wanna kick it up a notch

[F2008]

I hear ya', but ..... he's probably going to want to try it anyway. I better bring it. :laughing :laughing

:beer:

 

[BigRedAlli]

I'll call him and find out if he recommends the 1" spacer for his SVS.

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.

Sounds like you should have a stout 225 when your done...:cool

 

[Allyfishing]

I hear ya RA. I feel confident that the way the engine will be built that I have the option if I wanted to to turn it up high to experiment and not be worried. I read a real good article on the SVS and the ACU on a 225 Promax with little else done except the basics like the pistons, oiler off and bearings and on top they gained about 3-4 MPH.

Wow, hullbilly, that's a great testament to the 225 Promax stock to turn it up to over 8G. I realize that mixing at 32:1 is good insurance but you hear about so many guys blowing Promax's and blaming it all on the side pinned pistons. There must be more to it. My hat's off to you also for being a great racer!! You're right, that is a bunch of weight for a drag. You pull away real strong on those videos.

thanks BigRed. I'll have to give Tony a call and ask. I have to send him the ACU to have him reprogram it anyway when the Promax comes in. I have it on my 200EFI now and never fooled with it. Tony set it for the compression on the engine so we just hooked it up along with the SVS and had fun. It made the 200 real snappy. the PCU that Tony has, my understanding, it can be programmed on the fly while driving. Too technical for me.

I can't wait to get to the water with the new set up and spin some of F2008's wheels. I hope to have one of TBucks Hydromotives by then too. I have not been able to stop thinking about that Trophy you have too. Admit it, it's gonna be too small for your rig!! LOL

boater777777, sorry to have gotten away from your question, but I think with all this feedback you have some good pointers. Like hullbilly's stock promax, get rid of the stock oiler, premix, get the ECU reprogrammed or put out the money for one of Tony's SVS/ACU systems!!

Thanks, guys!! Craig :big grin

 

[Jus' Giv'r]

Wow, what a great read this was for me. Currently, I'm in the same boat (couldn't resist). I have a stock 1997 225PM. Low hours, exc compression, 20" bass mid, sporty lower on a GSE. Only thing I did was remove the oil injection. I run the Alisyn Oil. It runs about 92 with a 29SRX by DAH. Maybe a few more MPH, but I would be on the edge. I would like more lower and mid-range punch and be able to reach 95-100 easily.
I have a couple of other posts going but never really got into the PM mods.

So I was thinking, changing my bass mid to an offshore with one piece exhaust tuner, lightweight flywheel and send my ECU to Simon. After reading here I don't know if I'm on the right track?

Then after adding up the cost, I was thinking about selling my PM (I have a buyer) and getting a 280 with 280 electronics because I understand they can shift and idle better than the 260. Now, after reading this tonight, maybe I'm back to mods on the PM.
I Just don't know???

 

[Allyfishing]

HI Jus'Givr'.......I hear ya. Great advice here. From what I get out of this read and other posts and talking to people on the phone like Tony Brucato, Todd at Hydromotive and Eric Simon and others over the past few months is the best bang for the buck if your PM is stock and real healthy is to up the compression, with the heads and add an SVS/ACU. Of course remove the oiler and some of the electronics.

Also told that if it needs to be freshened up then install vertex pistons, metal cage bearings etc. etc. in addition to above mentioned.

Eric Simon told me that has great success with the 16 amp charging system and lightweight flywheel and then adding his belt driven alternator kit on a Promax. Ya need the Alien style cowl for it to fit under the hood. He had done it to many motors and picked up a few more MPH.

Here is a good read: http://www.hydrostream.org/ArticleArchives/DCProMax/DCProMax.htm
And another one: http://www.brucatosvs.com/2l_1article2.html

Good luck, Craig :big grin

 

[Alli-drenaline Rush]

Thanks 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:

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 bar

Richard

 

[Allyfishing]

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:

 

[Alli-drenaline Rush]

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:

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!

I'd like to hear what others have to say. I could offer a judgment on what a spacer would do for breathing for my motor - I just don't know if the 2.5 EFI Sport is similar dimensionally to the 225PM (like I said I'm late to the hi-perf boating scene!!!!)

BTW - If anyone has an XB2002 that they'd like to loan me so that I could mount my motor and test these theories, I'd gratefully buy him a six-pack for the effort!!!!!


Richard

 

[Allyfishing]

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

 

[hullbilly]

All neat points, and pressure is a great conversation piece for engines in general. I can tell you that the racing crowd has pretty much landed on air velocity being much more beneficial than total flow.

A 2 stroke engine, when boiled down, can be looked at like an air pump. But, it can only pull so much volume in and get so much volume out. Modifications that slow down air velocity have proven to be losers on the race course in general.

I believe the spacer was added to provide more even distribution of air to cylinders 1,2 and 5,6. With a horn setup, air is straight-line directed into cylinders 3,4. Hence the theoretical advantage of the SVS where air is directed to each set of cylinders independently and appropriately. However, that increase in air must be capable of being utilized by the block, which suggest that SVS may not be an across the board, no brainer.

Take the laser injection system as an example. The air comes in, hits the intake wall and then travels the opposite direction into the block. Makes no sense regarding flow. It is however, an awesome system, capable of impressive performance. I believe this is due to air velocity.

Please consider my opinions from a racer's standpoint and not a top end perspective.

Good thread!

 

[F2008]

Maybe Don will be along soon and add something interesting....I'm sure of it! LOL :relax:

You talkin' bout me?

Way too intense for me :shock:

I'm practicing one of Mark Twain's (I think it was) philosophies, "Better to keep your mouth shut and appear stupid than open it and remove all doubt" :wink

 

[Alli-drenaline Rush]

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

Sounds like you have a keeper, Craig! Keep it up - it appears that you're treating the girl right!!!!

