JasonSmith

tunertech - you know what you are doing!

articfriends

iTrader: (1)

Years ago I switched to lightning headers from merc exhaust when I had a blown 502,I was expecting a 400-600 rpm top end gain (as claimed). I gained ZERO top end rpm's and a slight mid range tq increase,needless to say I was less then thrilled. I did have the ecu reprogrammed several times at the time but it was already reprogrammed for the blower. I think the stock exhaust port (I had merlin heads at the time which have close to stock exhaust flow numbers) doesn't flow too great so the exhaust doesn't give you the kind of gain you would see on a good flowing head. The thing that does suk on lightning headers more than anything is there is no good way to mount a 02 sensor to see what your afr really is to tune it properly,Smitty

CAL MAN

why not just give out free copies of mefiburn so no one is capative to any one. I'm sure you spent alot of time developing your soft ware, but tuners spend alot of time on there cals also. Some eng builders don't even want to give there cam specs out. I like some of the featurs of your stuf, but not sure about the free love on the cals. I have alot of time "money" invested on the dyno and water in the cals that I have, not ready to give all that away.

Dock Holiday

Well there you have it from three of the best in the industry.

Whipple - Hardin Marine - Mark Boos

I think it is very wise to cover all your bases when doing modifications to any marine engine. What is $350.00 when you are talking tens of thousands invested in your engine, down time and being on the end of a tow rope? Good cheap insurance in my opinion and hopefully as Dustin pointed out you will see some additional gains in your investment.

Mark I would not give your knowledge and programs away. Those of us that know you can confirm the time and money you have invested and you deserve to see a return on that investment. The service and piece of mind that you provide is priceless in my opinion. You make it look very easy but we don't see those long hours and all the headaches you went through to get to this point.

I have seen a lot of folks cut corners and as the old saying goes "Pay now or Pay later". It is always cheaper to pay now.

Just my opinion

Get-R-Wet

stevesxm

8% of 1200 is 96. i would suggest that unless this motor is doing something extremely unusual, ( and i would guess if its stock and running flat out on at least average good gas that its probably seeing egts in the 1100 to 1150 range ) that that extra hundred , if it shows up, isn't going to detrimental in any respect.

exhaust tuning was a very big part of what i did. a lot of the classes i dealt with used low compression motors with very very mild cams. every bit of power you could steal was worth killing your mother over. from this work, i can tell you that, unless the original exhaust sytem was absolutely scrap... which was , of course , possible... there were no huge and certainly no dangerlously lean exhaust system changes we ever stumbled across. i can remember doing some 400 inch firebird transam motor... box stock with factory cast iron manifolds. made 305 hp or so. egts at 1100. did nothing but unbolt the cast iron manifolds and bolt on an early set of factory manifolds with the factory dual exhaust from a much earlier varient of the car. instant 355 hp and no change in the egts that even suggested rejetting.

i believe the factory guys are good at this. i have said that before. i would expect that if we took the motor that started this discussion and bolted it to the dyno and ran it back to back with the exhausts you would see a minimal increase... 5 hp maybe ... 10 at the absolute outside. i would predict that if you then tweeked the fuel and the ignition curves on the dyno to the best of your ability you might see another 5 peak MAX and a bit more in the middle maybe... and i emphasize maybe.

for a 8000 boat that goes 60 mph to overcome that drag in a fashion that gets you another 5 mph is close to 50 hp per motor.

so... whats the cost benefit analysis here ? if the exhaust was truely the junk tiny little merc ones, then a set of gills or something along with the computer work sets you back what, 3 grand a motor ? for 10 hp peak MAYBE which might equate to an increase in performance of 1 mph ... maybe.

doesn't make any sense to me.

there was a post here about a month ago where a motor guy did a proper marine exhaust dyno comparison... 4 or 5 different sets with good repeatability... and the results were as expected. the manufacturers claims were , essentially blue sky bullsht.

there is no magic to any of this. nothing is for free. if you want more power, it comes from changing the thermodynamic properties of the motor. that comes from significantly changing the mechanical makeup. i believe that the manufacturers of aftermarket performance equipment ( msd as an example) prey upon enthusiasts that so desperately want to " believe" that they will piss away their money on almost any promise at all.

it is my opinion that the vast majority of aftermarket " one size fits all" performance "tuning" products are , for all intents and practical purposes, worthless without the necessary mechanical changes needed to make the desired power.

prove me wrong. show me the independant dyno runs of a box stock factory 502 mag mpi with the stock ecu and no correction factors, followed back to back with the " tuned" ecu. show me where the factory left 50 hp on the table because they wanted to go to lunch early that day.

