Pete M Posted October 1, 2017 Share Posted October 1, 2017 what about treating your truck to some sound proofing? maybe new window and door seals? Link to comment Share on other sites More sharing options...
Minuit Posted October 1, 2017 Share Posted October 1, 2017 2 minutes ago, Pete M said: what about treating your truck to some sound proofing? maybe new window seals? This is my thought. If I'm reading correctly the 6spd overdrive isn't that high. A real effort towards soundproofing with mass loaded vinyl completely changed the feel of my truck, to the point where the only thing I can hear in the cab at 70 is the wind, which a full set of OEM weatherstripping ought to fix. Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted October 1, 2017 Author Share Posted October 1, 2017 Just now, Pete M said: what about treating your truck to some sound proofing? maybe new window seals? Window seals are new along with NOS vent windows , I replaced all of that when I installed power windows / locks , and I retained the water/wind dams from a 95XJ . I also sprayed lizard skin sound deadener on the floors / back panel a month ago , I'm still using the original carpet minus the jute padding to prevent moisture on the floor boards . Link to comment Share on other sites More sharing options...
Pete M Posted October 1, 2017 Share Posted October 1, 2017 turn the radio louder? running out of ideas here you're driving a 80s era brick at highway speeds. it'll never match even the cheapest modern car in decibels. Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted October 1, 2017 Author Share Posted October 1, 2017 1 minute ago, Pete M said: turn the radio louder? running out of ideas here you're driving a 80s era brick at highway speeds. it'll never match even the cheapest modern car in decibels. Lol. I know . My black truck is considerably more quiet with the same drivetrain, lizard skin and all , minus the manual trans . My thought process is that the higher engine RPMs is the culprit, which is why I'd like to pursue the 6spd to drop some RPMs . Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 1, 2017 Share Posted October 1, 2017 15 hours ago, Strokermjcomanche said: I can assure that I'm at 70mph at 2700 rpms on my Toyo Open Country AT 31s . I'm using Nicks R.E.M. Along with a GPS and the correct speedo gear , and I've pace matched my buddies car at 70mph . Does the Renix R.E.M. read RPMs? If so, does it agree with your dash tach? I'm going to have to pickup a handheld unit to validate my dash tach RPMs. Anyone have any recommendations for a decent one? I have a timing light but it doesn't do RPMs..... Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted October 1, 2017 Author Share Posted October 1, 2017 1 minute ago, HOrnbrod said: Does the Renix R.E.M. read RPMs? If so, does it agree with your dash tach? I'm going to have to pickup a handheld unit to validate my dash tach RPMs. Anyone have any recommendations for a decent one? I have a timing light but it doesn't do RPMs..... Yes it agrees with my dash tach , I can read up to 4 things at a time with the R.E.M. . I keep the engine RPM , fuel trim , O2 readings , and TPS on most of the time ... Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 1, 2017 Share Posted October 1, 2017 1 minute ago, Strokermjcomanche said: Yes it agrees with my dash tach , I can read up to 4 things at a time with the R.E.M. . I keep the engine RPM , fuel trim , O2 readings , and TPS on most of the time ... Cool. Too bad it won't work on an HO. I think there's a way to measure RPMs with my Actron OBD1 scanner. Hmmmmm..... https://comancheclub.com/forums/topic/46667-actron-obd1-scanner/?tab=comments#comment-476254 Link to comment Share on other sites More sharing options...
johnj92131 Posted October 1, 2017 Share Posted October 1, 2017 Dropping the engine cruise RPM will make a difference in the cab noise environment. On my VW Passat diesel I found a kit from Europe that added a 6th gear to the stock VW 5 speed transmission. After installing the 6th gear kit, the change in cabin noise is very noticeable at highway speeds. But the MB 6 does not give you a longer 6th gear to slow the engine down. So I am guessing you would have to change the final drive ration. That means regear or get taller tires. I think the NV3500 trans for some Dodge trucks offers a .73 5th gear. Since you have a transmission guy who owes you some favors, perhaps going from a .78 to a .73 5th gear is a potential improvement? Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted October 1, 2017 Author Share Posted October 1, 2017 2 minutes ago, johnj92131 said: Dropping the engine cruise RPM will make a difference in the cab noise environment. On my VW Passat diesel I found a kit from Europe that added a 6th gear to the stock VW 5 speed transmission. After installing the 6th gear kit, the change in cabin noise is very noticeable at highway speeds. But the MB 6 does not give you a longer 6th gear to slow the engine down. So I am guessing you would have to change the final drive ration. That means regear or get taller tires. I think the NV3500 trans for some Dodge trucks offers a .73 5th gear. Since you have a transmission guy who owes you some favors, perhaps going from a .78 to a .73 5th gear is a potential improvement? Good idea John , I will have to ask him and see what he says . I'm sure it would be a cheaper route to go ... Link to comment Share on other sites More sharing options...
