Hello all! So, I'm having suspension issues with the truck and really need them figured out. truck shakes at highway cruising speeds. It will smooth out if I move the wheel slightly (with the slack) and it'll get smoother and not be shaking. It's not death wobble like you see on YouTube but it is definitely annoying and NOT correct lol. I think tires may just need to be balanced and a good alignment. Front driver tire is also a weird wear (mud tires, each tread is up and down alternating, planning to get new wheels soon). Only thing I know that has been done to the truck suspension wise is a leveling kit.

 

To the next problem, when turning at slow speeds (parking lot speeds) the truck vibrates badly, more so when turning right. Also, when coming to a stop from like 5mph zone down to 0 it'll grind and rattle, even without brake engaged and the shake will be felt in all 3 pedals. I'm thinking wheel bearings? Rotors and all that I believe were replaced by P/O but not sure how good of a job they did due to other work on the truck....

 

Last thing is presumable powertrain related but I hear a noise right in the bellhousing... Doesn't sound like a deep knock like a beginning rod knock but it sounded the same as a video I found online and the guy said it was his flexplate being loose/cracked. They sounded almost identical but I have a flywheel due to it being a manual. Truck has a South Bend dual disc setup and the noise stays even with clutch pedal pressed. I'm not sure if the P/O replaced the flywheel or if it has 300k on it like the truck has or he did replace it and maybe didn't torque the bolts correctly.

 

Any and all suggestions is welcome! Whether it is for all 3 problems or just the one! 

 

Edit: Truck supposedly had all 4 ball joints replaced, calipers and rotors, front shocks at 300k, at 319k now.

 

Thank you

Dylan.

8 minutes ago, YeaImDylan said:

 

@Mopar1973Man I wanna know how your truck built 15psi in 2nd when you let your lady drive it and give it hell. I only start getting boost in 3rd and it’s maybe 15psi max. Most I’ll see in 2nd even at WOT is like 7psi max and she don’t Move very quick and then I lost that boost when shifting to 3rd (same when going from 4th to 5th) and my tires sure as hell don’t spin. I feel I should have quite a bit of power with a 64 and 125s with the quad wiretapped.

 

What sized tires are you running and what is your axle ratio? 

 

This is what makes or breaks a good setup. You need optimally after tires and wheels 3.55 to 3.73 final ratio to the ground. I've got 3.55 gears but with the 245/75 R16 tires my final ratio is 3.69:1 to the ground. Then I'm not running a monster huge turbo but a Hybrid HX35/40 which is (60/60/12). Speed wise I'm at perfect 2,000 RPM at 66 MPH and then at 2,500 RPM I'm doing 82 MPH this is a good proper ratio. Let's say with NV4500 transmission I'm in 4th gear (1:1 direct) by 25 to 30 MPH. 

 

Most go up to 35 inch tires on 3.55 gear and now the final ratio is more like 3.27 to the ground and the truck struggles to make power. 37 inch tires on 3.55 is a perfect 3.00 to the ground. Anything with 35 to 37 inch tires REQUIRE 4.10 axle gears. No way around this fact. 

 

For every ONE pound of rotational mass you add to the tires, wheels, driveline is like adding another 8 pounds on the frame. Bigger tires will always consume more fuel to get spinning or excessive heat the brakes because of stored energy and stopping. Hence why my brakes last over 200k miles per set. Not to mention going down in tires size lighten them even more. Reduction of rotational mass. 

http://hpwizard.com/rotational-inertia.html

 

So now you understand why I went down to 30 inch tire on 3.55 gear to enhance the torque output which it did, it reduced roughly 100*F off EGT's, it reduced my transmission temps by another 20 to 40 degrees, then improved towing MPG's 14 MPG towing my 31 foot travel trailer (Jayco). 

On 4/10/2021 at 10:56 AM, Mopar1973Man said:

 

What sized tires are you running and what is your axle ratio? 

