Jump to content

 

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Sign in to follow this  
Kevin 89MC

question about EFI vs. carb for course skiing

Recommended Posts

Kevin 89MC

Long time lurker here, but I don't post much.  
My main question: is there much of a difference in how they feel to a slalom skier?
Quick background and reason for the question: On a good day I get deep into 28 off or a few at 32 off.  Been at 34 mph but spending more time at 32 mph recently.  So not a shortline skier by any means, but always trying to improve.  Currently I have a 1989 Prostar, 351 w/ GT40 heads, 1:1 trans, classic PP with slalom switch.  A very good ski boat, but looking to upgrade for more space. I ski a lot behind a friend's 1996 Nautique 176, same engine and reduction trans, classic PP w/switch.  My absolute favorite boat to ski behind, but even smaller than mine.  My wife's cousin has a 1999 Response LX, no speed control, just free ski.  I have a friend with a 2000 Response LX with classic PP that I get in the course once a year. Great boats to ski behind as well.  
I'm mainly looking at 1999+ Response LX (also considering PS 197's).  They RLX has got everything I need and nothing I don't and are starting to become affordable.  I found a good deal on one on onlyinboards, at Tommy's of Detroit, and they have another one there as well.  The odd thing is one of them has EFI and the other one has a carb.  I was pretty sure Malibu had gone EFI by then in the Responses, but maybe not.  I believe the Echelons may have had carbs, but this one is a Response, as it has a trunk (decals were replaced).  I don't mind having a carb from a maintenance standpoint, but I wonder if the EFI would be better from a course skiing perspective, as far as engine/throttle response.  No matter what boat I get I will be getting PP SG, and maybe Zbox as I struggle a bit when skiing tournaments as that is the only time I see Zero Off.  I plan to post this on themalibucrew.com to see what they think as well.  My guess is PP classic would be fine with carbs, but thinking SG is maybe better suited to EFI?
Appreciate any thoughts.  
Thanks,
Kevin

Share this post


Link to post
Share on other sites
solorex

Caveat: I only free ski, I don't ski the course, but I do ski a lot.  I have honestly never really noticed a difference skiing behind a carb'd or EFI boat.  My boat's over 20yrs old, carb'd and it pulls a skier out and has excellent throttle response.  Everyone grins ear to ear whenever they ski my tantrum (sportster hull).  Wake is so tiny.  For a ski tug, weight and hull design matter the rest is just creature comforts... :)

Share this post


Link to post
Share on other sites
Sixball

In 99 you could get ether Carb or EFI.  I ski both a Carbed SS lxi and R lxi EFI  and a CC 196 EFI. I have never felt a difference between carb and Inj. other then maybe the start. But that is only the carb boat could use a carb rebuild. Once up its all the same to me. I do like cruse control just for the driver not needing to be watching speed all the time. And even then a good driver its not a factor to me.   I think the choice for carb and EFI my have only been on the standard engine. I think the monsoon was a EFI in 99 .

 

Share this post


Link to post
Share on other sites
Eagleboy99

Monsoon was most def. EFI. Got one.

Share this post


Link to post
Share on other sites
Woodski

@Kevin 89MC - In the course or out skiing behind an EFI or carb fed boat you won't notice a difference assuming properly tuned.  Does not matter what line length either FWIW and one step more, barefooting behind a carby is also fine.  The area you will notice is cold starts, EFI has a clear advantage in many cases, many carbs need a quick throttle prime to fire quickly and maybe the warm up is less smooth.  Once warmed up they are fine.  PP can sometimes end up throttling at the secondary tip in point so that may induce some surging, there is a suggested correction for that if it happens.  My friends EFI boat (Malibu) has a pronounced throttle tip in hesitation so I suggest you don't make any assumptions without testing your intended purchase.  You can / will make a much more significant change in pull / feel by speed control parameter adjustments, in the case of PP the Kx, Px values will alter the pull much more than how (carb / EFI) the fuel is delivered.

BTW - I and probably many on this site think you will be really happy with an RLX, great slalom wakes.  Also, seems like the latest SG software update closes the gap between PP and ZO, a thread on the other site you posted to peruse at your leisure (well for the next few months anyway...)

