|
|
Register To Post |
| grind4it | 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Guru
 
|
I am in the middle of a 1985 C4 build. We are upgrading the engine from the L98 to a LS1 that we hope to get around 400+ to the rear wheels.The transmission is the 4L60E with a 3000 stall torque converter.
My question is: What other modification do I need to consider (U-joints, gears, etc.)? Everything from the 4L60E back is totally stock and I would like to avoid breaking parts and pieces. Thanks, Mark Attach file:  Pulling.jpg (122.13 KB) |
||
Posted on: 2009/2/10 17:24
|
|||
 Transfer
|
 
|
||
| CentralCoaster | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
 
|
That automatic you're pulling out of there tells me you have the Dana 36 rear end.
The automatic will hit it much softer than a manual, but most with 400rwhp would upgrade to a Dana 44 rear and batwing. This also requires a shorter driveshaft and C-beam, assuming you don't need to modify that stuff already. Everything else back there is the same for D36 vs D44. The used D44's with 3.07s cost less, and it's a good ratio for the 4L60e, but it begs a few questions. What are you using the car for? Drag racing? Drag radials? What rpm do you plan on shifting at? Is gas mileage and freeway driving a consideration? |
||
Posted on: 2009/2/10 22:22
|
|||
|
_________________
1985 Z51, ZF6 |
|||
|
Transfer
|
|
||
| BrianCunningham | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
 
|
ditto
|
||
Posted on: 2009/2/10 22:35
|
|||
|
_________________
Polo Green 95 LT1 6-spd http://mysite.verizon.net/vzevcp74/ 383 LT1/Vortech Supercharger/AFR heads/Rod end suspension/Penske-Hardbar dual rate coilovers/Wilwood 6pot brakes NCCC Governor: http://BayStateCorvetteClub.com |
|||
|
Transfer
|
|
||
| Danspeed1 | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Elite Guru
 
|
I would have to agree with Central, but I would not discount the Dana 44 with the 3.42's. I had the 3.42's in my 89 and loved'um. They will work very well with the power band of the LS1. The GTO for example has the same powertrain and sports the 3.42s. I have 3.42's in my SS right now, and if they didn't wine like a bitch I would love them too. This is the only site I've been on where the general consensus is to always go 3.07 or less.
Just my $0.02, DG |
||
Posted on: 2009/2/10 22:51
|
|||
|
_________________
1971 Chevelle SS (The Original) 1972 Chevelle SS 454 1995 Corvette Convertible 1996 Ford Explorer 2009 Cadillac CTS-v |
|||
|
Transfer
|
|
||
| grind4it | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Guru
|
Quote:
Thanks, This is a play car that will never see the track or strip. I will have the car tuned when complete and plan on having the shift points as close to "blowup" as possible. The action will start from a 35 mph or a 75 mph. I do not care about the MPG.I am unsure of the tires at this point but am sure they will be street tires...more than likly Z rated. Thanks again. |
||
Posted on: 2009/2/10 22:52
|
|||
|
Transfer
|
|
||
| grind4it | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Guru
|
Quote:
Thanks DanSpeed. Do you think the factory gears and other components will handle the 400+ RWHP? I have no issues with the factory setup I am just trying to understand if they will standup to the abuse I have planned. |
||
Posted on: 2009/2/10 22:55
|
|||
|
Transfer
|
|
||
| CentralCoaster | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
Well, the shift points will be a little past the HP peak then if it's save to run it there. There's no point to rev beyond that, because only upshifting will make more power.
Since you're not launching the car with sticky tires or a manual, I would be tempted to see if the D36 can hold up, but the 2.59 ratio won't impress you any. So it sounds to me like you should go for the shortest gear that doesn't completely ruin your driveability. |
||
Posted on: 2009/2/10 22:58
|
|||
|
_________________
1985 Z51, ZF6 |
|||
|
Transfer
|
|
||
| CentralCoaster | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
The D44 has a 8 1/2" ring gear vs. 7-9/16" for the D36.
