Help! Exhaust 101 questions!

[38flattie]

Looking for a little advice here.

We don't have time left to split the siamese ports like we wished, and need to get the exhaust figured out.

I can't find anyone to make the collectors I need, so I'm exploring some options.

I don't see anything in the regs, that say I can't run the exhaust out the top of the hood. I could run individual stacks straight up, or straight out the sides.

From experience, what are the pros and cons of this?

My other issue is EGT sensors. I have one wise band for each bank, and while not ideal, I was going to put one in each collector.

If I run individual stacks, should I just put one in the anticipated hottest cylinder on each side?

If anyone has a better solution, I'm sure listening!

Thank you in advance!

[dw230]

Blown engine, I am told the type of exhaust does not matter because you are pushing the spent gases out of the engine. If you go with indivdual pipes make sure the free ends are tied together.

DW

[RichFox]

On the Packard I ran the center pipe as a large, port size + a little, all the way out. I connected #1 and #4 (Per bank) near the end. Could have gone all the way to the end and split the pipes and welded them together as sort of a collector. But didn't. I don't think running the pipes like a mud bog or destruction derby car works well with the rest of your effort.

[Hans Blom]

It's definetly directed Away from the salt...

[38flattie]

Rich, I think the way you did the Packard may be our best bet. I'll let you know.

[John Burk]

Two negatives come to mind , looking through heat waves and possible oil on the windshield .

John

[Jonny Hotnuts]

What Burk said. The more I read the more I think that guy has a clue what hes talking about. You could also end up breathing some exhaust.

Also.....


Depending on the vehicle you can induce turbulence over the hood and increase drag. Some will argue that the hot air will flow better then cold.....I say this would be true if the hot air was laminar. Clearly exhaust will be far from laminar. On second thought.....disregard most of what I say as its hot air!

And.....

If the fuel-air from the carb-manifold is divided into 2 banks ....right and left (or even better not divided and from one source) I would think that all cylinders on each side would have relatively close EGTs. Clearly injected motors with the ablity to have different AFR per cylinder would be more susceptible to varied EGT. My knowledge of tuning is limited to 11K+ RPM injected 4 bangers (and limited at that) and may have zero relevance to your application.  


~JH


 

[jimmy six]

Don't put an EGT in the collector it's a waste of time and energy. Follow the manufactures reccommendation on it's placement. Some are as close and 2" and as far as 4" from the flange. If it follows what I have learned about on siamese exhaust ports I would put it on the rear most single exhaust port as that "should" be the hottest. Good Luck

[jimmy six]

PS: Tut a piece of tape over it after 1500....by then it's too late and you don't want to shut off anyway................JD 

[38flattie]

The car is mechanical injected, but blown, so all the fuel/air is from one source.

I think I'll run a 2.5" on the siamese ports, directly out the side of the car. I think the outside cylinders can be tied in like Rich did. I'll use a 2.5'-3" swage at the end of the center run, and tie the outsides in there.

Based on what you guys are saying (and it matches the manufacturer's recommendation) I'll put the EGT's in the cyl 7 and 8.

...AND I'll cross my fingers!

Thanks for the advice guys!

Oh, and no tape Jimmy....