Does anyone revvvv like this?

[Homeskillet43]

So I recently aquired a 2003 MM. It seems to be reving to high for me. See the picture, when I am driving 80mph the tach reads 3,000rpm. I do have the 4.10 gears, with headers, aero exhaust, and 19in rims. My mpg are an average of 16 that includes highway and city driving.
Please let me know if your MM is does the same.

[RubberCtyRauder]

3000 rpm is about right for 80mph with 4.10 gears..also no pic is in your post. I assume you have atune? make sure the tune compensated fior the tire diameter.

[justbob]

Damn I don't miss those days! My 4.30's back then used to scream at 80mph and up! She purrs right on along now.


Builder Of Badassery

[Homeskillet43]

I have a tuner not sure how to use it. This is crazy if this is normal. 16 miles to the gallon is crazy.

[RubberCtyRauder]

Do you know who's tune? You may have to put 3.55 gears back in it..Do you drive it hard all the time? Doesn't matter what car your in..80mph sucks gas in any car. Also, what size rear tires are they..go read the sidewall number and post it and what tuner is it?

[gdsqdcr]

I coming from time to time I mine and average around 17/18mpg. That is with me cruising around 72 on the freeway when I can. Straight highway I have seen almost 20. I have 4.10's, stock rims with 265's in the rear, a Zack tune and on California gas.

[Homeskillet43]

I do understand traveling at 80mph is not the best fuel consumption, however these numbers are very low.
I have 245/45/19 in the front and 275/45/19 in the tear.
I guess I am getting smiles per gallon as someone once told.

[Mr. Man]

Make sure you don't have a shifter cable out of alignment. I know my car used to occasionally read it was in D but was really in 2nd. I used to bump it into N and it would settle into D then pop it back into D and it would be fine.

[Homeskillet43]

My shifter cable is out of alignment. I thought I only had a problem going into reverse from drive. Will check that out.

[RubberCtyRauder]

They are not that low. In my daily driver I lose 2.5 to 3 mpg if I go 80 vs. 70 on the highway. Rear tire size is close to stock height. What octane are you using ? What octane is the tune for ?

[Homeskillet43]

92 to 93 octane. Not sure what the tune is for the car. It is a SCT Tuner.

[jwibbity]

If you think with 4.10s at 80 mph your going to get anywhere close to 20mpg, you are sadly mistaken.

Either slow down or switch back to 3.55s to get better MPG.

[Homeskillet43]

The issue I am having was wondering if anyone else MM revs at 3000rpm at 80mph. Lets not get it confused, I do not travel 80mph everytime I get in the car. I am new to the car and trying to understand it's dynamics. This is an everyday car for me and trying to maximize my fuel consumption.

[RubberCtyRauder]

At 70 mine is at 2500 rpm so 3000 at 80 is about right . I have 4.10 gears. Daily driver my recommendation is go back to 3.55 gears and have Mos speed shop here give you a new tune

[Homeskillet43]

So that brings me to another question why did you change to 4.10?

[RubberCtyRauder]

Mines not daily driver. I bought it this way, this car is more set up for the weekend drag racer. 4.10 get the heavy car up and moving into the powerband quicker

[1Marauder]

CORECTED!!! WENT FOR A CRUISE TO VERIFY

And EXACTLY WHY I DONT HAVE 4.10's, as I drive on freeway in mine (to Marauderville or to the coast), and that would drive me batty.

I drive 85 and tach just above 2400. 95 is perfect around 2700, car hunkers right on down and sails along 100mph about 3000 rpm. I love the BEAST!

But I thought about this... I do not really drive in traffic at all, and I do turn OD off in town almost every time, AND I have an AWESOME TUNE!


PS CHECK OUT THIS TEST MULE WITH MICHIGAN PLATES! FOUND IT ON THE WAY TO VEGAS!!!!

[MyBlackBeasts]

Pre-boost with Lidio 4.10 tune I consistently got 20.5mpg at 75mph.

You probably have other issues.

[Homeskillet43]

So on these 3.55 gears. How do you go about picking the right ones? I have seen some as low as $123.00 and upwards of $300.

[martyo]

So on these 3.55 gears. How do you go about picking the right ones? I have seen some as low as $123.00 and upwards of $300.

You could probably post a wanted add here and get a set cheap.

Then again after you swap you WILL miss he 4.10s.

[RubberCtyRauder]

8.8 inch. Gear manufacturer of your choice. Installer of your choice. Have your tune ready to download . Try the vendor here, Sparta Performance.

[ginger]

3k rpm @ 80 is about right for 4.10s. Could be in the tune. I put over 1000 miles on the highway on mine last week and saw as high as 22mpg.

I do average 16-18 for mixed driving, and I don't keep my foot out of the throttle.

Sent from my VS985 4G using Tapatalk

[Blown3.8]

Is your converter locking OP? With your tire size and 4.10's, I come up with 2700 rpm with a locked converter. If your converter doesn't lock you will be wasting a lot of fuel.