Pinion is about the same though. |
||
Posted on: 2009/2/10 23:03
|
|||
|
_________________
1985 Z51, ZF6 |
|||
|
Transfer
|
|
||
| grind4it | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Guru
|
Quote:
Once again, Thanks for your help. |
||
Posted on: 2009/2/11 1:25
|
|||
|
Transfer
|
|
||
| dan0617 | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
400 rwhp on street tires, no track use? I'd keep the D36. I would go with 3.07's if staying with the D36 because the 3.54's and 3.73's are more likely to break since the ring gears are thin. I honestly doubt, with your setup and intended uses, that you will break the D36. I've talked to many that have used them much harder than you intend to with no problems. I myself have launched on motor (which was 320 rwhp), then quickly hit the 175 shot, with no problems yet, and that is with drag radials. Done it a few times at the track and many times on the street. No tire spin and no breakage.
|
||
Posted on: 2009/2/11 1:51
|
|||
|
_________________
´89 Vert, 383, 230/236 cam, AFR 195's, LT Headers, HSR intake, 2800 stall, Zex 200 shot, ET Street Radials, tune by me. Runs were with D36 3.07's. On spray, 10.55 @ 132.78, 1.55 60 ft. On motor, 12.08 @ 113.15, 1.66 60 ft. |
|||
|
Transfer
|
|
||
| grind4it | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Guru
|
Quote:
Dan, Thanks. This is the kind of responce I was fishing for. |
||
Posted on: 2009/2/11 1:59
|
|||
|
Transfer
|
|
||
| Danspeed1 | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Elite Guru
|
I would keep the Dana 36 too so long as it has the optimal gear ratio you are looking for. But if you decide to change gears, I would obviously upgrade to the Dana 44. As long as you aren't launching the car at 5K on drag slicks, I see no reason why the Dana 44 wouldn't hold up just fine, launch after launch. I have seen threads, (not necessarily on here) where guys have broken D36's but I don't know what they were doing when it happened.
Dan |
||
Posted on: 2009/2/11 4:29
|
|||
|
_________________
1971 Chevelle SS (The Original) 1972 Chevelle SS 454 1995 Corvette Convertible 1996 Ford Explorer 2009 Cadillac CTS-v |
|||
|
Transfer
|
|
||
| Danspeed1 | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Elite Guru
|
Quote:
I am pretty sure you can purchase high strength gears. I don't know if you would break 3.42s any easier then 3.07's especially on cold pavement using street tires. More likely the tires will break free before that happens. But as I mentioned, why would you upgrade the D36 when you can just find a D44 and have it all? DG |
||
Posted on: 2009/2/11 4:34
|
|||
|
_________________
1971 Chevelle SS (The Original) 1972 Chevelle SS 454 1995 Corvette Convertible 1996 Ford Explorer 2009 Cadillac CTS-v |
|||
|
Transfer
|
|
||
| CentralCoaster | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
For what its worth, the dana 44 from 85-88 came with 3.07s, from 89-96 it came with 3.45s.
Aftermarket ratios available that you might consider are 3.08, 3.33, 3.54, 3.73, 3.91 The ring/pinion are actually much cheaper on the dana 44. Dodge used them in the 1st gen Viper and Grand Cherokee so I guess there's just more economy of scale. |
||
Posted on: 2009/2/11 6:02
|
|||
|
_________________
1985 Z51, ZF6 |
|||
|
Transfer
|
|
||
| mseven | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
if budget permits just do the 44. If buying a used one I would have it gone through regardless, before being assembled in the car. I would do at least the 3.4 ratio or larger (numerically).
|
||
Posted on: 2009/2/11 11:39
|
|||
|
Transfer
|
|
||
| dan0617 | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
What rear gear ratio do you have now?
