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Out with the 2.5, in with the 5.7.
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joecitizennn  



Joined: 12 Sep 2005
Posts: 2093
Location: no mans land

PostPosted: Mon Oct 10, 2016 1:14 am    Post subject: Reply with quote

Found it.

http://944hybrids.forumotion.com/t1190p45-5th-gear-options-audi?highlight=audi+5th

"Mike, from my research: the swappable 0.68 5th gear is in '80-'82 Audi 5000 Diesels w/trans codes: UF, MN, BMO, WV, UW, MO, MR, AAW, AAV, AAY, AAX, AMM, & AMN.

I saw more of these boxes at either All Auto Recycling (719) 683-9600 or Jerry's Foriegn (408) 993-9711, both up in the NW somewhere."
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold
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joecitizennn  



Joined: 12 Sep 2005
Posts: 2093
Location: no mans land

PostPosted: Fri Oct 14, 2016 3:43 pm    Post subject: Reply with quote

The nagging question about putting a lt1 v8 in a 924s: Does the heavier engine ruin the handling?

No.

The cast iron block lt1 is heavier than an Ls1 which in turn is heavier than the 2.5 Porsche engine that i pulled out. It sounds bad. Pulling out an all aluminum 4 cylinder engine and replacing it with a cast iron v8 with over twice the displacement, Its got to ruin the balance of the car right? Most people seem to be of this opinion and my fears were much the same when i started this project.

Back in 2012 when i started planning, within my plans were ideas of how to beat the weight factor. My thoughts ranged from removing weight from the nose to even adding weight to the rear to bring things back in to balance. I was certain i would have to beef up the springs to handle the weight.

I have looked many times on the internet for weights of lt and ls series engines, and the web seems awash with different weights, in fact no one seems to agree on what the weight of the engines or the blocks are. I have seen statements of engine weights as high as 700+ lbs and block weights over 300 lbs for the lt1. There is some reason for the lack of consistency. The engines get weighed in endless configurations. There are iron head and aluminum head versions of the lt1, there are engines that get weighed with flywheel and clutch and there is a variety of accessory setups and emission devices that can be on the engine when its weighed. If this does not confuse things enough, people get mixed up on block weights too. There are long block, short block, and bare block weights. Someone babbles that a lt1 block is 300 lbs and a ls1 block is only 100, when they are comparing a short block weight against a bare block weight. This gets people saying in forums that the iron block is 200 pounds heavier than its aluminum sibling.


The first thing i noticed when i plunked the lt1 down into the 87 924s, was that the front end did not change in height from where it was with the 2.5. If that wasn't strange enough the car seemed to zip around corners pretty much the same. The suspension handled the weight fine and there was no understeer or oversteer "Wait, that cant be right.. this thing should be sagging and leaning into the corners with this iron behemoth under the hood.."

Despite the fact that the Lt1 definitely weighs more than the 2.5 Porsche engine, my hybrid still handles the same as my other 924 944 type cars which still have their original power plants. What gives?

The best approach to the question of motor weight is to weigh the motors you have, in the trim you have. Unfortunately i did not do this when the lt1 was out of the car, and i am not about to pull an engine just to weigh it. This leaves me with task of finding a breakdown of component weight or at least finding an engine trimmed just like mine that was accurately weighed.

I swiped this spreadsheet off ls1 tech.com which gives the weights of the individual parts and the weights of the engines as a whole. The information is very interesting.




First off, according to the spreadsheet the bare blocks between the lt1 and the ls1 weigh in only at 58 lbs difference. That is about the weight of 7 to 8 gallons of fuel in your tank. I have found multiple sources that state that a naked sbc 350 iron block is around 150 lbs, with the exception of "bowtie" blocks which weigh between 180 to 190 lbs, so this seems accurate. Interestingly, adding an iron block to an LS motor adds 100 lbs of weight, putting iron Ls blocks in the 200 lb range.

Secondly, the aluminum head lt1 in basic EFI trim weighs in at only around 382 lbs while the iron head version is 422 lbs. This is not including the engine accessories or accessory bracket, or flywheel etc. Compare that with the 355 lb all aluminum ls1 and you are looking at only around 27 lbs difference, or 67 lbs difference for an lt1 with iron heads. When most internet posters rattle off weight differences between the Lt1 and the Ls1, the claim is from over 100 lbs to several hundred pounds difference. Under close examination this does not appear to be accurate.