 

This is what makes or breaks a good setup. You need optimally after tires and wheels 3.55 to 3.73 final ratio to the ground. I've got 3.55 gears but with the 245/75 R16 tires my final ratio is 3.69:1 to the ground. Then I'm not running a monster huge turbo but a Hybrid HX35/40 which is (60/60/12). Speed wise I'm at perfect 2,000 RPM at 66 MPH and then at 2,500 RPM I'm doing 82 MPH this is a good proper ratio. Let's say with NV4500 transmission I'm in 4th gear (1:1 direct) by 25 to 30 MPH. 

 

Most go up to 35 inch tires on 3.55 gear and now the final ratio is more like 3.27 to the ground and the truck struggles to make power. 37 inch tires on 3.55 is a perfect 3.00 to the ground. Anything with 35 to 37 inch tires REQUIRE 4.10 axle gears. No way around this fact. 

 

For every ONE pound of rotational mass you add to the tires, wheels, driveline is like adding another 8 pounds on the frame. Bigger tires will always consume more fuel to get spinning or excessive heat the brakes because of stored energy and stopping. Hence why my brakes last over 200k miles per set. Not to mention going down in tires size lighten them even more. Reduction of rotational mass. 

http://hpwizard.com/rotational-inertia.html

 

So now you understand why I went down to 30 inch tire on 3.55 gear to enhance the torque output which it did, it reduced roughly 100*F off EGT's, it reduced my transmission temps by another 20 to 40 degrees, then improved towing MPG's 14 MPG towing my 31 foot travel trailer (Jayco). 

Yeah we’ve talked before about my ratios... lol I’m on 35s with I’m assuming 3.55s. Surprisingly though, at like 65 I’m at like 1900 to 2k rpm in 6th

2 hours ago, YeaImDylan said:

Yeah we’ve talked before about my ratios... lol I’m on 35s with I’m assuming 3.55s. Surprisingly though, at like 65 I’m at like 1900 to 2k rpm in 6th

 

Are you sure about the 3.55:1 ratio?  Have you checked your speedometer against a GPS unit?  Only reason I am asking is because I have almost the same setup as Mike with the exception of me having an NV5600 (only a small difference in overdrive ratio). 

 

245/75 R16 tires

3.55:1 axle ratio

NV5600 transmission

Tire size recalibrated by Smarty S03

 

My tach is approximately 1950 rpms at 65 mph in sixth gear.  I have verified the speedometer with a Garmin GPS unit.  

 

- John

2 hours ago, Tractorman said:

 

Are you sure about the 3.55:1 ratio?  Have you checked your speedometer against a GPS unit?  Only reason I am asking is because I have almost the same setup as Mike with the exception of me having an NV5600 (only a small difference in overdrive ratio). 

 

245/75 R16 tires

3.55:1 axle ratio

NV5600 transmission

Tire size recalibrated by Smarty S03

 

My tach is approximately 1950 rpms at 65 mph in sixth gear.  I have verified the speedometer with a Garmin GPS unit.  

 

- John

No I have not, I have my quad running the speedo with my tire size and it reads higher than my oem speedometer. Are you assuming my axle ratio is higher? I’m not sure what exactly is in the truck to be quite honest.

47 minutes ago, YeaImDylan said:

I have my quad running the speedo with my tire size and it reads higher than my oem speedometer.

 

If you compared your Quad speedometer with a GPS unit and they agreed with each other, then I'm thinking you have 4.10 gears - which would be a good match with the tires you have on your truck.  

 

- John

With 285s, nv5600, and 410s 60 mph is 2k rpm on my truck. Check your glove compartment for a sticker that should have the factory gear ratio on it. You probably have 410s, the 35s are probably accounting for the +5 mph. 

I agree with @Tractorman. I believe you have 4:10 gearing too. Your rpm is not low enough for 35's and 3:55's at 65. I turn 2000 rpm at 70 with 265's and 3:55's.

