First Blown Run

[KNOT-RIGHT]

From what I have read on this site this is by far the place to post this.
This is what we did for this season.
Installed mooneyham 10-71 blowers
Installed Richard lee intercoolers
the 540 bowties had approx 100 hours on them prior to installation of superchargers.
I had to lower the compression by means of changing pistons. It had Ross forged 10-1 pistons. I called ross
and had them make me a set of 8-1 blower pistons to the exact dimensions including weight of the prior ones. Tool steel pins and new speed pro rings gaped at
.028. Berry hone was used to finish cylinder walls.
The merlin fully ported cast iron heads were sent out and hardened seats were used with Ferrea icconel valves
New crane springs that compliment the crane 741 roller cams were installed. Cometic head gaskets. Bottom ends were not touched other then removing pistons.
Inspected all ok. (sonny bryant cranks, Carrilo rods)
Pulleys that came with the used blowers gives me a
10.6% overdrive. (Like to have 9lbs boost) (pump gas) Speed Demon 850 carbs came with the blowers.
I boost referenced the power valves (6.5) 80 primary 90
secondary jets. added 1-1 linkage. added 50 cc accelerator pumps and #37 squirters(primary side) to cure flat spot off idle. Installed two heat range cooler spark plugs( Autolite r134) Upgraded fuel system in boat.
Started engines on stand locked timing at 31 degrees
They seem to run good.
12 inches steady vacuum at idle. 1100rpm
Due to circumstances beyond my control My dyno guy never came through This was a very important step
But it ain't happening.
Is there anyone that has ever done this or has similar setup? Any advice? Have I overlooked anything?
I am anticipating a trial run this weekend Checking plugs for sure.
Hows the jets look?
Please respond with any suggestions or advice
Thanks in advance
Gerry

[KNOT-RIGHT]

This is what they look like in the boat.
Please respond
with any concerns or advice
Thanks again
Gerry

[Fiat48]

A good pyrometer setup would be a good addition and help you in tuning. Computech make a digital readout one with a memory.

[Turbojack]

I have same cam in 540 & I can get the motor to idle at 650 rpms in gear & 800 out. Sorry I am no help on where to start jetting.

[KNOT-RIGHT]

Any lower then 1000 rpm and I get a wicked blower surge
the butterflys are set so the transfer slots are showing
a square as even as possible. The four corner Idles are adusted
almost all the way in maybe 1/8 of a turn left on them. They
sound and Idle nice like this. Timing is locked at 32. I may be able to get it to Idle a little lower by bringing it down to 30 Degrees.
Do you think 10 percent overdriven is to much for pump gas.
I am hoping for around 8-9 lbs. With the chiller. The Crane 139741
cam is installed straight up.
Gerry

[KNOT-RIGHT]

Originally posted by Fiat48
A good pyrometer setup would be a good addition and help you in tuning. Computech make a digital readout one with a memory.
Where can I get more info on this?
I imagine it gets welded through the primary on one of the headers?
Actualy the old basset Water jacketed headers I am running
have 1/2 npt bungs welded and pluged in the collectors.
I am thinking wideband 02?

[Fiat48]

http://www.computechsys.com/egtsystems.html
There are weld in bungs or clamp on style for the pickup. Single probe clamp on style is what I use. Only a very small hole is required in the header about 1" from the flange area. It's important to locate the probe where they say to locate it and not further away from the exhaust port.
You could buy one complete unit and an extra probe. Monitor the motors one at a time when tuning.
If you do this there is one thing you have to keep in mind about exhaust temperatures. That is high readings may not be what you think they are till you get a handle on it. High exhaust temps can be rich mixture...and you're actually reading the excess fuel being burned in the exhaust pipe. More prevalent with alcohol but happens on gas sometimes. Combine the exhaust temp reading with your plug reading...and verify the high reading is either fat or lean. Then go from there.

[DetroitJim]

My 2 cents, if those blowers are tight you will make a ton of boost. I run an unstripped Kuhl 8-71 on a 540 and if the blower is overdriven 8% i've seen 12 lbs boost. My cam is only 256/260 so that might be some of it. With the blower at 16% over, the boost reading was a bit higher but I'm not sure since I was going 142 mph at the time. From what I've observed at least from a drag race standpoint my ET does not improve much once the blower is spun beyond a certain RPM. The boost number at high overdrive is mostly heat pressure and not density. Your chillers wil negate that problem though.

[KNOT-RIGHT]

The blower is overdriven in this case 10.6% What is the reduction of actual boost with the chiller restriction?. Static compression is 8.0 to 1. If I use the charts available. Ex.
The Blowershop. They reduce the % as much as 5% with the addition of there Chiller. Looks like its gonna be in the 80,s
up here this weekend. Hopefully Ill get a chance to run it.
I marked the position on the throttles so I can check plugs on the primarys as well.

[KNOT-RIGHT]

Had a Chance to run this weekend. Launched boat off trailer.
Engines Idle at 1100 as soon as you put it into gear it stalls.
Backed four corner idles out 1/8 of turn while they are in gear
seems to help. They idle at approx 700-800 in gear,However
when you put back into neutral the blower surge comes back
then if you bring the throttles up to 2500 to clear it out then come back to idle it is steady. This is where I left the idle.
The run was overall good however the engines where laying down. This was after the first plug check on the primarys which revealed a nice 3/4 black ring around the first thread. and a ground strap which was showing a heated electrode approx.
right at the weld. I removed the two # 6 to the carbs and did a flow check It was spitting fuel. Jumping the electric fuel pump out.
Put boat back on trailer took it back to shop and traced the # 10
line suction side to the tank. Low and behold the pickup tubes
were 3/8 id. With a 90 degree threaded to the very top of tube.
inside there were pen screens totaly pluged with hair and god knows what. I went and repalced the tubes with true 1/2 inch
I/d and threw away the screens. Isnt that what the high flow
Wix filters are for?
Cant wait to try again maybe tonight.
Gerry

[paradigm shift]

Sounds like good progress. Are you running a fuel pressure gauge? Nice catch or save you would be surprised how many forget about the fuel pickups.

[KNOT-RIGHT]

I am embarrassed to say I have been chasing suspected fuel problems with this boat for 4 seasons before the blowers.
I even remember pulling the tubes half way out of the tank and saying wow that just a alluminum tube. Never realizing the screen was in the top where the elbow was threaded to it.
I did a search on my Screen name on some of the other forums that I have posted for support. And just about everything I have asked advice for points to these tubes. Some guys even suggested the cam was the problem.
Well we got another run in and the boat ran awsome.
I marked the position of the the secondarys just starting to open
and shut the motor down at this position and checked plugs.
one motor looked lean no carbon on the last plug ring the other
approx 3/4. I jetted up the primary on the lean one from 84s to 86s.
It gave me approx 3/4carbon ring on last thread. With the drives
in. its about 2600rpm approx 0 boost with a 2.5 powervalve on primarys.
Big water prevented anything over 4900 rpm( 84GPS 7lbsboost). Was beating us up and with the back seat out was scary to see those blower belts just wanting to suck us in.:eek:
There was alot of throttle left The 28 props are way to small.
However the accelaration is awsome the gps dosnt keep up
when your at 55mph and you whacked the throttles it just screams and it mashes you to the bolsters a quick glance to the speedo its still at 60 then it flys over to the 80,s at this point Im already backing the throttles back down due to the airborn hull.
overall it seems to be good.
There is no black soot on transome.
The Idle needs more help. Stalls when you shift into gear
We video taped the cockpit its a absolute joke 13 minutes of
complete shaking. however I was able to get some info from it.
Next run we are going to try the 31 wheels.