If my research is correct, the bare 2.5 944 block weighs around 65 lbs, but block weight alone is not a good comparison since the 944 has entirely different kinds of bolt-ons than a small block Chevrolet. The 1983 944N/A motor supposedly weighs 368 lbs, with flywheel, NOT including the power steering pump, clutch, pressure plate or bellhousing. I don't know if this weight figure includes the alternator or not, but for the sake of the Porsche motor i will assume that it does. So if you subtract a 15 lb flywheel and a 13 lb alternator, you get a motor weighing 340 lbs.

If you round up the Chevy v8 weights you get:
Basic lt1 390 lbs.
Basic ls1 360 lbs.
Basic 2.5na 340 lbs.
(Remember that these figures don't include manifolds, flywheels, accessories, brackets, engine covers, emissions devices or fluids.)

If this is true, and all the mentioned weights are accurate, it explains why my car does not seem adversely affected by the weight of the Lt1. I am not running the Chevrolet accessory bracket, smog pump/emissions stuff, idlers, ac, or GM power-steering pump. I just have the 944 ps pump and alternator bolted directly to the belly with Porsche turnbuckle tensioners. Theoretically, i have only added about 50 lbs to the car with the engine. My complete a/c delete deducts some of that weight, as well as removal of a few other things up front.

If you look on 944transformations.com, you will find that they say a ls1 adds 50 lbs, and an lt1 adds 200 lbs to the 944! That is a tremendous figure and it makes me wonder where they got it. Did they weigh a lt1 freshly plucked from a impala ss with iron heads, still wearing all accessories, flywheel, clutch and pressureplate? Are they using a figure gathered from a factory gm manual or a parts house?

I don't know the actual figures on my setup until i pull the engine as it is, and weigh it against the 2.5 that i have sitting in the shed. I plan to do this someday and will post the results here when i do. Until then i can only speculate. The car handles pretty much like a 951 or a 944. I noticed more of a difference in handling going from 245 tires on 16 inch rims to 285 tires on 18 inch rims in my 951. That took some getting used to.

While the weight figures may or may not be spot on, its food for thought. If i only added 50 lbs to the car, what did it actually do? A fill-up at the gas station can change the weight in the rear by more than 100 lbs. To a competitive race car 50 lbs is a lot, but this is not a race car. I do not plan to rip out my seats, gut my doors, install lexan, change the whole body to fiberglass and drill holes in anything solid. Loosing the ac and radio was enough.

My personal experience says that the lt1 ruining the handling and balance is a myth, or at least an exaggerated theory. A big block with iron heads or a cummins 24 valve would probably screw things up to where you needed new springs, some fiberglass panels and counterweights but the lt1 seems to be within the capacities of the 944/924s suspension.

Just for fun, here are some engine weight claims I snagged off Rennlist.
968-385 lbs
944 S2- 380 lbs
951- 404 lbs
944NA- 355 lbs
924 Carrera GT- 385 lbs (includes intercooler and turbo)
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold
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nickthompson  



Joined: 26 Mar 2013
Posts: 840
Location: Central Georgia

PostPosted: Fri Oct 14, 2016 6:59 pm    Post subject: Reply with quote

The 924S and 944 have a slight rear weight bias anyway. You probably brought it closer to 50/50.
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11332
Location: PacNW

PostPosted: Sat Oct 15, 2016 2:41 am    Post subject: Reply with quote

Long time no see! Glad you're not submerged.

Great post Joe.
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  • Shaggy (1980 931) - Got Boost?
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joecitizennn  



Joined: 12 Sep 2005
Posts: 2093
Location: no mans land

PostPosted: Sun Oct 30, 2016 2:51 pm    Post subject: Reply with quote

Just in time for Halloween. Pumpkin orange rollers made here in the states by Harland Sharp.






Due to concerns about my 3/8 rocker studs withstanding the vigor of the camshaft and heavy valve springs, I upgraded to 7/16. These are excellent rockers. Fit and finish are superb, and while they completely fill the LT1 valve covers they don't hit anything. My old rockers were a little noisy while these whisper like a sewing machine.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold
Back to top
View user's profile Send private message
v8carreragts  



Joined: 05 Sep 2003
Posts: 651
Location: Tucson, AZ

PostPosted: Mon Nov 07, 2016 5:47 am    Post subject: Reply with quote

I weighed my 302 before i installed it. From the carb to the flywheel it is 434 lbs. With FI (modified LT1 intake and HEI) it weighs 430 lbs.