Share this post


Link to post
Share on other sites
barefootpaul

Monsoon was efi in 99. I had it in my 99 response. Owned it for 12 years and ran perfect the whole time. Just sold it this summer and I am still sad.

There may have been a base engine that was a carb, but get the monsoon.

Share this post


Link to post
Share on other sites
Eagleboy99

Pretty sure the Merc Black Scorpion was an option too.  I think the base engine was the 305/310 HP carb; have to find my 99 brochure.

Share this post


Link to post
Share on other sites
Woodski

Resources guide on this site should have the engine option info.  Agree with @Eagleboy99 on my recollection of available units, Merc's and Indmar.

And reading back over your post, PP SG should work fine with a carb and probably be your better option.  PP customer service is outstanding, I would contact them and get their expert insight on your goals for the system.

Just for some additional insight, I have changed my power output, prop and some hull changes a few times using the same PP system and it does not really care, simply do a relatively simple baseline recalibration if needed and it is spot on.

Edited by Woodski

Share this post


Link to post
Share on other sites
85 Barefoot

You can (and should) run stargazer on a carbed or EFI boat for a few reasons.  One, it is WAY simpler, but from a performance standpoint, unless you're running magnets with classic (doubtful), you get ABT (all buoy timing) with SG.  If you did run a carbed boat, that was down on power compared to an EFI (which it will be), you can see your buoy times.  SG will easily allow you to adjust parameters so that SG "keeps the carby up".  In other words, you cna trick the carb into "better" course times.  Can you get 16.95 with classic and a carb, sure, but the parameter adjustment (better than kx px etc) with stargazer is far easier and superior.  I ran a 99 ski nautique carb for 2 years w SG.  Great boat.  Now run a 196 (EFI) with SG.  Hard to tell any difference in the course.  All things being equal, however, get the EFI if its remotely close, but you can run stargazer in a carb no problem which I would highly recommend.

Share this post


Link to post
Share on other sites
Slayer

^^^^^This, exactly.  

 

 

Share this post


Link to post
Share on other sites
Nitrousbird

If looking at a carb boat, I would lowball the hell out of them.  A lot of people will not even consider the carb motor, so that automatically makes it a harder sale.  

Share this post


Link to post
Share on other sites
85 Barefoot
On 11/8/2019 at 8:24 PM, Nitrousbird said:

If looking at a carb boat, I would lowball the hell out of them.  A lot of people will not even consider the carb motor, so that automatically makes it a harder sale.  

I bought a carby nautique 2 years ago.  Put 200 hours on it and sold it for a profit.  I had plenty of people who WANTED the carb.  It's come full circle.  Point is, carbs are no longer the deal killers they used to be given, especially in the nautique case, electronics for the GT40 are apparently harder to come by.  That said, I'd prefer EFI in a 350.

Share this post


Link to post
Share on other sites
MadMan
8 minutes ago, 85 Barefoot said:

I bought a carby nautique 2 years ago.  Put 200 hours on it and sold it for a profit.  I had plenty of people who WANTED the carb.  It's come full circle.  Point is, carbs are no longer the deal killers they used to be given, especially in the nautique case, electronics for the GT40 are apparently harder to come by.  That said, I'd prefer EFI in a 350.

My '00 Malibu came with "Fuel Injection" decals on the side windows, like it was some sort of status symbol.  I remove them (along with others) the day I got the boat.

Share this post


Link to post
Share on other sites
Woodski

@85 Barefoot - curious, why do you say a carb will be down on power compared to EFI?  The 4bbl. Weber on your typical Merc or a Holley 4160 are 750 cfm, plenty of fuel / airflow for 400 hp in reality.  PP simply 'tells' the throttle arm more or less to maintain either a speed or RPM value so it does not care how the fuel is dispersed.

Share this post


Link to post
Share on other sites
85 Barefoot
55 minutes ago, Woodski said:

@85 Barefoot - curious, why do you say a carb will be down on power compared to EFI?  The 4bbl. Weber on your typical Merc or a Holley 4160 are 750 cfm, plenty of fuel / airflow for 400 hp in reality.  PP simply 'tells' the throttle arm more or less to maintain either a speed or RPM value so it does not care how the fuel is dispersed.