This is my opinion and not all will agree, as was my above post, but..... If you have a 3.07, I wouldn't spend the money to do anything at this point. With your setup and street tires 3.42's or 3.54's would just be that much more tire blazing. Just put the right stall converter in to match your cam and intake powerband. A higher stall converter will make up most of the difference in gears. If you have 2.59's, I'd either buy a used D36 stock centersection with 3.07's and bolt it in (they go for about $300, this is what I did), or jump up to the D44 and then consider 3.42's or even 3.73's, but I would strongly suggest running drag radials on the back at that point. Most of the rear end breakages you hear about are either 1/2 shafts or spindles, and those parts are identical on the D36 and the D44. A large percentage of the D36 breakages are from people running 3.73's, or some 3.54's. Pretty rare to hear of a D36 with 3.07 gears breaking, and I've never heard of a D36 with 2.59's breaking, although it has likely happened somewhere. From my experience so far, I have run 1.7 60 foot times at the track and have ran probably 50 to 60 1.7 to 1.8 60 foot times on the street (yes, with the 3.07's and drag radials it dead hooked on the street just like at the track!) with no breakage yet. If I were you, I'd put it together, take it to a dragstrip on test and tune day and make a few passes just for fun. If your 60 foot times are higher than 1.7 I'd forget about it. If they are in the 1.6 range, I'd consider doing something. If you happen to pull off something in the 1.5 range, then the D36 is on borrowed time. It's all about budget. If you have an extra 5 grand laying around just put in a solid rear and be done. 2 grand give or take, do the D44. $500 or less, used D36 with 3.07's. Already have 3.07's? Don't spend anything and enjoy the hell out of your new setup! |
||
Posted on: 2009/2/11 13:54
|
|||
|
_________________
´89 Vert, 383, 230/236 cam, AFR 195's, LT Headers, HSR intake, 2800 stall, Zex 200 shot, ET Street Radials, tune by me. Runs were with D36 3.07's. On spray, 10.55 @ 132.78, 1.55 60 ft. On motor, 12.08 @ 113.15, 1.66 60 ft. |
|||
|
Transfer
|
|
||
| dan0617 | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
Quote:
I wonder if the high strength gears are much more durable? I've heard of ring gear breakage and of case breakage with the D36 but I don't know which one is more prevelant when running 3.54's or 3.73's. I don't think 3.42's are available for a D36, it's 3.54's. That doesn't matter alot though. I agree that if he is going to go through setting up gears he might as well go to the D44. But if he can pick up a used D36 centersection with 3.07's or if he already has 3.07's he might as well nail the converter stall and forget about the rear, it will be fine IMO. Now if this were a 6 speed car, I'd be saying he needs at least 3.42's, probably 3.73's, and I'd be saying he needs at least a D44, might be worth a look into a solid rear. |
||
Posted on: 2009/2/11 14:04
|
|||
|
_________________
´89 Vert, 383, 230/236 cam, AFR 195's, LT Headers, HSR intake, 2800 stall, Zex 200 shot, ET Street Radials, tune by me. Runs were with D36 3.07's. On spray, 10.55 @ 132.78, 1.55 60 ft. On motor, 12.08 @ 113.15, 1.66 60 ft. |
|||
|
Transfer
|
|
||
| bogus | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Grand Imperial Pooh-Bah
 
|
I would go looking for a D44 with (nominal) 3.33 gears.
When the 6spd first came out, it didn't get the 3.42 rear with an L98. It got 3.33 gears. When the ZR1 came out, it got the 3.42 gears. Now, for what it's worth, I have read where the stock rear gear is 3.42, 3.43 or 3.45... I have always wondered about the discrepency? I have read these numbers in the car mags, not just on the various forums. With the automatic, anything lower would just get way to frantic, I would think. It may not be an issue of MPG, but an issue of more relaxed cruising. |
||
Posted on: 2009/2/11 15:43
|
|||
|
_________________
The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me |
|||
|
Transfer
|
|
||
| Danspeed1 | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Elite Guru
|
My bad... 3.54 is what I was referring to, although your not going to notice a difference from 3.42 --> 3.54, I hardly noticed a difference from 3.08 to 3.42 (my car). I don't know if 3.42's are offered but I mentioned them as force of habit.