johnj92131 Posted October 1, 2017 Share Posted October 1, 2017 Don, Have you considered converting your H.O. to OBD2 specs? That would let you read the rpm directly from the engine ecu? Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted October 1, 2017 Author Share Posted October 1, 2017 16 minutes ago, HOrnbrod said: Cool. Too bad it won't work on an HO. I think there's a way to measure RPMs with my Actron OBD1 scanner. Hmmmmm..... https://comancheclub.com/forums/topic/46667-actron-obd1-scanner/?tab=comments#comment-476254 My innova scanner 3160 has the adapter and will read my 95 XJ RPM along with other readings Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 1, 2017 Share Posted October 1, 2017 6 minutes ago, johnj92131 said: Don, Have you considered converting your H.O. to OBD2 specs? That would let you read the rpm directly from the engine ecu? No, have not. I just want to verify the tach readings at this point. I get no noticable increased cabin noise at 70MPH than I do at 55MPH, so I'm pretty sure my tach's off. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 1, 2017 Share Posted October 1, 2017 3 minutes ago, Strokermjcomanche said: My innova scanner 3160 has the adapter and will read my 95 XJ RPM along with other readings That good. Does the Innova 3160 connect to the OBD1 diagnostic connector as my Actron does? If so, then I'm pretty sure my Actron will do the same thing. Time to break out the manual - again. Hope I'm not stealing your thread, but I'm glad this RPM topic came up.... Link to comment Share on other sites More sharing options...
Minuit Posted October 1, 2017 Share Posted October 1, 2017 My MT2500 reports engine RPM. I'd imagine your Actron probably does too. Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted October 1, 2017 Author Share Posted October 1, 2017 13 minutes ago, HOrnbrod said: That good. Does the Innova 3160 connect to the OBD1 diagnostic connector as my Actron does? If so, then I'm pretty sure my Actron will do the same thing. Time to break out the manual - again. Hope I'm not stealing your thread, but I'm glad this RPM topic came up.... Yep , the one by the Ecm (6 pin iirc ) Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 1, 2017 Share Posted October 1, 2017 Looks like I'm SOL. According to the manual, all the Actron can do RPM-wise is the idle speed test. It measures the RPMs at idle, then you can raise the RPMs up and down to see if the idle speed circuit responds. Doubt if I can crank it up to 2700RPM doing that. But I'll try it anyhow and see what happens... Link to comment Share on other sites More sharing options...
Eagle Posted October 1, 2017 Share Posted October 1, 2017 I don't see a problem. The jeep I-6 engine dates to well before overdrive transmissions became the norm. "In the old days," AMC vehicles with standard transmssions typically were geared to run at 24 MPH per 1000 RPM in top gear -- whether that was 3rd gear for a 3-speed or 4th gear for a 4-speed. If you do the math, that works out to 2500 RPM at 60 MPH, and 3000 RMP gave you a 72 MPH cruise. Set up like that, they lasted a couple of hundred thousand miles with just routine maintenance, and delivered what was then considered excellent fuel economy. I should know -- I've owned a bunch of them over the years. IMHO 2700 RPM at 70 MPH is just about perfect. I don't see any reason whatsoever to spend a bunch of money "fixing" something that ain't broke. Link to comment Share on other sites More sharing options...