With the converter slipping 11% that gets you to 3000 rpm at 80.

[ctrlraven]

I think you might have AConvertedChevy's car.

Did you buy it from someone in DE?

[Homeskillet43]

Blown3.8 I don't know what it means for a a converter to lock up.

[rauder88]

I agree I am at 2500 RPM at 75, stock rear tires with 4.10's. I rarely go 80 but it is right about 2700 rpm. Maybe you have a stall converter without a lock up clutch or it may be turned off in the tune, or you have 4.30 gears.

[Homeskillet43]

I do have aconvertedchevy car.

[ctrlraven]

I do have aconvertedchevy car.
When doing 80mph, do you have O/D off or on?

The factory tach is not 100% accurate btw, mine is off by 200ish when comparing to a digital readout via obd2.

Performance Evolution in DE may have done the tune for that car, that's if he got one after the headers went on.

[Homeskillet43]

Overdrive is always on. My digital readout tach aND the one on the dash have the same readings.

[jwibbity]

Using an RPM calculator, 28.74in tire height (275/45/19), 80mph, 4.10 gear ratio should be 2688 with a 0.7 OD (4R70W)

Same specs but 4.30's get you closer to what your experiencing at 2819 rpms

http://www.ringpinion.com/Calculators/Calc_RPM.aspx

4.30's would explain your RPM's and your worse than normal gas mileage.

[ctrlraven]

When I had 265/50R18 rear tires I was around 2800 rpms at 80 mph.

275/45R19 is about 701 revs per mile and 28.8" in diameter
265/50R18 is about 709 revs per mile and 28.5" in diameter

A 255/55R18 is about 694 revs per mile and 29" in diameter.

I'm running 255/55R18 now, I'll see what my rpm is at 80 on my way home tonight. I would think since your diameter is slightly larger than the 28.5" diameter it should read just a hair lower than around 2800 rpms. I get about 18/20 mpg regardless of whatever tire combo I have on at the time since I switch between summer/winter setups.

Since you have headers, if the car never had a dyno tune the air/fuel ratio will be off some, and slow moving or stop and go traffic eats the gas up quicker. These cars are really meant for highway cruising speeds because of their weight and where the engine produces its power.

[Homeskillet43]

The tire height I got was 28.74, my rear tires are 275/45/19.

Using an RPM calculator, 28.74in tire height (275/45/19), 80mph, 4.10 gear ratio should be 2688 with a 0.7 OD (4R70W)

Same specs but 4.30's get you closer to what your experiencing at 2819 rpms

http://www.ringpinion.com/Calculators/Calc_RPM.aspx

4.30's would explain your RPM's and your worse than normal gas mileage.

[jwibbity]

The tire height I got was 28.74, my rear tires are 275/45/19.

I edited the post, but its still the same either way

[Homeskillet43]

I was told the members of MM.Net are great, but is an understatement. You guys are amazing in your efforts to help me. This car definitely needs a better or different tune. I will be going to the Marauder meet in Leesburg, VA and don't want to spend all my money on gas getting there.

[ctrlraven]

On my drive home, here is what I got.

60 mph - 2067 rpms
70 mph - 2334 rpms
80 mph - 2670 rpms

that's with 255/55R18 (29" dia) rear tires, 4.10 gears and 3500 stall converter.

[Homeskillet43]

Sounds like I need to get Betty Lou checked out real soon. Thank you ctrlraven for the test. I really appreciate it.

[Blown3.8]

while cruising and you step on the gas a little do the rpms flare up and mph doesnt raise fast or is it more like a manual car where the rpms slowly move up kind of equal to the mph?

If they flare the torque converter isnt locked and is wasting fuel. and building heat.

[Homeskillet43]

This thing drives like a manual.

[Mesencephalon]

2700 at 80 is normal for me with 3.55 gear. I drive at 80 40 miles twice a day on a mostly empty I-840 on way to Nashville every day. It crawls a bit higher if i cruise at 85 but I don't see a steady 3000 until I'm on cruise at 95. She's smooth. at 80 I get a quarter tank a day of 93 octane, or about between 18-20mpg.

[Homeskillet43]

M.I.B those are some great numbers.

[Pat]

On my drive home, here is what I got.

60 mph - 2067 rpm's
70 mph - 2334 rpm's
80 mph - 2670 rpm's

that's with 255/55R18 (29" dia) rear tires, 4.10 gears and 3500 stall converter.

I have almost identical #'s, same equipage and this equates to 22+ MPG @ 70 MPH with centrifugal S/C and 39 lb injectors, three different tunes over the years. DR's, HPP racing, and now Mo's.

Cheers.

[Homeskillet43]

Perhaps I have a turbocharger or supercharger that I don't know about.

[RubberCtyRauder]

You might have 4.30 rear gear or the tune might be off with tire size..Need to raise rear (turn off air suspension intrunk) and get a friend to turn a rear wheel one revolution while watching how many times the driveshaft turns. is it more like 4 x or like 4 and 1/3 times.