My carby was 260 hp.  Once the GT40 was FI was 310 (as I recall).  The 350s were as I recall, 310 hp, and monsoons were 320 or 325.  When you're talking about fine power reactions in the hundredths of a second, I would think (because we did) have some more ppass parameter input on my carb as compared to EFI.  In other words, my old carbed 351 seemed a softer pull than my current EFI 350, despite both using stargazer, and both getting 16.92-16.98.  Was it minor, absolutely.  I'm just saying upgrading the carb to stargazer is not wasted at all, it can in fact help "dial it in".  As I recall, my carb required a hot baseline to get good times.  Was that because throttle input "given" by the system in the course was a little too little to keep up, expecting it was in an EFI?  That was my theory.  Was a great skiing boat though and I wouldn't hesitate to have another, just prefer EFI for its simplicity, including wife's ability to turn key.

Edited by 85 Barefoot

Share this post


Link to post
Share on other sites
Woodski

@85 Barefoot - I can see the logic behind your conclusion, makes sense.  The real 'culprit' for improved HP is not the fueling method, it is the cylinder head flow in both the GT-40 and GM SBC engines.  The GM Vortec head was the 265 to 310 hp bump as was the GT-40 cylinder head the bump from 240 to over 300 as you note.  It just so happens that EFI rolled in pretty much simultaneously with those changes and thus kind of masked the real contributor.  There is the response time consideration when comparing EFI to carb although that may boil down to a simple throttle arm ratio.  Many EFI systems actually throttle up to 70% of WOT by 30-40% of actual throttle travel which of course could be done with a carb if desired.  In your case, PP could be the processor that does that.

Share this post


Link to post
Share on other sites
85 Barefoot
1 hour ago, Woodski said:

@85 Barefoot - I can see the logic behind your conclusion, makes sense.  The real 'culprit' for improved HP is not the fueling method, it is the cylinder head flow in both the GT-40 and GM SBC engines.  The GM Vortec head was the 265 to 310 hp bump as was the GT-40 cylinder head the bump from 240 to over 300 as you note.  It just so happens that EFI rolled in pretty much simultaneously with those changes and thus kind of masked the real contributor.  There is the response time consideration when comparing EFI to carb although that may boil down to a simple throttle arm ratio.  Many EFI systems actually throttle up to 70% of WOT by 30-40% of actual throttle travel which of course could be done with a carb if desired.  In your case, PP could be the processor that does that.

I hear you.  Makes sense.  May just be that the "anticipated" RPM response from ppass calibrations "expect" a larger (or faster)  rpm response from a particular servo movement.  My carby skied great, nice and soft, but softer than EFI, in my opinion.  Maybe it was just the HP difference.  Same OP posted the same on ball of spray and got similar response as to mine.  I guess my overall point is to OP, he is absolutely better served w stargazer in EITHER carb or EFI.

Share this post


Link to post
Share on other sites
MadMan
21 hours ago, Woodski said:

@85 Barefoot - curious, why do you say a carb will be down on power compared to EFI?  The 4bbl. Weber on your typical Merc or a Holley 4160 are 750 cfm, plenty of fuel / airflow for 400 hp in reality.  PP simply 'tells' the throttle arm more or less to maintain either a speed or RPM value so it does not care how the fuel is dispersed.

Don't know about Indmar, but Mercruiser spec'd their MPI engines with more horsepower too.  I think it was all marketing, a reason to charge more. 

Share this post


Link to post
Share on other sites
MadMan
2 hours ago, Woodski said:

@85 Barefoot - I can see the logic behind your conclusion, makes sense.  The real 'culprit' for improved HP is not the fueling method, it is the cylinder head flow in both the GT-40 and GM SBC engines.  The GM Vortec head was the 265 to 310 hp bump as was the GT-40 cylinder head the bump from 240 to over 300 as you note.  It just so happens that EFI rolled in pretty much simultaneously with those changes and thus kind of masked the real contributor.  There is the response time consideration when comparing EFI to carb although that may boil down to a simple throttle arm ratio.  Many EFI systems actually throttle up to 70% of WOT by 30-40% of actual throttle travel which of course could be done with a carb if desired.  In your case, PP could be the processor that does that.

Perfect Pass has a couple of calibration adjustments that allow you to vary how often and how much it changes the throttle position.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...