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class6 11-15-2016 04:33 PM

Stainless is a real crappy metal to weld with out future cracking I don't care how good you are.. even with heat treating after.

14 apache 11-15-2016 04:34 PM

[QUOTE=SB;4500865]

Originally Posted by 14 apache (Post 4500863)

Has to be brutal (impossible ?) using a MAP...unless maybe some box that connects to the 8 runners for some vaccuum....yuk. LOL.

Yes one junction block with some hoses to it than take a fuel filter put it in line to the map sensor to smooth out pulses.

Depending on his timing that motor will probably idle 600-800rpm

900HP 11-15-2016 04:34 PM

[QUOTE=14 apache;4500863]

Originally Posted by 900HP (Post 4500855)
Yes but not in CLOSED LOOP ;) very very few ECU's currently have the capability to do 8 widebands in CLOSED LOOP.................... meaning self

You going to run this in Alpha/N or speed density? Or combo?

What is the thought on using 8o2 sensors? I can see on the dyno but not so much in the boat. Just asking and thanks for sharing.

Once you start playing with per-cylinder widebands you find that different cylinders have different fuel requirements at different loads and rpm. If you only have a single wideband you are looking at an average of 4 cylinders, some are lean, some are rich and that can change with rpm and load so you always have to leave your overall tune-up on the safely rich side to compensate for the cylinders that are lean. With individual cylinder control you can run the engine much leaner without the fear of burning it down. This helps with not only overall power but with fuel economy too.

We will be running speed density, Alpha/N sucks. The Hilborn has a vacuum manifold for a map signal and if the map signal is unsteady we can do map sampling where the ecu only looks at the map during a certain number of crankshaft degrees, giving you a smooth average map signal. The electronics package we are running does not suck.

900HP 11-15-2016 04:36 PM


Originally Posted by class6 (Post 4500867)
What idle do you expect to have

I was told I could idle as high as 1000 rpm but we'd like to see it at 850.

900HP 11-15-2016 04:39 PM


Originally Posted by class6 (Post 4500868)
Stainless is a real crappy metal to weld with out future cracking I don't care how good you are.. even with heat treating after.

And yet, nobody has come up with a better way to build stainless headers. Like I said, we looked into making header spacers and putting the o2's there but instead decided to start the waterjacket 2" back from the flange and put the bungs there. IDK......... may be the wrong move but if the o2 bung weld cracks, what about the collector welds, the tube welds, the water jacket welds, the tailpipe welds?

SB 11-15-2016 04:40 PM

Are 02's gonna survive right there ? ie: heat.

Black Baja 11-15-2016 04:41 PM


Originally Posted by SB (Post 4500866)
I have a question for you, which I've asked a few times to others way back, why no collector braces in I/O's ? Like a lot of jet and V drive guys use ?

Some boat builders use braces most do not.

class6 11-15-2016 04:45 PM

Mine always crank near the weld. I fill the header with argon and keep it flowing from a second bottle as I weld to try to cool and keep environment as clean as possible. works a lot better. no cracking since I have been doing that.

900HP 11-15-2016 05:02 PM


Originally Posted by SB (Post 4500874)
Are 02's gonna survive right there ? ie: heat.

Absolutely. My friend Scott has been doing nitrous engines this way with good results. O2's don't like moisture, if we keep the O2 close it will have a better chance of staying dry and it will warm up faster. The O2 will not be in the direct exhaust stream, we will use bungs that put the tip of the O2 at the same depth as the inside of the tube............ the O2's respond just as accurately in this position and stay out of direct exhaust heat.

SB 11-15-2016 05:08 PM


Originally Posted by 900HP (Post 4500885)
The O2 will not be in the direct exhaust stream, we will use bungs that put the tip of the O2 at the same depth as the inside of the tube............ the O2's respond just as accurately in this position and stay out of direct exhaust heat.

This ! Thanks.


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