This does not include the steel scattershield or the clutch and adapter plate.

I have a OEM 4 bolt block, aluminum aftermarket heads, roller cam and rockers, mini starter, aluminum water pump, full length headers, SFI 19# steel flywheel, SFI 8" balancern forged crank, 4340 steel rods, lightweight racing pistons, lightweight tool steel piston pins. The difference between the carb and FI is the aluminum manifold and carb VS the FI manifold and throttle body.
_________________
84 944--924 Carrera GTS clone w/520HP Chevy 302 V8--RUNNING!
2013 AUDI Q5
2013 Dodge Charger R/T AWD HEMI
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joecitizennn  



Joined: 12 Sep 2005
Posts: 2093
Location: no mans land

PostPosted: Mon Nov 07, 2016 9:12 am    Post subject: Reply with quote

So you have a 430 lb engine with lt1 intake.
-15 lb flywheel
-14 lb altenator
-10 lb p/s pump
-12 lb long tube header each side. 24lb total
-?? Accessory bracket??

=367 lbs.

27 lbs heavier than a naked 944 engine. Sound right?

Not bad for over 500 horsepower with normal aspiration.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold
Back to top
View user's profile Send private message
v8carreragts  



Joined: 05 Sep 2003
Posts: 651
Location: Tucson, AZ

PostPosted: Mon Nov 07, 2016 10:29 am    Post subject: Reply with quote

It's a gen 1 sbc. And your number is about right And with the non opening head lights and GTS bumper my car is lighter in front than a stock 944.
_________________
84 944--924 Carrera GTS clone w/520HP Chevy 302 V8--RUNNING!
2013 AUDI Q5
2013 Dodge Charger R/T AWD HEMI
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joecitizennn  



Joined: 12 Sep 2005
Posts: 2093
Location: no mans land

PostPosted: Thu Nov 17, 2016 12:59 pm    Post subject: Reply with quote



This is probably the best thing i have put in this car besides the LT1. This gauge is to custom tuning what a boost gauge is to turbocharging. The digital readout is so accurate you can see the fluxuation of the a/f ratio after the system goes to closed loop. I am contemplating running two of these with a wide band 02 in each bank.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold
Back to top
View user's profile Send private message
joecitizennn  



Joined: 12 Sep 2005
Posts: 2093
Location: no mans land

PostPosted: Wed Nov 30, 2016 2:24 pm    Post subject: Reply with quote

The following is a video of the car in its current state of tune.

https://www.youtube.com/watch?v=31NxfPgKIcg



Horsepower is a little over 440 and weight is about 2750. Fuel economy seems to vary greatly depending of driving style, from 23mpg down to 16 if you drive like a peckerwood. The car is very well planted with 245 potenzas and a lsd gearbox, but it can still break both tires free in 3rd and 4th with a hard goose depending on pavement texture. I do worry about destruction of driveline componets, specifically ring and pinion and cv joints. As a result i try to be very careful on how i load the driveline with torque, especially during shifts. I had initially thought about installing a garrett turbo, but the result would necessitate the upgrade of nearly everything on the driveline and suspension as well as more engine and tuning mods. I am happy with what i have now, however i see a bigger brake upgrade in the future as well as some suspension stiffening in the rear.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold
Back to top
View user's profile Send private message
nickthompson  



Joined: 26 Mar 2013
Posts: 840
Location: Central Georgia

PostPosted: Thu Dec 01, 2016 1:18 am    Post subject: Reply with quote

The roads around there suck.
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81 924 N/A 1.8t swap in progress.
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joecitizennn  



Joined: 12 Sep 2005
Posts: 2093
Location: no mans land

PostPosted: Mon Jan 30, 2017 1:09 pm    Post subject: Reply with quote

nickthompson wrote:
The roads around there suck.


Courtesy of bureaucratic corruption. The car was lowered substantially at one point but i had to raise it up to prevent occasional bottoming.
_________________
87 924s
88 924SE gone
447 hp cgt clone
87 924S gone
84 944 sold
83 944 sold
89 turbo S LSD, ABS etc
86 951 white rocket
85 944 sport everything.
84 944 sold.
87 944 sold
Back to top
View user's profile Send private message
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