Hippie Posted August 18, 2012 Report Share Posted August 18, 2012 Anybody here running a 3.42 (4T65E) or 3.43 (4T60E) final drive ratio with an L36 NA 3800 Series II? The new trans has to come back out of my daily driver Impala. It's a base model with 3.05 gears and feels a little undergeared to me, I have a set of 33/37 sprockets to change it to a 3.42 while it's out. It currently has a K & N intake, Magnaflow 2.5" downpipe with high flow Cat and U-bend delete and a DynoMax cat back with some very mild tuning tweaks with a Hypertech programmer. As soon as I can I plan on installing ZZP ER rockers and the HV3 plenum insert. Once those are in I'll get a real tune on the PCM. Just wondered if anyone was currently running them and how you liked them. Quote Link to comment Share on other sites More sharing options...
Addicted To Boost Posted August 18, 2012 Report Share Posted August 18, 2012 If you do a lot of highway driving, you probably won't like it. I have 3.29s behind my L32 and its nice in city driving, but it revs higher on the highway and kills mileage. Quote Link to comment Share on other sites More sharing options...
9lumina6 Posted August 18, 2012 Report Share Posted August 18, 2012 Just the stock 3.29's in the GT. Even that with an L36 gets worse highway mileage (28 mpg at 75mph) than my modded L67 with 2.93's (30-31mpg at 75mph). If you plan on doing alot of highway driving I'd stay with the stock gearing. I don't do a lot of highway trips with the GTP any more so I plan on eventually getting some 3.29's in there. Quote Link to comment Share on other sites More sharing options...
Hippie Posted August 19, 2012 Author Report Share Posted August 19, 2012 Both my other vehicles see a lot of highway driving and they have V-8's with 3.73's, I like them just fine. At 70 MPH with the 3.42 and 225/55-17's I'll still only be turning a hair under 2200 RPM, just about where the L36 finally starts making some torque but still far short of the TQ output of an L32 or L67 at the same RPM. 28-29 MPG? I'd love to get that kind of mileage! This is my 2nd L36 Series II with 3.0* gearing and neither one ever got better than 27 on it's best day. They are too far below their torque curve with those gears and OD. The L36 is no torque monster by any means, it needs some gear. Quote Link to comment Share on other sites More sharing options...
pshojo Posted August 19, 2012 Report Share Posted August 19, 2012 My L26 set up has 3:43 FDR, however I haven't been able to start the vehicle. I was hoping in next couple weeks, i'll be able to get harness fixed when I get more time back on the car. I also am running 1.9 ratio rockers and HV3 plenum insert with initial PCM tune. Quote Link to comment Share on other sites More sharing options...
pshojo Posted August 19, 2012 Report Share Posted August 19, 2012 My Grand prix GT with 3:29 gear ratio never got better than 27 mpg, unless I was on side roads doing 55mph. Then i'd get 28-30. So based on pure specilation, i'm guess my L26 would get 25? But my DOHC only got 24 on the highway. So as long as i don't loose gas mileage i'm good Quote Link to comment Share on other sites More sharing options...
Hippie Posted August 19, 2012 Author Report Share Posted August 19, 2012 My L26 set up has 3:43 FDR, however I haven't been able to start the vehicle. I was hoping in next couple weeks, i'll be able to get harness fixed when I get more time back on the car. I also am running 1.9 ratio rockers and HV3 plenum insert with initial PCM tune. When you get your's running and I get my rockers and HV3 in we'll have to meet up at Cordova when they have a test and tune night and pair 'em off. I'm about a half hour South of the QC on the IL side. Quote Link to comment Share on other sites More sharing options...
pshojo Posted August 20, 2012 Report Share Posted August 20, 2012 1/2 away? Muscatine? that is pretty cool you are close. What do you have? definately need to meet. When will you have yours running? Are you just in collecting stage? Quote Link to comment Share on other sites More sharing options...
Hippie Posted August 20, 2012 Author Report Share Posted August 20, 2012 (edited) 1/2 away? Muscatine? that is pretty cool you are close. What do you have? definately need to meet. When will you have yours running? Are you just in collecting stage? South of Milan on US 67. MIne is my daily driver, 2001 Impala base model with factory 3800 L36. The original 3800 blew up a couple months ago right after a LIM gasket replacement thanks to a defective thermostat, brand new. It had apparently already had one (LIM gasket) before I got the car and some of the damage may have already been done. The T-stat was the coup de grace. I lucked out and found a cherry 47,000 mile replacement out of '02 LS that had been t-boned. It goes in next week for the trans work. My employment future is kind of shaky right now so I'm holding off on buying the ZZP stuff until Spring or I sell off some of my SBC inventory and my Studebaker. Edited August 20, 2012 by Hippie Quote Link to comment Share on other sites More sharing options...
