F2008
Well-Known Member
I hear ya', but ..... he's probably going to want to try it anyway. I better bring it. :laughing :laughing
:beer:
:beer:
I think I remember him saying he don't recomend the spacer with the SVS. You can tune it with the adjustable stacks and get the same results. My memory ain't the greatest so call him for sure. I really liked the SVS on my 260. The wife even noticed a difference on the hole shot and mid-range. Don't think I gained any top end, but took it back off because I couldn't get it tuned to my likeing. Maybe one of theese days i'll fork out the dough for a PCU and try it again.I'll call him and find out if he recommends the 1" spacer for his SVS.
Craig - the horn is installed to minimize the differential pressure needed to get air from the atmosphere into the cylinders. Less differential across the intake means higher pressure in the cylinders which means that more fuel can be injected in the cylinders and still be in the range necessary to support combustion. For the record, I think that the horn is a worthwhile addition. Now for my real $0.02 input.... this is where you see the 2.5s being the epitome of Mercury Racing effort.... My 250 XS has a sharp-edged air plenum that forces air to take a circuitous route into the engine....... so I get unnecessary pressure loss due to the sharp edged entrance to the plenum, plus unnecessary loss as the air has to wind its' way through the plenum.... In contrast, everything about the 2.5 was IMO designed for maximum performance, and that design philosophy extended to the use of an air horn to provide a smooth and direct flow path for the air entering the cylinders. Having said that, you and I might wonder about the usefulness of the spacer. In fluid flow applications, one sees an actual pressure increase downstream of a flow-measuring device (an orifice plate). Perhaps the idea behind the spacer is to allow the air to settle down as one respondent noted on this thread (sorry can't recall who).... so air speeds up through the throat of the horn and slows down after it exits the horn.... so the extra distance from horn to cylinder allows the air to covert velocity into pressure - slowing down will cause pressure to build. So a little more time to slow and "regroup" helps performance by inducing the maximum possible pressure going into the cylinders (for the same reason described above)..... so then if Mercury didn't include it in their design, one has to ask whether they thought the penalty (a few more ounces of weight) exceeded the benefits of additional fractions of a horsepower. That, my friend, is a subject worthy of a beer and a long afternoon contemplating the receipt of your 225PM! :at the barThanks patches. I always wondered what that big "horn" was on some engines I have seen on the different boards. I did not know it was fuel injection. I thought it was some sort of air ram for carbs. I'm not a mechanic but am thirsty to learn all this stuff.
I don't mean to infringe on boater777777 questions and post but am curious also since I am having a Promax built and want the most bang for the buck without getting crazy. I have received good advice from here and other boards but keep options open for other interesting add-ons. Since I already have a Brucato SVS/ACU would it be advisable or not to have the 1" spacer put on?
Hoping some of my questions are OK with you boater777777?
Thanks, Craig :beer:
OK the short answer is yes to the air horn and I don't know about the spacer. As I read your note I thought of one more possible negative for the spacer..... if it makes the front end of the air horn project too close to the inside surface of the front of the cowl, then that too can become the source of a restriction to smooth airflow into the air horn...... Here's a possible path forward to get to a good answer....... Maybe Tony can weigh in regarding the possible clearance issue. If he thinks that it is not an issue, and if the thing doesn't weigh 5 lbs, then I'd say go for it...... of course you have to be (pardon me - Jennifer has to be) the judge of the cost issue for both the air horn and the spacer!Holy Crap Richard!!!.....That was a freakin mouthful. I understood some of it and am waiting for some layman terms to be thrown in as well. Good read. I'll read it a few more times later and maybe digest more of it. And no ill intentions taken as stated in your PM.
Actually, I forgot to ask Tony about that spacer when I talked to him last week about my ACU reprogram. In this explanation was that a yes or no for the spacer in the Promax?? LOL
Craig
Maybe Don will be along soon and add something interesting....I'm sure of it! LOL :relax:
You talkin' bout me?Maybe Don will be along soon and add something interesting....I'm sure of it! LOL :relax:
Sounds like you have a keeper, Craig! Keep it up - it appears that you're treating the girl right!!!!Ohhhh....Richard, I don't have a horn on my engine now nor will my Promax have one. I'm not sure now what I said that may have indicated that. Or maybe cuz someone in one of replies did mention the horn. I don't know. Mine has the Brucato SVS on the front, but questioning the amount of room up front under my cowl had also crossed my mind. OK, now I have to call Tony. I think I know the answer though!
And about my wife, I have to watch what I say to her or she'll go buy it! She was the one that suggested we get more power that's why we're getting the PM. Go figure? LOL
Youll get good results with shaved heads with that combo for sure. The SVS is one wicked set up!! Complemented with the acu wicked! I would realy look at getting the harness to make adjustment at the dash. But I do think that comes with the svs? Youl have to double check with Tony on that one to make sure. If not there 175 I think? Also if your cowl is the original one some put spacers behind the front box to alow more air in. Tony could answer that one for you also. He was a great help in helping in setting mine up.Great read there Whipper!! I already have the SVS/ACU to put on my 225PM when I get it. I think the 280 discussion here was for Alli-drenaline Rush who has a new one to put on his Allison when he gets one. He's wondering how it will do on the XB-21's compared to the larger 3 liters. As for the intake etc. I think I asked if the 1" spacer that Jay smith makes for the 225 PM will work on my motor if I have an SVS installed or if it would hamper the air flow. I need to ask Tony that one.
You DID provide some good info though for down the road easy mods such as the heads getting cut to up the compression and the venting of the cowling to increase air flow. My PM I'm getting will have the stock cowling. Do you know if it has sufficient venting for my SVS?
Thanks, Craig :beer:
Youll get good results with shaved heads with that combo for sure. The SVS is one wicked set up!! Complemented with the acu wicked! I would realy look at getting the harness to make adjustment at the dash. But I do think that comes with the svs? Youl have to double check with Tony on that one to make sure. If not there 175 I think? Also if your cowl is the original one some put spacers behind the front box to alow more air in. Tony could answer that one for you also. He was a great help in helping in setting mine up.Sounds like you will have a great combo. On the 3.0LT think 250xs would be my choise for a 21 but since there the same wight i would go with the 300.