 

[whipper]

Best bang for buck. It all boils down to this because if your planning on spending over 2000 bucks that would be the differance from the 225 to a 280. A good strong stock 225 is worth between 4500 and 5500. A good 280 around 6500-8500. You would have to do a lot more than spacer,ACU,Pistons,Heads,SVS to beat a 280 in performance. Even with all these mods you will still have a hard time braking the 100mph mark in a GS for instance. Well if you put a high rake 32Cleaver on at sealevel and raised the motor above the pad a touch you might just touch it. But a 280 with do 103-105 on most good days. 100 with passangers!!

I realize your talking mods for a 21 so the chepest way and bang for buck is only a few things that youll realy feel while boating that dont hamper reliability at all. They all have been mentioned hear. In a nut shell with out breaking the bank this is what I have after extensive reserch talking to many racers and top notch builders like Jay and Lee Davies,Tony at Brucato, Brian&Mark at Quality Marine, Todd at Hydromotive ect.. Every one agrees the 225ProMax is one great all round user friendly motor stock! HullBillys racing last season is testoment to that for sure spinning a side pinner to over 8 all season with out a break!!!WOW! I think the rev Limiter is the single most value added change one can make besides premixing off course.

The two best ways to do this are like Hullbilly send it to Shawn at Rapair or a Brucato ACU. Personaly 7500 is a good limmit and has more of a saftey net than over 8.

Im sure most will agree the higher you go with steel bores the hotter it gets that will shorten the life. Good oil is a must. Most engine guys also say they dont see 7300rpm premixed with a 225 a really big deal. I prop for this RPM even though I have a 7500 rpm Limitter on my Brucato acu just to be safe. Though have done 7500.

The second bang for buck thing to do is heads. For 150 bucks Jay takes your ugly gray heads and turns them into a work of art! The pic on his web site of the heads polished Aluminum and black is stock what you get back!! He also bevals the bores for no extra charge. Great deal fast turn around and more comprstion. Mine are 33CC gave me 10-12PSI at 2200ft.

The third if you have an Aftermarket Alien cowl is drill holes in the cowl! The after market ones from Bobs or Dimond dont have the same air flow built into them like the stock ones from Merc!!! I could not believe what a differance this made letting air flow better to the intake!! HUDGE CHANGE in performance.

This is also were the Brucato ACU was benaficial over a non programable one. Tighter heads like to eat and respond greatly to an incrase in fuel. I turned up the fuel delivery and felt the tourque change noticably over stock out of the hole and midrange and dont realy notice an increase in fuel consumption. Just a little made a lot of differance.

Thats it! Thats all i would do or i would be spending more money that could go to buying a 280. If you went with a SVS System and had some port work done along with the above changes you could give a 280 a bit of a run for there money. But for me I cant spend another 1000+ bucks and still not see 100mph regularly with out a real 280. Theres some stout 225,s out there that realy do great aginst bigger motors but the bigger motor does it stock!

The extra hole shot and mid range now comes from the ability to run smaller pitched props. Thats the whole goal hear. Thats all your trying to accomplish by doing these changes.
By increasing the rpm to 7300-7500 from 6750 you can spin a smaller wheel higher. The get it there you need more touque. Thats were the heads come into play. The air flow as mentioned also is inportant. You dont want to choke off the air supply. Try running with a noose around your neck youll be faster longer if you can breath.

You now dont loose any top end because of the higher rpm. But high rpm is just part of it. On the 21 youll benifit from tighter heads also. SVS System!! WOW oh ya baby if you can aford it go for it. I cant justify it personaly over selling my motor for a bigger one but ya thats one of the big daddy things to do for sure! Youll have more every were with one of those bad boys from what Ive been told. Theres a evaluation on what the SVS does on Scream and Fly off the home page. Also for the Brucato acu and Rapair mods. Good reading. Sorry for the long post. I drank to much coffee tonight!:relax: James

 

[Allyfishing]

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:

 

[whipper]

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.

 

[Allyfishing]

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.

You've been a big help with the advice here. Tony has 2 boxes. The ACU (what I have) can be mounted under the cowling on a stock PM and to the side of the SVS so as not to restrict air flow to the SVS. He provides the brackets for this. It is user programmable with dials under the cover. The other is the PCU which I think you are referring to that has a harness and a control box to mount in the drivers area for on the fly adjustments. It evens comes with optional software for more user programming if I remember correctly. When I had the ACU on my Astro it came with a 6'extension harness cuz it would not fit under my XR4 cowling so I mounted it in the bilge area. I had to do that with my 2+2 also since I transferred my engine over when I bought it. With the PM I'm getting it will go under the cowling as intended.

I'm not sure about this statement though....."Also if your cowl is the original one some put spacers behind the front box to alow more air in. " What are you referring to there?

Would I have rather had a new 250XS or 300 on my 2+2 when I bought it????...You bet......but the money I saved allowed me to get into my Allison and that's all that mattered at the time. I'm a happy camper!! Now I'm able to get a more High Performance engine with the 225 Promax over my modded 200EFI at a fraction of the price. And Mr. Allisons tests with the 2+2 and the 2.5 Liter 225XS is impressive enough for me for now. Don't get me wrong....if I ever hit the lottery or for some dumb reason someone gave me a bag full of money I'll march right on down to the nearest Merc Racing dealer and put the biggest baddest power on available!! LOL!!

Thanks Whipper
Craig :beer:

By the way, how's the weather up there? We just got a few inches of snow but South of Pa got up to 2 feet. Like Washington area and Virginia. Go figure.