Nv4500 transmission

3.55 gears

245/75 R16 tires

 

66 MPH is exactly 2k RPM

82 MPH is exactly 2.5k RPM.

 

Final to the ground is 3.69:1.

On 4/10/2021 at 10:48 AM, YeaImDylan said:

@Mopar1973Man I wanna know how your truck built 15psi in 2nd when you let your lady drive it and give it hell. I only start getting boost in 3rd and it’s maybe 15psi max. Most I’ll see in 2nd even at WOT is like 7psi max and she don’t Move very quick and then I lost that boost when shifting to 3rd (same when going from 4th to 5th) and my tires sure as hell don’t spin. I feel I should have quite a bit of power with a 64 and 125s with the quad wiretapped.

 

Was rereading the thread and this kind of caught my eye.

 

Sorry, novel incoming..

 

So @Mopar1973Man's turbo is only 4.5mm smaller on the compressor side but 13.4mm smaller on the turbine side, that's a bit over a half inch in diameter smaller. That, combined with the smaller exhaust housing (12 vs your 14) is part of what allows his turbo to spool so quick. The smaller housing keeps exhaust velocity up and the smaller turbine wheel has lower inertia allowing for the responsiveness. Basically, lighter wheel plus faster moving exhaust gases makes for fast spool. That's why the HE351CW is prized for its spool up ability. Its a 9cm^2 housing with the same sized turbine as the HX35. 

 

The other contributing factor is engine load. More load = more heat = more force on the turbine. I'm getting into sled pulling so most of my knowledge is based on this, so please bear with me. The more load = more force on the turbine is why some of the super stock guys (ones with the v-cut tires) sometimes have trouble with getting going in the beginning of the track. Even though they are pushing the motors north of 5500 to 6000 rpm, their turbos, mixed with only one gear create the need to slip the clutch enough to put a load on the motor and create enough boost to make the horsepower and torque needed to launch with 40k+ behind them. If they try to get moving before enough boost is made, the engine rpm falls too much, and falls under the turbo. There's not enough load, or rpm for that matter, to get the weight moving. Usually when they get the reset they rev a bit higher and slip the clutch a bit longer before letting all the way out and letting the truck do the rest. 

 

I bring this up because your turbo has a large turbine wheel and larger exhaust housing. That turbo would really shine with high load and higher rpms, it moves lots of air and would have less back pressure so EGTs would stay cooler vs something smaller. At lower rpms however, your turbo has enough open area that the exhaust gas velocity slows down and "blows through" through the turbine's open area without acting on the blades as much. 

 

This is an over simplified version and my understanding of how all this works so please take this info with a grain of salt. 

 

As for the 7 psi of boost in 2nd, the rpms just rise too fast and the total final drive ratio (trans gear ratio x transfer case ratio x diff gears = final drive ratio**) puts too little load (goes back to mechanical advantage here) on the motor for it to build any heat. Watch the EGT rise difference between 2nd, 3rd, and 4th. Within reason, more engine load = higher EGTs.

 

**this is different than the final ratio that @Mopar1973Man is mentioning. I think his is technically called effective gear ratio. It takes tire height into account to give an equivalent rear axle ratio of what the engine is "seeing." It's an equivalent based on a percentage I believe. The final drive ratio I am talking about is the actual amount of turns the motor will turn per 1 revolution of the wheel, no matter what size tire. Just wanted to keep that clear.

 

I hope this makes sense. and doesn't get too science-y for anyone, or seem like the ramblings of a madman lol.

 

Hope this helps shed some different light on why your turbo spools like it does @YeaImDylan.

On 4/14/2021 at 3:29 PM, Silverwolf2691 said:

 

Was rereading the thread and this kind of caught my eye.

 

Sorry, novel incoming..