Again, Grind4it is specifically stating this is to be a street only car. I think we are getting too caught up in slicks, drag radials, and track times. We tried setting my fathers car up for "the track" and you know what, we never made it to the track once in the 10 years of ownership. Grind4it, it is my personal opinion that on a street car you should try (and I am sure you want to) to optimize performance as much as possible, but if you intend on driving this car more than a quarter mile up the road you should not let performance get in the way of drivability. As Central Coaster has said time and time again, all the modifications that have been done to his car have been done to increase performance, but also to complement and improve the daily driving experience. Thats what makes his car a blast to drive. Take it from the guy who over did it with the converter and tires, whats good for the track is not necessarily great for a 2 and a half hour trip on the highway and back roads. My suggestion, (this is just my opinion) would be to go with a modest converter for a well known, reputable manufacturer. I would not go crazy on the stall speed if it was inteded for daily driving. Figure no more than 3000 RPM. I would have to agree, if you have 3.07's in the D36, then run it. It will be nice around town and great on the highway. If you have anything less, then I would swap up to the D44 and shoot for the 3.33's or 3.54's. I would also have to strongly advise against the drag radials. I am not even running a drag radial, but I am running a really sticky tire, and i must say, in all styles of driving its a PITA. Why,... they wear fast, slip like crazy in the cold, and when they are warm they are noisy, and the catch and kick up ever little rock on the road. Hey, different strokes for different folks, thats all. There is no "correct" person here. You just have to decide what you would like out of the car. If you want more race, you lean towards Dan's side of the room, if you want more street, you lean towards Andy. I am somewhere in the middle. Just saying if I was to do it over, I would stick with my 3.42's but i would do less converter, and all season tires. P.S. heres a little clip of 500HP being put down on cold pavement (here in ny) on 275 BFGoodrich (old skool) Radial T/A. This car has 3.73's and a 9.5in 3200 Racing Converter. As you will see the car doesn't get that crazy. http://www.youtube.com/watch?v=cwd36KV02M0 DG |
||
Posted on: 2009/2/11 23:12
|
|||
|
_________________
1971 Chevelle SS (The Original) 1972 Chevelle SS 454 1995 Corvette Convertible 1996 Ford Explorer 2009 Cadillac CTS-v |
|||
|
Transfer
|
|
||
| BrianCunningham | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
Quote:
fixt |
||
Posted on: 2009/2/11 23:20
|
|||
|
_________________
Polo Green 95 LT1 6-spd http://mysite.verizon.net/vzevcp74/ 383 LT1/Vortech Supercharger/AFR heads/Rod end suspension/Penske-Hardbar dual rate coilovers/Wilwood 6pot brakes NCCC Governor: http://BayStateCorvetteClub.com |
|||
|
Transfer
|
|
||
| Danspeed1 | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Elite Guru
|
Thank you Brian,
How did you do it? DG |
||
Posted on: 2009/2/11 23:53
|
|||
|
_________________
1971 Chevelle SS (The Original) 1972 Chevelle SS 454 1995 Corvette Convertible 1996 Ford Explorer 2009 Cadillac CTS-v |
|||
|
Transfer
|
|
||
| BrianCunningham | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
You need to enable the HTML functions
To do that you need to hit the reply button, quick reply won't work. On the reply screen there's a bunch of options, one of which is enabling the HTML functions. |
||
Posted on: 2009/2/11 23:59
|
|||
|
_________________
Polo Green 95 LT1 6-spd http://mysite.verizon.net/vzevcp74/ 383 LT1/Vortech Supercharger/AFR heads/Rod end suspension/Penske-Hardbar dual rate coilovers/Wilwood 6pot brakes NCCC Governor: http://BayStateCorvetteClub.com |
|||
|
Transfer
|
|
||
| CentralCoaster | Re: 1985 C4 driveline RWHP question - LS1 Swap | ||
|
Senior Guru
|
Quote:
You might be better off looking for gold at the end of the rainbow. Those were a one-year only deal right? |
||
Posted on: 2009/2/12 0:45
|
|||
|
_________________
1985 Z51, ZF6 |
|||
|
Transfer
|
|
||
You can view topic.
You cannot start a new topic.
You cannot reply to posts.
You cannot edit your posts.
You cannot delete your posts.
You cannot add new polls.
You cannot vote in polls.
You cannot attach files to posts.
You cannot post without approval.
|
|