carbon fiber is not the best . Also this way i can rotate the tip away (laguna pipe) for sound purposes. But most important if i can reduce a tiny bit drag..i mean why not right?

 

[Flyhalf]

Any help here please?

 

[KingKona]

Any help here?

Shogun asked you a question, that was also the answer. Just put a heat tape/wrap/material of some sort on the diffuser and/or the exhaust pipe.

Problem solved.

 

[Flyhalf]

Shogun asked you a question, that was also the answer. Just put a heat tape/wrap/material of some sort on the diffuser and/or the exhaust pipe.

Problem solved.

I also answered that question. It will not be enough. (and is been proven multiple time in the past with people destroying their expensive diffuser. )

Although The question here was another.
Calculate the exhaust gas volume. (and it is not small) to gain advantage for drag.

 

[SheepDog]

This is a nerd post I know
I NEED YOUR HELP.
I explain why i need it.
As you can see I installed a big diffuser in my racecar . I need to move exhaust to avoid burning the carbon fiber.
So. 2 options.
1. Blow the diffuser below it to increase DOWNFORCE only when on full throttle. ( I dont like it. )
2. Fill the air vacuum behind the car to reduce drag. THIS IS MY CHOICE.

I need to calculate how much( In volume) exhausted gas my 2018 produces.
I did some calculation but i would love some confirmations. Any engineers?

2018 v8 with ported 350mani and MACH1 TB
Headers and 3"catback.

Thanks guys!
Alessandro

You could also line the relavent portion of the carbon fiber diffuser with heat shield. Take the exhaust down, and rivet this stuff onto the critical parts of the diffuser

https://www.heatshieldproducts.com/hd-hp-felt-shield

 

[Flyhalf]

No, you did not answer the question.

I don't think you know what you're talking about. You're not even clear in what you're asking, or why you're asking it. You can't even use proper English spelling, grammar and punctuation.

For someone begging for other people's help, you're sure not making it easy or interesting.

Let me clarify something.
I'm italian. So my king sorry for the grammar issues. (please take it this joke with a smile)
I've been helping this community for a long time. Always with a smile and without going further like you are doing here.
The title is : help me calculating the EXHAUST GAS VOLUME.
I dont understand exactly why you are saying on "you dont know what you are talking about. "
What are you referring to?
The point wasn't the wrap. The point was the math of the question i asked on the title.
Ps. Do you roadracing? Are you aware of the rerouting exhaust issues that many have to do to avoid to burn through the carbon fiber?
Please there is not polemic here.
I'm old enough to avoid these things.
Alessandro.

 

[K4fxd]

It's not an easy question to answer.

The K.I.S.S answer is the motor at 100% VE takes in 5 liters of air every 2 revolutions.

 

[SheepDog]

800f gas shooting for 30mins to carbon fiber is not the best . Also this way i can rotate the tip away (laguna pipe) for sound purposes. But most important if i can reduce a tiny bit drag..i mean why not right?

What about side exit exhaust?

Are you really hitting speeds that exhaust flow out the back would have any measurable difference in downforce? Seems like you ginormous wing and diffuser should be doing the job.

 

[SheepDog]

From HP tuners:

In terms of volume you'll need to look at the molar expansion across the reaction. Half of those processes are constant volume, other are constant pressure which makes a huge difference in the pressure and temperature at the end of the cycle. You can not use P=nVRT or any form of it ie (p/v=p2/v2). You need to know how much energy was release, what went into expansion, what when into heat, what was extracted by the engine as useful work, what went into waste energy like heating oil, heating coolant etc. All of these things is going to make a difference in your exhaust gas velocity.

 

[Flyhalf]

It's not an easy question to answer.

The K.I.S.S answer is the motor at 100% VE takes in 5 liters of air every 2 revolutions.

What about side exit exhaust?

Are you really hitting speeds that exhaust flow out the back would have any measurable difference in downforce? Seems like you ginormous wing and diffuser should be doing the job.

We are splitting hairs here i know. (KingKona is it right in english?)
I lost my second national championship by 3 tenths of a second and won one by 1 tenth.
That is why that.
The side pipe is a fair question.
Unfortunately especially here in cali there are a lot of sound limit restrictions at some tracks (laguna. Thunderhill. Sonoma)
And side exhaust would shot directly to the sound meter.
I agree with you on downforce not worth it
blowing the diffuser works on some f1. And it works only on full throttle anyway (when gas are exciting fast)

Now reducing drag is in theory something possible. On the straight you're WOT and that should blow (base on my calculation) something like 200liters per second
That's a lot of air.

 

[Flyhalf]

From HP tuners:

In terms of volume you'll need to look at the molar expansion across the reaction. Half of those processes are constant volume, other are constant pressure which makes a huge difference in the pressure and temperature at the end of the cycle. You can not use P=nVRT or any form of it ie (p/v=p2/v2). You need to know how much energy was release, what went into expansion, what when into heat, what was extracted by the engine as useful work, what went into waste energy like heating oil, heating coolant etc. All of these things is going to make a difference in your exhaust gas velocity.

Thanks for this! Well it looks there are a lot of variable at least for the velocity. I wonder for the volume though.
I guess the only way to measure is test. If i see 1 or 2mph faster then ..i have my answer.
I could rotate the pipes out and up and measure max speeds.

 

[SheepDog]

We are splitting air here i know. (KingKona is it right in english?)
I lost my second national championship by 3 tenths of a second and won one by 1 tenth.
That is why that.
The side pipe is a fair question.
Unfortunately especially here in cali there are a lot of sound limit restrictions at some tracks (laguna. Thunderhill. Sonoma)
And side exhaust would shot directly to the sound meter.
I agree with you on downforce not worth it.blowif the diffuser works on some f1. And it works only on full throttle anyway (when gas are exciting fast)

Now reducing drag is in theory something possible. On the straight you're WOT and that should blow (base on my calculation) something like 200liters per second
That's a lot of air.

Well, fab up a spoiler that goes directly in front of the exhaust pipes, so that when the exhaust gas goes over it, it creates its own downforce. (basically a small, inverted airplane wing that would need to fasten to the cars chassis or body)

Any increase in downforce is also going to increase drag.

Or go full retard and install a proper functioning ground effect on the sides of the car, and get rid of that super ghey diffuser

 

[Flyhalf]

Well, fab up spoiler that goes directly in front of the exhaust pipes, so that when the exhaust gas goes over it, it creates its own downforce. (basically a small, inverted airplane wing that would need to fasten to the cars chassis or body)

Any increase in downforce is also going to increase drag.

Or go full retard and install a proper functioning ground effect on the sides of the car, and get rid of that super ghey diffuser

The little wing above it will do small compare to the 200lbs of DF from a dirty floor with that diffuser (by the way. Designed by a F1 engineer aka Kyle engineers )
And as you mentioned. I have plenty of rear downforce. So I am more focus on drag reduction.
Side skirts will be in place soon (check the zabulon side skirts.)
but some myths :
Real gain on ground effect happens in car 2 inches from the ground with a nice flat floor and is mainly due to the air extraction done by a good diffuser with seal side skirts
By the way. Have you ever seen the car using gigantic fan to suck air out from under the car? That thing was generating thousands of lbs of DF at O mph!

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