 

So @Mopar1973Man's turbo is only 4.5mm smaller on the compressor side but 13.4mm smaller on the turbine side, that's a bit over a half inch in diameter smaller. That, combined with the smaller exhaust housing (12 vs your 14) is part of what allows his turbo to spool so quick. The smaller housing keeps exhaust velocity up and the smaller turbine wheel has lower inertia allowing for the responsiveness. Basically, lighter wheel plus faster moving exhaust gases makes for fast spool. That's why the HE351CW is prized for its spool up ability. Its a 9cm^2 housing with the same sized turbine as the HX35. 

 

The other contributing factor is engine load. More load = more heat = more force on the turbine. I'm getting into sled pulling so most of my knowledge is based on this, so please bear with me. The more load = more force on the turbine is why some of the super stock guys (ones with the v-cut tires) sometimes have trouble with getting going in the beginning of the track. Even though they are pushing the motors north of 5500 to 6000 rpm, their turbos, mixed with only one gear create the need to slip the clutch enough to put a load on the motor and create enough boost to make the horsepower and torque needed to launch with 40k+ behind them. If they try to get moving before enough boost is made, the engine rpm falls too much, and falls under the turbo. There's not enough load, or rpm for that matter, to get the weight moving. Usually when they get the reset they rev a bit higher and slip the clutch a bit longer before letting all the way out and letting the truck do the rest. 

 

I bring this up because your turbo has a large turbine wheel and larger exhaust housing. That turbo would really shine with high load and higher rpms, it moves lots of air and would have less back pressure so EGTs would stay cooler vs something smaller. At lower rpms however, your turbo has enough open area that the exhaust gas velocity slows down and "blows through" through the turbine's open area without acting on the blades as much. 

 

This is an over simplified version and my understanding of how all this works so please take this info with a grain of salt. 

 

As for the 7 psi of boost in 2nd, the rpms just rise too fast and the total final drive ratio (trans gear ratio x transfer case ratio x diff gears = final drive ratio**) puts too little load (goes back to mechanical advantage here) on the motor for it to build any heat. Watch the EGT rise difference between 2nd, 3rd, and 4th. Within reason, more engine load = higher EGTs.

 

**this is different than the final ratio that @Mopar1973Man is mentioning. I think his is technically called effective gear ratio. It takes tire height into account to give an equivalent rear axle ratio of what the engine is "seeing." It's an equivalent based on a percentage I believe. The final drive ratio I am talking about is the actual amount of turns the motor will turn per 1 revolution of the wheel, no matter what size tire. Just wanted to keep that clear.

 

I hope this makes sense. and doesn't get too science-y for anyone, or seem like the ramblings of a madman lol.

 

Hope this helps shed some different light on why your turbo spools like it does @YeaImDylan.

Thank you for that! Is it possible to swap turbines within mine and keep the housings? Mainly swapping the exhaust turbine to maybe make pressure easier/faster?

@YeaImDylan, it would be easier to swap on a wastegated 12 cm^2 housing.. It starts getting complicated when you start swapping around turbines and housings, Because you need a new housing with a new turbine wheel. My thread on turbo options has some more info on the turbo you have. 

 

 

@dieselautopower, is the 12cm^2 housing available separately for a 73.4 turbine?

There is a lot more for measurements and spool up and flow than one number from the wheel--- whether it be inducer or exducer. 

 

Here is the link

https://www.dieselautopower.com/s300-t3-turbine-housing-76-68-wastegated-he351-12cm-12cmt3he351wg68-13502

 

Turbo blanket is about $70 and will improve spool up by 3-5%.

 

 

These will also help spool up https://www.dieselautopower.com/crazy-carls-tunnel-ram-vp?Category_Code=

https://www.dieselautopower.com/pusher-intake-manifold-with-cross-air-for-1998-5-2002-dodge-cummins

 

But a properly sized turbo, smaller tires and proper gearing will make a huge difference.   Going from 33" to 31" tires made 100RPM faster spool up or more.

 

On 4/10/2021 at 3:56 PM, Mopar1973Man said:

Hence why my brakes last over 200k miles per set

Thought that was down to your exhaust brake not tyre size  or am I just missing something