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View Full Version : Horsepower Rating for LT-1 Corvette Motor


BarefootWt
10-08-2008, 11:31 PM
do the HP ratings differ in the years 94 - 97 if the ProStar 190 comes with an LT-1? I hear between 320 and 350 and am thinking they may have increased the HP year after year?

duckguy
10-08-2008, 11:35 PM
I was told my 96 190 was 318, It was a great motor.

Andyg
10-09-2008, 01:18 AM
I know the 97 PS190 I had with the LT-1 had 328 HP.

Jerseydave
10-09-2008, 04:50 AM
My '94 had 310HP, they bumped it up to 328HP a year or two later I think.

captain planet
10-09-2008, 09:42 AM
If I recall correctly, the 97 LT-1 was 330. And I say this because a friend of a friend had a 98 Duvall with the LT-1 and he had 330 hp. I have a 98 Anniversary with the LT-1 and it is 350 hp (they modified the anniversary boat engine). It was a running joke I had 20 more hp than he did. My guess is the 97 was also 330.

mbpd312
10-09-2008, 10:28 AM
correct on the 97, it has 327HP.. everyone calls it 330HP. from the years 95-97 every year had a slight increase. I know the 96 LT1 has 319HP. I cannot remember what the 95 offered

Andyg
10-09-2008, 11:35 AM
The 1998 was 340 HP.

russlars
10-09-2008, 12:06 PM
The 1998 was 340 HP.
Can someone interpret the "E" "W" and "T" ratings on wake, etc. for me?

east tx skier
10-09-2008, 02:24 PM
Here you go ... from 1998.

russlars
10-09-2008, 02:41 PM
Here you go ... from 1998.
Thanks East TX Skier. I'm wondering if these same numbers would apply to my '99 205? I believe that the hull is the same for the '98 and '99 205 isn't it?

sethro
10-09-2008, 09:27 PM
I checked the 94-97 Waterski Mag boat buyer's guide. They have no listing for HP for the LT1 after 1994.

1994-rated at 310hp
1995-says an increase of 6-8hp and 4% better fuel economy, but no number
1996-mentions increase of power for LT1 with new cam and ECM calibration, but no number
1997-no mention power increase for LT1, and still no number

east tx skier
10-09-2008, 09:52 PM
Thanks East TX Skier. I'm wondering if these same numbers would apply to my '99 205? I believe that the hull is the same for the '98 and '99 205 isn't it?

The weight might have changed a bit in 99, but the hull is the same. HP for 99 on the base engine was bumped to 310 hp from 308 hp.

coz
10-09-2008, 10:08 PM
The 1998 was 340 HP.

Is this WS mag? It's been proved to be wrong :rolleyes: I have my 1998 manual in hand and the base was the 5.7 Vortec MX Plus 298hp (300hp) and the Lt-1 was 328hp

My manual includes the 190, 205, x-star and the sammy series

My 300hp MX Plus
http://farm3.static.flickr.com/2266/2093611224_c8605d0a76_b.jpg

east tx skier
10-09-2008, 10:19 PM
Indmar doesn't post HP specs. So I don't know that MC is any more reliable than WSM on that subject. Just my opinion though. But putting it on the dyno is the only way to be 100% sure.

From what I can recall about 98, the Sportstar had a 260 hp 5.0. The Vortec TBI was 308 hp. The LT1 was 328 and the LT1 Anniversary had a different cam and got 350.

cbryan70
10-09-2008, 10:23 PM
I believe if mastercraft advertises it that it has to be within a certain percentage of the HP? That is how it is in outboards if it is a good "star" rating.

coz
10-09-2008, 10:40 PM
I believe if mastercraft advertises it that it has to be within a certain percentage of the HP? That is how it is in outboards if it is a good "star" rating.

I'm gonna stick with the builder specs in the manual because they can't advertise something in a manual and have another engine instead :confused: when I get parts it's for a 1998 300hp MX plus and that's what the computers say too (skidim, isspro) for that year PS 205 :D

east tx skier
10-10-2008, 12:03 AM
I'm gonna stick with the builder specs in the manual because they can't advertise something in a manual and have another engine instead :confused: when I get parts it's for a 1998 300hp MX plus and that's what the computers say too (skidim, isspro) for that year PS 205 :D

Okay, but if you want to go by the 98 manual (http://www.mastercraft.com/files/manuals/1998_OwnersManual-PS190-PS205-XStar-SammyDuvall.pdf), it's 298 hp.

zippo190
10-14-2008, 03:38 PM
98 Lti Was 340 Horspower And With The Powerslot It Was A Beast I Pulled 2 Deep Water Barefooters Out With It And It Was Not Even Slowed Down From The Pull Of The Barefooters

ProTour X9
10-14-2008, 04:57 PM
LT-1 great engine........ ours was 319hp in 1994 because the dealer put a chip in it.

BarefootWt
10-19-2008, 12:57 PM
Thank you all this was helpful.

JimN
10-19-2008, 01:11 PM
LT-1 great engine........ ours was 319hp in 1994 because the dealer put a chip in it.

