Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   Magnum Marine (https://www.offshoreonly.com/forums/magnum-marine-63/)
-   -   28 Arrow Magnum (https://www.offshoreonly.com/forums/magnum-marine/158374-28-arrow-magnum.html)

Mange 07-03-2007 05:11 PM

hi Erik, my friend and engine builder Johnny do always use the car headers during the dyno. And they use to work fine. But this time they were little to small. Even Johnny said that. The exhaust fitings in the dyno rig fits car headers better than the marine headers. Thats the reason. Thanks for finding this project intresting. /Mange

biomech666 07-04-2007 04:54 AM

Great numbers from the Dyno :woohoo:

I hope you are satisfyed :D

Congrats Mange...
...I hope to see some pics of the engine in the boat tonight :)

Mange 07-04-2007 05:11 AM


Originally Posted by biomech666 (Post 2186919)
Great numbers from the Dyno :woohoo:

I hope you are satisfyed :D

Congrats Mange...
...I hope to see some pics of the engine in the boat tonight :)


Thanks Biomech,
I think we going to put the motor in tommorrow first, but we never know.....

here's a little movie...
http://www.youtube.com/watch?v=swJRTd8erh0
(sorry for bad photo quality..)

erik_plus8 07-04-2007 05:43 AM


Originally Posted by Mange (Post 2186564)
hi Erik, my friend and engine builder Johnny do always use the car headers during the dyno. And they use to work fine. But this time they were little to small. Even Johnny said that. The exhaust fitings in the dyno rig fits car headers better than the marine headers. Thats the reason. Thanks for finding this project intresting. /Mange

Hi again! OK, I see. To be honest, I think there should be a significant number of horses to be released with a properly tuned manifold... A few percent (~5-8%) in volumetric efficiency can easily be gained, and that will translated to the same percent in max power, which on this level is quite a lot...

On the other hand, that will only be a "dyno number". In the boat you will already have those horses available since you have what looks like a nicely tuned manifold there...!!! :cool:

Mange 07-04-2007 07:04 PM

1 Attachment(s)
tonight my buddy Johnny and I droped the engine in the boat. I have alot job to do but it feels great to have the engine there. We had to twist her down!! Its not a plenty of space there.....

JesseDC 07-05-2007 05:05 AM

Keep up the good work!
Looking forward to see her wet :)

BR
JesseDC

Mag27 07-05-2007 01:30 PM

Mange,eng.looks great in the boat.Got a few dumb questions.That 572,was it a GM crate eng or somthing somone had built?Also what is the comp?How i wish i was on fresh water ware i could use allum. heads and be able to kick up the comp. without having to use 110 racing fuel.When i put my first 540 together with the 13 an half pistons it was like adding 5# boost compared to the 10 to 1s i use now.

Mange 07-05-2007 07:21 PM

hi Mel! She is crate and we had her in my 3 man Pantera last year. I really dont have the comp nr but xx ithink. Since we replaced the pistons (venolia) we are lower than xx now (i dont really know)!

tomas_wallin 07-06-2007 07:15 AM


Originally Posted by Mange (Post 2188402)
hi Mel! She is crate and we had her in my 3 man Pantera last year. I really dont have the comp nr but xx ithink. Since we replaced the pistons (venolia) we are lower than xx now (i dont really know)!

According to GM Perf the C/R is 9.6:1 in the crate 572/620.

Mange 07-06-2007 07:43 AM


Originally Posted by tomas_wallin (Post 2188731)
According to GM Perf the C/R is 9.6:1 in the crate 572/620.


Yeep, thats correct. I'll ask Johnny what c/r we have now....I know 8 something...


All times are GMT -5. The time now is 12:33 PM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.