Engine overspeed by downshift - evolutionm.net
evolutionm.net - Home of the Lancer Evolution  

Go Back   > >
Log In 


Evo Engine / Turbo / Drivetrain Everything from engine management to the best clutch and flywheel.

Engine overspeed by downshift

Reply
 
 
 
Thread Tools Search this Thread
Old Apr 18, 2011, 12:46 PM   #1
Evolving Member
Personal Sales Rating: (0)
Thread Starter
 
Serbj's Avatar
 
Join Date: Apr 2011
Location: Massachusetts
Posts: 114
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: I do not; Hoon I do.

Engine overspeed by downshift

Will accidentally shifting to an inappropriately low gear damage something? This can occasionally happen when I'm on the 5th gear, slow down to negotiate a turn, and want to shift to 3rd gear while inattentively shifting to 1st gear.

What part of the engine will be damaged by this move? Rods, main bearing, transmission, or anything else?

How to prevent this kind of overspeed?

Thank you.
______________________________

By the way, I'm talking about a stock 4G63T with some insignificant bolt-ons, such as aftermarket intercooler, various gaskets, and head studs.

Last edited by Serbj; Apr 18, 2011 at 04:19 PM.
Offline
 
Reply With Quote
Old Apr 18, 2011, 12:55 PM   #2
Evolved Member
Personal Sales Rating: (41)
 
mdsevo06's Avatar
 
Join Date: Jan 2006
Location: San Diego
Posts: 1,432
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 06 WW IX GSR

Rod Bolts will stretch, causing damage to the bearings. The Bolts are the weak link in the stock motor, from over reving.
Offline
 
Reply With Quote
Old Apr 18, 2011, 12:56 PM   #3
Evolved Member
Personal Sales Rating: (2)
 
BLKCarbonEVO's Avatar
 
Join Date: Nov 2008
Location: VaBeach, VA
Posts: 3,464
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: EVO IX MR/SE

Valvetrain problems are your biggest issue. Could weaken the springs and cause a valve to fall into the pistons over time...

Try not to shift into 1st, when you mean to go into 3rd...

Rod bolts will be damaged but I would be more worried about that if they were under load, in this case they were not.

Mikey
Offline
 
Reply With Quote
Old Apr 18, 2011, 04:23 PM   #4
Evolving Member
Personal Sales Rating: (0)
Thread Starter
 
Serbj's Avatar
 
Join Date: Apr 2011
Location: Massachusetts
Posts: 114
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: I do not; Hoon I do.

Okay, so it damages the valvetrain and rod bearings. That sounds critical to the engine and it may not last long if this happens often.

I'll try hard to shift to the right gear... hehe
Offline
 
Reply With Quote
Old Apr 18, 2011, 05:11 PM   #5
Evolved Member
Personal Sales Rating: (16)
 
blknblubkrdude's Avatar
 
Join Date: Feb 2010
Location: Gillette, WY
Posts: 679
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: Yes

Yeah it's a bad deal to downshift and overspeed the engine.

My GF did a 5-2 downshift at 75mph (meant to go to 4th).

She hit a little over 8k, realized what she did, and pushed the clutch back in.
Real lucky i'd say!
Offline
 
Reply With Quote
Old Apr 18, 2011, 06:10 PM   #6
Evolved Member
Personal Sales Rating: (1)
 
awdordie's Avatar
 
Join Date: Dec 2010
Location: tennessee
Posts: 1,200
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 2003 evolution 8 and fully built 1990 honda crx

Its not quite as bad as say a 1-2-1 shift persay when racing but you should still avoid it altogether. From my experience the valves will hit the pistons and all hell breaks loose as you can imagine. I had just turbod my honda and installed a b&m short shifter, wasn't use to the new feel of it, and did a pull. Wot in first snatched second bout 6500rpms snatched what I thought was third dumped the clutch and bout went through the front window as my motor went well into the rpm range of a crotch rocket. When I tore it apart it had broken 2 valves bent 3 more and had a nasty hole in a piston and another was beat to crap as well.
Offline
 
Reply With Quote
Old Apr 18, 2011, 07:28 PM   #7
Evolved Member
Personal Sales Rating: (11)
 
cfdfireman1's Avatar
 
Join Date: Oct 2005
Location: Chicago
Posts: 4,164
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: EVO IX

Quote:
Originally Posted by Serbj View Post

How to prevent this kind of overspeed?

Thank you.
Sounds like you're a very good candidate for an automatic transmission.

Last edited by cfdfireman1; Apr 18, 2011 at 07:57 PM.
Offline
 
Reply With Quote
Old Apr 18, 2011, 07:41 PM   #8
Evolved Member
Personal Sales Rating: (5)
 
robertrinaustin's Avatar
 
Join Date: Dec 2003
Location: Work - New York, Alaska, Mexico or the Caribbean. -Home - Tx Hill Country
Posts: 1,858
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 08 Blk STi, 03 Blk EVO 8

I spun a rod bearing when I missed my 2-3 shift at the track in my VIII.
Offline
 
Reply With Quote
Old Apr 18, 2011, 07:43 PM   #9
Evolved Member
Personal Sales Rating: (10)
 
Butt Dyno's Avatar
 
Join Date: Jul 2002
Location: Why do they always call the Evo the Dark Side?
Posts: 1,273
Thanked 0 Times in 0 Posts

Drives: STU Evo, IS300 5MT daily

Quote:
Originally Posted by awdordie View Post
Its not quite as bad as say a 1-2-1 shift persay
http://www.urbandictionary.com/define.php?term=persay
Offline
 
Reply With Quote
Old Apr 18, 2011, 07:52 PM   #10
Evolved Member
Personal Sales Rating: (35)
 
wizzo 8's Avatar
 
Join Date: Mar 2005
Location: Chicago suburbs
Posts: 3,764
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 05 EB SSL Evo, 04 Blue R1(sold), 95 Nissan pickup lowrider(sold) 92 Mercury Gran Marquis(beater), 2013 R1

That's what mechanics call a money shift. Valves will float and hit the pistons. Worse case the valve head will break off and the cylinder walls will be destroyed. Learn to shift and this wont happen.
Offline
 
Reply With Quote
Old Apr 18, 2011, 07:58 PM   #11
Evolving Member
Personal Sales Rating: (0)
 
Join Date: Jul 2010
Location: Ohio
Posts: 470
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 06 IX MR SE, 95 Saturn SC2

Ur engine will go pop along with some of ur drivetrain
Offline
 
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
codes elkazX Evo X General 8 Feb 11, 2015 02:14 PM
Auto slow shift 2-3/3-4 when hot, cheap fix? rickb928 Lancer Tranny/Drivetrain Tech 4 Oct 4, 2013 09:07 PM
P0219 code and only has 2,500 miles. =[ roydollabill Evo X Engine Management / Tuning Forums 6 Jul 23, 2013 10:05 AM
Engine Overspeed turbosuckout Cobb AccessPORT 8 Jan 3, 2012 08:41 PM
"Overspeed" turbo failure? EVOEMS Evo Engine / Turbo / Drivetrain 3 Sep 4, 2009 10:50 AM


Tags
52, accidental, accidentally, damage, downshift, engine, evom, gear, lower, money, motor, overspeed, overspped, pop, shift, valves

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off



All times are GMT -7. The time now is 07:13 AM.