Eagle Posted October 1, 2017 Share Posted October 1, 2017 Just now, Eagle said: I don't see a problem. The jeep I-6 engine dates to well before overdrive transmissions became the norm. "In the old days," AMC vehicles with standard transmssions typically were geared to run at 24 MPH per 1000 RPM in top gear -- whether that was 3rd gear for a 3-speed or 4th gear for a 4-speed. If you do the math, that works out to 2500 RPM at 60 MPH, and 3000 RPM gave you a 72 MPH cruise. Set up like that, they lasted a couple of hundred thousand miles with just routine maintenance, and delivered what was then considered excellent fuel economy. I should know -- I've owned a bunch of them over the years. IMHO 2700 RPM at 70 MPH is just about perfect. I don't see any reason whatsoever to spend a bunch of money "fixing" something that ain't broke. Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted October 1, 2017 Author Share Posted October 1, 2017 26 minutes ago, Eagle said: I don't see a problem. The jeep I-6 engine dates to well before overdrive transmissions became the norm. "In the old days," AMC vehicles with standard transmssions typically were geared to run at 24 MPH per 1000 RPM in top gear -- whether that was 3rd gear for a 3-speed or 4th gear for a 4-speed. If you do the math, that works out to 2500 RPM at 60 MPH, and 3000 RMP gave you a 72 MPH cruise. Set up like that, they lasted a couple of hundred thousand miles with just routine maintenance, and delivered what was then considered excellent fuel economy. I should know -- I've owned a bunch of them over the years. IMHO 2700 RPM at 70 MPH is just about perfect. I don't see any reason whatsoever to spend a bunch of money "fixing" something that ain't broke. While I agree with you Eagle some things have changed in the past 30 years . When these trucks first came out the speed limits were lower ( 55-65 around me ) now we have a lot of 70mph highways around here and when I'm going 70 I'm getting passed like I'm standing still. I don't plan on doing 80mph , but 75 mph is probably a realistic number ( and is a possibility that some highways will be raised to that ) so the RPMs will be even higher , and I would like to hear a little bit better too . Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 1, 2017 Share Posted October 1, 2017 52 minutes ago, Strokermjcomanche said: While I agree with you Eagle some things have changed in the past 30 years . Link to comment Share on other sites More sharing options...
omega_rugal Posted October 1, 2017 Share Posted October 1, 2017 so you are going to switch a tranny just for that? you can change the rear axle to 3.55 and or bigger tires...or put a better muffler...or improve soundproof the cab... no offense but you are trying to kill a fly with a bazooka Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted October 1, 2017 Author Share Posted October 1, 2017 28 minutes ago, omega_rugal said: so you are going to switch a tranny just for that? you can change the rear axle to 3.55 and or bigger tires...or put a better muffler...or improve soundproof the cab... no offense but you are trying to kill a fly with a bazooka No offense taken , but a muffler( which is stock and in good shape ) or a soundproofing ( which I've already done ) won't effect RPMs . The axles were just installed (from 3:07 to 4:10 ) and I have no intention to change them now , I would have went with 3:55s if I knew that this was going to be higher than my liking , it really is easier for me to change a trans ( my buddies trans shop ) than it is to regear / swap axles . Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 1, 2017 Share Posted October 1, 2017 2 hours ago, HOrnbrod said: Looks like I'm SOL. According to the manual, all the Actron can do RPM-wise is the idle speed test. It measures the RPMs at idle, then you can raise the RPMs up and down to see if the idle speed circuit responds. Doubt if I can crank it up to 2700RPM doing that. But I'll try it anyhow and see what happens... Hooked the Actron up and I was able to crank the idle RPM up to 1700RPM with it. The dash tach indicated just below 1900. So if the Actron is to be believed, the tach is reading about 10% high. The Actron was also able to read the programmed RPM and the feedback actual RPM which was also about a 10% difference. So if the dash tach is linear across the range, at 2700RPM indicated I'm actually running ~2430RPM. And that sounds about right with the 4.10 and 31s (30.5" actual). I'll have to play with my spare HO cluster and see if I can tweak the tach down a bit... Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 1, 2017 Share Posted October 1, 2017 8 minutes ago, Strokermjcomanche said: No offense taken , but a muffler( which is stock and in good shape ) or a soundproofing ( which I've already done ) won't effect RPMs . The axles were just installed (from 3:07 to 4:10 ) and I have no intention to change them now , I would have went with 3:55s if I knew that this was going to be higher than my liking , it really is easier for me to change a trans ( my buddies trans shop ) than it is to regear / swap axles . I had the 3.55 ratio originally with my rig before my D44 swap. You wouldn't want the 3.55 ratio with your setup, especially with the stroker. The ideal ratio for cruising and off the line would be 3.73 IMO Adam. I say if you can get the 6-speed in w/o breaking the bank it would be a hell of an upgrade. Link to comment Share on other sites More sharing options...
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