Euro Posted August 20, 2012 Report Share Posted August 20, 2012 Those Bullitts look great on there! I'd stick with the 3.29's. They're decent for highway, but not like the 2.93's are. I got a calculated 33mpg on my trip to Nebraska a couple years ago in my 2000 GT. Quote Link to comment Share on other sites More sharing options...
Hippie Posted August 20, 2012 Author Report Share Posted August 20, 2012 (edited) Those Bullitts look great on there! Thanks. I'd stick with the 3.29's. They're decent for highway, but not like the 2.93's are. I got a calculated 33mpg on my trip to Nebraska a couple years ago in my 2000 GT. I know I said I'd love to get 28-29 MPG but to be honest mileage is not my primary concern, the car is a lazy pig with the 3.05's. To go to 3.29's requires a $$$ differential and gear swap, to go to 3.42's requires only a sprocket swap while the trans is out for other work. The difference in RPM at 70 MPH between 3.29's and 3.42's is 80 RPM or in other words at 67.3 MPH with the 3.42's I would be turning the same RPM as 3.29's at 70 MPH........... I honestly doubt I'm going to hurt my mileage, in fact I'm halfway thinking it may improve slightly. I've seen it happen a few times before, particularly on low torque engines like the 3800, the engine may be turning a few more RPM but it's not working as hard to maintain the same speed. Edited August 21, 2012 by Hippie Quote Link to comment Share on other sites More sharing options...
pshojo Posted August 21, 2012 Report Share Posted August 21, 2012 Too bad I didn't know you before you bought your engine . Have spare L36 with 65k miles. Quote Link to comment Share on other sites More sharing options...
Hippie Posted August 21, 2012 Author Report Share Posted August 21, 2012 Yeah, I couldn't find anything around here with less than 90,000, drove to Bloomfield, IA. south of Ottumwa to get this one. It was worth it though, the car it was in was a cherry before it got tagged, somebody had taken REALLY good care of it. Dropped it in mine as is with fresh oil and new filter, didn't even change spark plugs. I was going to swap over my new stuff but there was no need. Still have my DOA original, didn't turn it in for a core. Haven't done the post mortem yet but it was hammerin' like a machine gun and the dipstick is bent about 45* right where it would come out inside the engine. Started tickin' South of Milan, sounded like a slight exhaust leak and it had the original exhaust so I didn't get suspicious. Next stoplight it was kind of sluggish and ticking a little louder but temp was good ( didn't have the SS cluster in yet so no oil press. gauge then ). When I crossed 280 on 92 I could hear the knockin' bouncing off the construction barricades. Recognized the sound right away then and knew the damage was done so I just put the hammer down. By the time I hit the West end of RI it was LOUD. Come around the bend before the Centennial Bridge and all the warning lights came on, SES started flashing and it died. I coasted to about 50 Ft. short of the traffic light on the West side of the bridge, called my wife to get hold of the towing company, grabbed my stuff and started hoofing it to work. There are some "interesting" people on the bike path between the old Armory and the Arsenal Viaduct at 10 P.M. on a Summer Friday night LOL but I think I spooked a few of them too. When you see an old white dude with a backpack in that area at night he's usually headed for Jim's Ribs to raid the garbage for his evening meal, most of the people I encountered gave me LOTS of room! A friend who works 2nd had left a few minutes early that night and saw me walking so he came back and picked me up. I walked into work with 2 minutes to spare but I was one tired SOB. He drove back in the next morning to give me a ride home, 50 mile round trip and wouldn't take a dime, now THAT is a friend! Quote Link to comment Share on other sites More sharing options...
Addicted To Boost Posted August 21, 2012 Report Share Posted August 21, 2012 I'd stick with the 3.29's. They're decent for highway, but not like the 2.93's are. I got a calculated 33mpg on my trip to Nebraska a couple years ago in my 2000 GT. Good to know... I'm thinking I'm going to put a regular GTP trans with the 2.93s into the 04 when the tranny bites the dust. For how much highway driving I do, The 3.29s don't benefit me. Quote Link to comment Share on other sites More sharing options...
