Going low speeds in high gears dangerous?
03-10-08, 10:20 PM
#1
Lexus Test Driver
Thread Starter
Join Date: Dec 2006
Location: Wilmington, North Carolina
Posts: 913
Likes: 0
Received 1 Like
on
1 Post
Going low speeds in high gears dangerous?
I'm just wondering if there is any scientific evidence that claims going around 40mph in 5th gear is in any way dangerous or bad in any way for your engine, specifically a 1JZ in a 92 SC3?
Maybe...depending too much on low spool? I dunno, just throwing ideas out there, i know the engine thrives off of high rpms (and so does the driver) but it's just a question that has been in the back of my head.
Maybe...depending too much on low spool? I dunno, just throwing ideas out there, i know the engine thrives off of high rpms (and so does the driver) but it's just a question that has been in the back of my head.
03-10-08, 10:23 PM
#2
Driver
Join Date: May 2006
Location: IN
Posts: 147
Likes: 0
Received 0 Likes
on
0 Posts
I'm not sure with your particular setup but with most engines you want to keep it above 1k rpm's. Anything lower than that can cause a heavy load on your engine. Heavy loads lead to more friction, heat, and engine wear.
What are your rpm's at 40mph in 5th gear?
My Integra was fine at those speeds.
What are your rpm's at 40mph in 5th gear?
My Integra was fine at those speeds.
03-11-08, 06:06 AM
#3
Lexus Champion
low rpm in a high gear is fine if you're cruising/coasting. if under throttle to accelerate, it absolutely pounds the bearings. you don't have much oil pressure at low rpms, so the bearings and engine are under load, while there isn't much oil being circulated.
you're basically asking the engine to do all the work without the advantage of using gears to multiply the torque. like taking off on a 21 speed bicycle in top gear. try it, you'll barely be able to move, because you only have so much power available and it's not enough to accelerate in top gear.
you're basically asking the engine to do all the work without the advantage of using gears to multiply the torque. like taking off on a 21 speed bicycle in top gear. try it, you'll barely be able to move, because you only have so much power available and it's not enough to accelerate in top gear.
03-11-08, 08:23 PM
#4
Lexus Test Driver
Thread Starter
Join Date: Dec 2006
Location: Wilmington, North Carolina
Posts: 913
Likes: 0
Received 1 Like
on
1 Post
At 40mph in 5th gear, maybe 2K on the dot, give or take a 100.
Excellent 19psi, thanks, I do this sometimes, starting from 15mph in 3rd only when its convenient and theres not a mustang beside me, ill make sure I watch that, thanks.
Excellent 19psi, thanks, I do this sometimes, starting from 15mph in 3rd only when its convenient and theres not a mustang beside me, ill make sure I watch that, thanks.
03-12-08, 07:21 AM
#6
I keep it above 1200 always, Cruising at 45 in 5th is ok, but never punch it.
but its actually better for your engine to be in 4th at 40mph, and surprisingly you will get better gas mileage if your in the proper gear.
your sweet spot on the powerband is around 2-3k rpm's. this is where you will get the most power per/gas and your engine is stress free and happpy.
but its actually better for your engine to be in 4th at 40mph, and surprisingly you will get better gas mileage if your in the proper gear.
your sweet spot on the powerband is around 2-3k rpm's. this is where you will get the most power per/gas and your engine is stress free and happpy.
Thread
Thread Starter
Forum
Replies
Last Post
dworak
RX - 2nd Gen (2004-2009)
6
06-23-20 09:10 PM
im4kar
RX - 1st Gen (1999-2003)
13
12-02-07 12:48 PM