Hardin Marine

I have to admit I have never put exhaust on a Firebird Trans am but I sure as hell have on a 502 MAG. So you say prove it? How about a gentlemens bet because I think talks cheap and we should both put our money where our mouth is. I have a great idea I will put my money where my mouth Is I will bet you $5000.00 I can make a 30 horsepower change with a set of lighting headers on a 502 Mag over a stock cast iron manifold change? Put the money up and I will put mine up and prove it. As long as when were done the wrong person admits they don't know anything about 502 Mags and Tubular headers Other than that we are all wasting our time on opinions. have a great day.Dustin and Mark I will split the winnings with ya.

Whipple Charged

Well said Mr. Cal Man! You know, you and I, as well as others have worked our butt's getting these cals right. Modifying knock tables, ignition and idle settings, elevation and temp settings to be better than the OE cals. We've gone through the goods and the bads, we're the ones that have taken the flack when something isn't right, or there's something odd. We trouble shoot, problem solve and continue to support all these computers, we even offer advice and help others that don't have our product our services. But donating calibrations for a minimal fee, so everyone can share all our hard work, financial investment and technical know-how? Ya, no thanks. More than willing to give advice, help a fellow boater out, but thats as far as it goes.

Thanks

Whipple Charged

I can tell you first hand, I'm not a big fan of exhaust systems. Most claim huge numbers for such low dollars when I'm selling a SC that makes 50% in most cases. But the fact is, the 93-2001 454 and 502 mag have horrible, horrible, horrible exhaust systems. They work, they flow air, they last a pretty long time, and lord knows they're not going to blow away in a wind storm! With that being said, a "tubular" long runner header such as Hardin's, Lightning and CMI all will make a noticeable difference in torque. If you couple that with the proper calibration, you will see benefits. Because every boat is different, I can't tell you what you would gain, but there is a difference. So did Mercury leave HP on the table, hell ya they did! They don't have to squeek everything out of her, they weren't dealing with emissions at the time, and were mainly looking for minimal warranty claims. Therefore, they are setup safe and conservative. They also were made cheap, they didn't put CMI headers like the 500hp EFI, because those cost at least 5 times as much. Would they benefit, yes, actually they would. OE's, and yes, I know, since I deal with them all the time, pick a power level, then achieve it the cheapest and most effective way. They want the highest profit possilbe while minimizing warranty claims. They wanted 385hp, that motor, which came from GM, made it easy. They just had to marinize it. It had nothing to do with going to lunch early, or a friday motor, its because they were able to achieve their goals with they already had been producing.

The 500hp efi was essentially the 502 mag, but different headers, valvetrain and intake manifold. It was all of 75hp different. Some was in the header, some in the cam.

Maybe the customer wants to run 91 octane, then you can run 5 deg's more spark, and those motors have no problem with that. Maybe he wants 89, then he can run 2.5degs. Fact is, Mercury has it setup for less than 87 octane so there is a margin for increase in power and efficiency. What about fueling, all of Mercury's earlier motors were setup to run 11:1-12:1 at all rpm and load points. Why? Well safe and conservative, but not always ideal. Mercury racing is the same, the 500hp efi doesn't even have altitude compensation, so, a customer in Tahoe could suffer.

I don't sale exhaust, and in fact, thats to some degree competition to me, but this is what I've seen over my few years.

Thanks

stevesxm

well... then this is easy. if you have done it, post the sheets.
if you haven't done it, then what are the claims based on ?

and the discussion is not about exhausts... if the stocks exhausts are worthless pieces of junk, then yes. you can se that increase just as i did on that pontiac motor but i THOUGHT the discussion was about exhaust gas temp increases and their potential destruction of the motor and the mythical unicorn 50 free hp ecu on a box stock motor.

its not a challenge... its a polite request. if you have taken a box stock 502 mag mpi and done nothing but prgram an ecu for it , i would like to see the uncorrected sheets.

if you want me to pay 5k to see the sheets that support your point, no thanks.

if you have them, then i will be the first to say " great work and send me two."

uncorrected , back to back data , please.

Hardin Marine

I guess in the end when the discussion turned to exhaust making only 5-10 horsepower I figured we were way off base. I'm sure You as I have way better things to do than devote anymore time to this. Some of the most knowledgeable MEFI tuners in the country have spoken and the consumer can make their decisions based on that info. As for me I'm in it for the customers best interest, we don't sell a single product we don't stand behind. As for the gentleman's bet was just to make the time justified to prove a point worth the energy invested. I figure the guys willing to put their money where their mouth are must be pretty confident in their product and work, everything else is just lip service. I gonna keep my data and my knowledge for the customers that believe in it and for those that don't I hope the reward of the $300 saved is worth every penny.

I figure at this point if customers don't want to heed manufactures warranties who am I stop them. I don't police speed laws so why police customers purchases.