Hippie Posted August 29, 2012 Author Report Share Posted August 29, 2012 Dropped it off this afternoon, supposed to be done Thurs. PM. Will wring it out this weekend and report back how it works out. My Hypertech Programmer will NOT let me change the gear ratio. Glad I didn't pay much for it 'cause it doesn't do much............ Quote Link to comment Share on other sites More sharing options...
z34Phoenix Posted September 5, 2012 Report Share Posted September 5, 2012 i have a gear swap to 3.73 with my dohc and still got about 24-26 mpg on highway. the gears actually helped my city mpg as i could be in 4th at 35 if i was just cruising. 3.29 vs 3.43 isnt that big a diff if you have the parts go for it! do you have a way to tune the shift points for the gear swap? Quote Link to comment Share on other sites More sharing options...
Hippie Posted September 5, 2012 Author Report Share Posted September 5, 2012 (edited) It's in and the car really likes it, me too. Ran into unexpected problems, my reverse band had a big chunk out of it and my differential was starting to shed teeth. We were not expecting that, my buddy had a reman'd diff in stock but had to order the band so I didn't get the car back until Saturday. My Hypertech programmer wouldn't allow for a gear ratio change like they said it did and when I tried to trick it by reducing tire size it didn't have enough range. I feel sorry for anybody that paid full price for one of those, I didn't pay anywhere near MSRP and I feel like I got hosed........ $69.95 full retail would be a more reasonable new price and after having one I'd still look for a 1/2 price sale or a used one! Speedo still off about 6 MPH and the shift points, rev limiter and cruise randomly weird out but when it isn't confused the car runs pretty good. Won't know about the mileage until I get the programming straightened out and the "new" wears off and I can keep my foot out of it LOL. So far my mileage doesn't appear to have been affected much. I have a reprogrammed ECM on the way from pcmperformance . Ordered it Sunday, they sent me an e-mail that it shipped yesterday, will hopefully be here tomorrow. Pretty good service for a holiday weekend. PCMforless, Overkill and Intense seem to be a lot better known but PCMforless had too much bad press and the other 2 seemed to be a bit more race oriented and their emphasis seems to be more toward the supercharged cars. These guys seemed a lot more "rounded" as far as the programming options they offered for "street" and N/A cars and I had a couple good recommendations for them. Hadn't found any negative press for them. Edited September 5, 2012 by Hippie Quote Link to comment Share on other sites More sharing options...
pshojo Posted September 6, 2012 Report Share Posted September 6, 2012 I can't wait to get my PCM back to, to see how it runs too. When you get yours back let me know what your RPMs are at 70mph . Quote Link to comment Share on other sites More sharing options...
Hippie Posted September 9, 2012 Author Report Share Posted September 9, 2012 PCM in and initial impressions are favorable, will wring it out a little more the next few days and report back but so far so good. I'm loving the 3.42's! GM should have made them an option. Quote Link to comment Share on other sites More sharing options...
Hippie Posted September 9, 2012 Author Report Share Posted September 9, 2012 RPM at 70 is a hair under 2500 on flat ground with a light head wind. I have one minor glitch, it hits the rev limiter for about half a beat on the 1-2 shift at WOT then shifts. Sending my stock ECM to them and they are going to put the tune in it with a correction for the 1-2 shift point/rev limiter glitch. He told me to send the other one back once mine is in and he'll correct it and send it back no charge so I have a spare. I thought that was pretty cool, couldn't be happier with the overall tune OR the service. Car pulls strong (for what it is) from idle to redline. The Hypertech program had two very noticable "plateaus", one at 1,800 and a really big one at 4,000. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted September 9, 2012 Report Share Posted September 9, 2012 hypertech, even in the OBD1 days, was always flaky and generally crap. Quote Link to comment Share on other sites More sharing options...
pshojo Posted September 25, 2012 Report Share Posted September 25, 2012 Have you had much of a chance to see if it effects gas mileage much, in town/Highway? Quote Link to comment Share on other sites More sharing options...
ReBlown47 Posted October 1, 2012 Report Share Posted October 1, 2012 yeah im only gettin around 28.1 mpg on the highway and thats with headers and around 2500rpms with 3.29 gears Quote Link to comment Share on other sites More sharing options...
pshojo Posted October 2, 2012 Report Share Posted October 2, 2012 So the 3:43 chain your getting 28? That's awesome. My 3.29 GP 2000 o GP got 26-27 mpg. That's awesome with the 3:43 Quote Link to comment Share on other sites More sharing options...
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