[martyo]

Perhaps I have a turbocharger or supercharger that I don't know about.

Let me get in here before Zack does.

Are you $%^&* serious?

[Homeskillet43]

Martyo not sure what you are referring to. Is who serious about what?


Let me get in here before Zack does.

Are you $%^&* serious?

[ctrlraven]

Let me get in here before Zack does.

Are you $%^&* serious?
I think he may have only been half serious. lol

Martyo not sure what you are referring to. Is who serious about what?
He was referring to you in a joking manner about saying you might have some FI that you don't know about.

[martyo]

He was referring to you in a joking manner about saying you might have some FI that you don't know about.

Plus I got to pick on my buddy Zack all at the same time.

All in one day.

[Spectragod]

I recently got new shoe laces.......:D

[justbob]

Nothing like knowing what you bought! [emoji6]


Builder Of Badassery

[Bluerauder]

Nothing like knowing what you bought! [emoji6]


Builder Of Badassery


When he shows up at the ABT in Leesburg, Va later this month, we'll point out anything under the hood that looks suspicious. :rofl:

[Pat]

What does FI mean?

Ahh, I get it now Charlie; Forced Induction.

Thanks for the clue.

[Bluerauder]

What does FI mean?


Ha, Ha .... I was waiting for that !! :rofl: It's just the opposite of NA. :)

[Joe Walsh]

He was referring to you in a joking manner about saying you might have some FI that you don't know about.

Has anyone ever been blown and NOT known about it!?!?.....:eek:

:P


errrrr......their car that is!

[ctrlraven]

When he shows up at the ABT in Leesburg, Va later this month, we'll point out anything under the hood that looks suspicious. :rofl:
Nothing suspicious looking.
https://scontent-iad3-1.xx.fbcdn.net/hphotos-xpf1/v/t1.0-9/10157213_10201882421517429_348 8076077797018062_n.jpg?efg=eyJ pIjoidCJ9&oh=e2c76108834a63925c3aa418d76 3eeac&oe=56948C99

[Joe Walsh]

Nothing suspicious looking.
https://scontent-iad3-1.xx.fbcdn.net/hphotos-xpf1/v/t1.0-9/10157213_10201882421517429_348 8076077797018062_n.jpg?efg=eyJ pIjoidCJ9&oh=e2c76108834a63925c3aa418d76 3eeac&oe=56948C99

Looks suspiciously clean and well lit!

[chief455]

I do have aconvertedchevy car.
I'd contact him and get your cars specs on paper.
find out what tune you have, and flash it in again using correct gear ratio and tire revs/mile

this should ensure speedo accuracy -FYI - your dash tach and any other tach reading from the ECM will match, does not mean they are correct.
your 16 mpg? I get ~18 superchargged w mods in my sig.
myy tire is ~28" tall and I'm ~2800 at 80mph with OD on.

[Bluerauder]

Nothing suspicious looking.


Those red valve covers look suspicious .... Suspiciously GM flavored !!

[Homeskillet43]

I got a tune from Marty and now I am at 80mph I am about 2700 to 2800. My shift points are smoother and better. I can't wait to see the miles per gallon changes as well. Thank you everyone for the help and support. I really appreciate the time and effort you have invested in my issues.

[AConvertedChevy]

Hope you're enjoying it Corey!

Car was tuned for 93 octane on all 3 tunes on the SCT Tuner I gave you. I have 3.55 gears here if you'd like them, free-o-charge. The tune that was on the car was done by the PE folks in middletown Delaware as someone said. They tuned it but left the Zach tune shift points on the tune it was running when you bought it. I never really liked it but it did absolutely rip in certain ranges. I'm glad to hear you returned it because it deserved that! Be sure the numbers on that scangauge are correct if you are using that to determined fuel milage. I don't ever recall using it for accurate gas mileage readings because I didnt care/didnt want to know :). The shift linkage could surely use a tightening. Those wheels are kind of heavy as well, may consider some light weight 18s if you are hoping for better milage/acceleration.

Give me a call if you have any questions, I'll do my best to help. I'm typing this from my SRT 300......I dark sided...I know. But now I've owned a muscle sedan from each of the big 3. Life goals complete.

Miss all you goons!

ML

[Homeskillet43]

ML I love the car and I get compliments on the car very often. I was not using the scan gauge to determine miles per gallon, I was using the amount of mileages and dividing it by the number of gallons used. I was only getting about 12 to 15 miles to the gallon. That was mix of city and highway driving. My navigator got better gas mileage. I got the tune from Marty and the car drives so much better for me. The shift points are different and my 0 to 60 decreased by 2 seconds. With the new tune I am getting about 17 to 20 miles to the gallon mixed. Thank you for saving the car until I could purchase. I will take the 3.55 gears, but I think I will stay with the 4.10s.
Congrats on the SRT 300
P.S The exhaust on this car is crazy loud. That was from one of the members here saying that when we were all driving in line.