There is no chip that can be installed. The program can be altered, but unless that recal program came from Indmar or MC, it instantly voided the warranty (which is a moot point 14 years later). The marine ECM is a sealed unit and can't be opened without damaging the cover. Also, I thought 319 HP was standard for the original LT-1 and any small increase over the original spec shouldn't be noticeable unless more torque came along for the ride, which is probably what made the difference.

ProTour X9
10-19-2008, 01:23 PM
Thats just what the dealer said....!

JimN
10-19-2008, 02:01 PM
Thats just what the dealer said....!

Did they say what the difference would be?

Call me a stickler for detail or whatever, but when someone tells me that they did something, I want all of the info to be as accurate as possible. When I would do a recal, I just told the customers that it was a re-program and that no parts were needed. "Put a chip in it" and "recalibrate" serve the same purpose but one way makes it sound like it's possible for the user to reverse it and the other doesn't.

As long as it ran great and you enjoy it without problems, it's just a technicality.

ProTour X9
10-19-2008, 05:19 PM
I was one year old when my father bought the boat 13 wonderful years later when I became interested in it and before he sold it, for some reason (loss of memory, senile...) he said they put a chip in it. He may have said they tweaked it or something, I can't even recall, it was a 94 built in 93.

The boat would jump out of the water ok, end of story.

YooperScott
10-20-2008, 10:11 AM
From what I can recall about 98, the Sportstar had a 260 hp 5.0. The Vortec TBI was 308 hp. The LT1 was 328 and the LT1 Anniversary had a different cam and got 350.

So Indmar actually changed the cam? I did not think they did that? Funny the LT1 changed horsepower in the boats but not in the cars? '93 and up Z28's were 275 until '96 when they went to a dual cat setup and rated them at 285. '92 and up vette's were all 300 hp. The only difference in horsepower was when the LT4's came out. There were some slight changes in cam specs during those years but nothing one could argue added more than a couple hp, if that. At any rate it seems to me unless Indmar did actually swap internal parts the only real horsepower differences could have been some better programming. I could see gaining 5-10 hp but more than that is probably a stretch. The boats have a different computer than the cars right? That's too bad or else I would be messing with mine because there is a program called LT1 edit that worked on the cars.

My question on the horsepower is did all the LT1's come with the same prop (other than slot, no slot)? If so was there any difference in speed (RPM's) that they went (say '95 - '97 when the hull was the same)? If not then I bet there really was not a difference in horsepower.

That is just my 2 cents from someone whom used to do lots of modifying and racing of LT1 powered cars.

Scott
'95 LT1 Prostar 190

JimN
10-20-2008, 10:21 AM
So Indmar actually changed the cam? I did not think they did that? Funny the LT1 changed horsepower in the boats but not in the cars? '93 and up Z28's were 275 until '96 when they went to a dual cat setup and rated them at 285. '92 and up vette's were all 300 hp. The only difference in horsepower was when the LT4's came out. There were some slight changes in cam specs during those years but nothing one could argue added more than a couple hp, if that. At any rate it seems to me unless Indmar did actually swap internal parts the only real horsepower differences could have been some better programming. I could see gaining 5-10 hp but more than that is probably a stretch. The boats have a different computer than the cars right? That's too bad or else I would be messing with mine because there is a program called LT1 edit that worked on the cars.

My question on the horsepower is did all the LT1's come with the same prop (other than slot, no slot)? If so was there any difference in speed (RPM's) that they went (say '95 - '97 when the hull was the same)? If not then I bet there really was not a difference in horsepower.

That is just my 2 cents from someone whom used to do lots of modifying and racing of LT1 powered cars.

Scott
'95 LT1 Prostar 190

You can gain more HP when you don't have to hit EPA/CARB/CAFE emissions numbers and the cars are run pretty lean. The timing advance is different, the fuel mapping is different, the boats were run open loop until recently and the HP rating can 't be far off of what's stated or it's false advertising.

YooperScott
10-20-2008, 10:39 AM
All true but they were always open loop, etc, etc so either the programming was horrible to start and they made it much better (still doubt there was that much "programming" on the table or well .......

Simple fact is Indmar changed parts (did not think they did that) or else most likely some of this was wishful thinking.

Again with the same prop and hull you could compare speed numbers and get some real world data to help confirm or deny horsepower differences.

Scott
'95 LT1 Prostar 190

JimN
10-20-2008, 11:04 AM
"so either the programming was horrible to start and they made it much better"

I have to think they were being conservative with the program because that was probably the first ski boat with an EFI engine and after more extensive testing, they found what survived and what didn't. Shipping a boat with a motor that blows up isn't a good plan (like Malibu when they first came out with the LS-1) and since people don't always care for things impeccably, they may have wanted it to be as durable as possible.

YooperScott
10-20-2008, 12:11 PM
So my question then is, was the PCM the same (obviously not the program itself but the computer) and if so what is it from? Anyone know? If one could get software to program it, then copy the '98 program into it and gain power. My '95 does have some stumbles that I think are program related that would be nice to fix. More horsepower would be a nice side benefit.

Scott
'95 LT1 Prostar 190