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View Full Version : How Much is Too Much WOT?



Marlin275
10-26-2002, 03:01 PM
Here is a question there might be strong opinions about?
How much WOT ( wide open throttle ) is too much?
Based on regular everyday use, not race conditions!
I don’t feel good about more than two minutes at
WOT with a stock 350. I do want ten years out
of this motor.

In the 1965 era with the Miami-Nassau races,
the Holman-Moody Ford race engines were
insured for 1 hour at WOT, but multiple times longer
at 75-85% of WOT. Things different now?

I think the answers might be different for stock or modified...etc..

Jamesbon
10-26-2002, 04:36 PM
It all depends on many, many factors. My original (well, original to me) 350 in my GT lasted 12 years. I remember several occasions on the Chesapeke Bay traveling from Sandy Point State Park to Red Eyes Dock Bar at WFO for an hour at a time. I've also had engines last less than a season. (loose head, failed head gasket) If your equipment's in good working order, in my opinion, you should be able to run it WFO for hours at a time. I run my stuff hard, very hard. That's what it was meant for.

BigGrizzly
10-27-2002, 07:15 AM
There are too many factors. For exhample my 18 Corsican has 125 mor Hp than it origionally had from H&M. This puts stress on the motor which decreases life. Rpms also do. A stock 250 HP 350 Chevy can take the 4500 rpm for quite a while. I usually cruise at between 3000 and 3500 max on any boat with a I/O or inboard power.I'm not saying that I havn't WOT for 10->15 min but that covers a lot of realestate in a hurry, and it isn't that important to me. I have also used the best stuff there in a great motor just to have it drop a $48 valve and cause a big heart break. that motor was well cared for and not beat and only had 185 houres on it.

fasttrucker
10-27-2002, 08:50 AM
i tend to run 4000rpm a lot.one guy here i know of runs wot all the time.i dont want a motor thats only capable of wot for "bursts" that why iam thinking of heads+cam instead of supercharger. :confused:

Barry Phillips
10-28-2002, 08:27 PM
In the water conditions I run in, WOT would hammer both me and the boat to death in that order. I usally run between 3000 and 3500 rpm, and rarely hold WOT for more than 2 min. Just to many factors, such as wakes, other boats, water conditions etc. Allthough small blocks such as my 350 can handle rpm pretty well I do not feel you can run a V8 like an 2 stroke outboard. If you want your motor to live 10 years or more change the oil and give it break now and than.

SO-SLO

GEOO
10-28-2002, 08:54 PM
Just put more power in it. Then you don't have to worry about running her too hard, because it's not possible!!! (kidding)

I run 4000rpm for long run's.

Bryan Tuvell 33ZX
10-28-2002, 09:16 PM
Great post, I tend to run 42 to 4500 RPMs for very long periods of time. Most in my club are twins, so I need the R's to hang at cruise (50 to 55 GPS). Only go to 5200 to make a move, but sometimes that is up to 2 to 5 minutes.

The Poker Run ROADTRIP and I did was 4200ish RPM's for 5 hours straight.

I am curious to see more "honest" responses, I have also wondered the same question.
Is 4500 RPM that much safer/better than 5250?
I change oil/filter and drive every 25 to 30 hours.
On the other hand, my friend ran 5600 RPMs WOT for five hours, with 500's worked....
Thanks
Bryan

b.guggenmos
10-28-2002, 09:42 PM
In Washington we used to run a race from Olympia to Roache Harbor in the San Juan islands. I had a 88 Classic 22 Testarossa with 460 Ford and King Cobra drive. Ran wide open most of the 2 1/2 trip except for wakes and some fog in the straight. RPM was around 5000. Unfortunately after I returned I noticed some black soot on the right exhaust and transom. It was also 2 qts low on oil and number 8 cylinder spark plug was thick with deposits but still running fine. I looked in that cylinder with a bore scope and it was scored bad on the thrust side of the cylinder wall. Ended having to rebuild the engine. So in hindsight I guess that was to long but what a ride. Most engines are much stronger for full throttle runs than people give them credit for. As long as it has a prop that keeps the engine in a good power band area I say let her rip. By the way this boat is now listed for sale in Seattle for 16k and if it is in the kind of shape it was in 1994 that is a good deal.

GeneD
10-30-2002, 07:36 AM
I used to run about 17 miles WFO in the Indian River when I lived there oh so long ago!
Forrest Coile can attest to this insane abuse of my 350 Mercruiser.
Of course, that motor is now scrap iron...

harbormaster
10-30-2002, 08:09 AM
I saw it first hand Gene...

Forrest
10-30-2002, 09:00 AM
Mee tooo! eek! eek! :D

Hay GeneD, do you think that the time I hooked up with you almost five years ago and took the famous lounge hopping ride in 007 (at WFO) on the Indian River, may have been the very first Donzi event made possible by this board?

Craig
10-30-2002, 09:16 AM
The guy on the DONZI 18 review video from a couple years ago makes a statement about the 300hp 350 w/ Bravo while he's running at 55mph and at 3800 rpm's: "This boat could run hear all day" implying that hours of running at that speed should be no problem. Sort of a generic remark, I know. And I know thats not WOT, but hey, it's something! Figure most cars get a lot of running (once in high gear) at much less rpm's than that. Of course marine engines are made to handle more than car engines. What am I trying to say? Not really sure. Run 'em hard and have fun! They build new engines every day!

GeneD
10-30-2002, 01:50 PM
Scot,
Forgot you had the ride from hell that one afternoon.
I told 'em, "I ain't dealing with this sh*t all day, hold on...we're going for it." And proceeded to take some rather nasty water for about 30 minutes. Could have been longer. I'll bet Scot thought it would never end. Hey Scot...'was it fun?'
Forrest...could be right big man! Gee, maybe we should have made a t-shirt!

BigGrizzly
10-30-2002, 06:00 PM
Bryan the answer to your question is yes. the piston speed is the concerning factor as well as the valve system. think of the theoritical weight of the piston changing directions at 4500 vs 5200.