IS350 motor into IS250. - Page 6 - Lexus IS Forum
User Tag List

LinkBack Thread Tools
post #76 of 80 (permalink) Old 07-21-2010, 03:35 PM
Join Date: Oct 2009
Location: Richardson TX
Posts: 2,095
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Originally Posted by Knightshade View Post
And nothing to do with the actual question I asked regarding encryption.

I should've known better than to expect any useful information though... my bad!
Lets all say it together..."Knightshade was wrong... Knightshade was wrong..."

Get it now !!!

2004 IS300 MSM LSD Manual ..Hail damage written-off so now grand daughters car
2003 Pathfinder SE 4WD
IanH is offline  
Sponsored Links
post #77 of 80 (permalink) Old 07-22-2010, 08:02 AM
Join Date: Oct 2009
Location: Richardson TX
Posts: 2,095
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Originally Posted by TI-IS250MT View Post
Wow, you are just a little automatic 350 fan boy aren't you? You act like you know everything and every result when in reality you haven't experimented or researched anything. If the IS-F is indeed wider, then my bad thats a very interesting peice of information. 250 Manual getting worse millage is bull shit, and the EPA ratings are simply incorrect as I have driven both. My Manual has gotten up 32 MPG on long highway trips, I have had multiple 250 auto's for rental and they consumed more gas no doubt and didn't reach the same numbers on the highway trips. There is less loss in a manual you can't argue that. Theres nothing wrong with the manual tranny in this car either, so you writing it off as a peice of shit means nothing to me as well. You sir are negative and want to tell everyone why something won't work and to be happy with the factory offerings. In the end there is no point in responding or discussing this point any further because your attitude supports a non-innovative discussion which I have no interest in.
I can confirm I have driven similar model engine etc with Auto and Manual for 4-6 weeks each (they were long term rentals)
The Auto did much worse mileage.

Any real road experience for the other way round ??? Knighshade ??

Re: EPA mileage,
Car and Driver got suspicious and ran same car with different transmissions because they did not believe the EPA ratings.
You know, hundreds of miles on the streets, swapping drivers, rotating the lead.

Guess what, the higher EPA rated car ended up with lower mileage !!!

Now our own IS300 is generally accepted on THIS forum to have 10 -20 BWHP less with the Automatic with engine like for like, ie stock vs stock, I/H/E etc....
Less HP, because of higher transmission losses, Less mpg.

So why is the EPA rating out to lunch, Car and driver explained it, higher losses in the transmission due to high pressure hydraulic pumps used to drive components.

So we have actual experience on the road and theory to back this up. Pretty conclusive I would say.

2004 IS300 MSM LSD Manual ..Hail damage written-off so now grand daughters car
2003 Pathfinder SE 4WD
IanH is offline  
post #78 of 80 (permalink) Old 07-22-2010, 10:59 AM
Join Date: Aug 2007
Posts: 5,052
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Got a link to the Car and Driver testing? I'd certainly be interested in looking at it.

The IS300 is probably a poor example to use, as it's a car using a pretty ancient transmission by today's standards.

The manual in the 250, while being a crap transmission, at least has the same # of gears as the auto so it's a fairer comparison to it's modern auto counterpart, and 32 mpg for a manual 250 is hardly impressive when there's folks who've hit 30 in a 350, and considerably better than 32 in an automatic 250. (I know I've seen as high as at least 38 highway in a 250 auto from some folks).

I'd say that today if you're buying a 90 hp Kia or something where you pick between a 5-speed manual and a 4-speed auto the manual will retain it's traditional benefits (slightly less drivetrain loss, and slightly better efficiency due to having more gears available)... But if you're buying a more expensive model that can offer a modern automatic transmission those benefits largely vanish (and in many cases you get worse mileage with the manual, and you're certainly going to be slower given humans shift far less reliably and far less quickly than computers do).

The computers help considerably with mileage too, they know better than you do the most efficient gear for the car to be in... which is another reason you'll increasingly see autos offering better mileage than manuals.

Interestingly the auto even has lower emissions (as well as better mileage from a non-EPA source)... this according to a 250 owner in the UK who bought his auto because it was both rated better for mileage (in the UK, so no EPA there) and the lower emissions (since it impacts taxes on the vehicle there)-

Check post #6 for that

Oh, and Canada rates the manual with worse mileage than the auto too (again a non-EPA government source)

Last edited by Knightshade; 07-22-2010 at 11:31 AM.
Knightshade is offline  
post #79 of 80 (permalink) Old 09-09-2010, 09:38 AM
Join Date: Jul 2007
Location: South Africa
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Hi all you arguing old woman. .lol... Ive got the auto as a result of Lexus.. I bought the manual and they admitted there to be an issue in design. They made a swop after communicating with Japan about the problems and it was confirmed there is a floor in the design. They wouldn’t have replaced the car if the manual had no problems.
I was also thinking of swapping my engine for a 350 as they are not sold in South Africa. The choices are either buy a 250 or an ISF. After reading this I must say I would rather trade in and pay the difference for the isf. Better to play with the older is300. Ive got one of those with an 3uz and that’s a lot of fun.. What would you think of taking the isf motor and swapping the block for the 570 motors and going with a blower? Would be a bit pricy but should be quite the mod. Was chatting to Lexus about that idea and they seem to think it is possible. That should be a bit of fun.. Shooting in the dark with a lot of cash but mmmmmm.. Would be a beast
kiwiroadkill is offline  
post #80 of 80 (permalink) Old 07-04-2014, 09:48 PM
Join Date: Mar 2005
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
is350 and is250 have the same transmission?
TDR300 is offline  
Sponsored Links

  Lexus IS Forum > 2nd-Gen IS250/IS350 > Go Faster

Quick Reply

Register Now

In order to be able to post messages on the Lexus IS Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself. If your address is invalid, you will likely lose access to the site.

Email Address:


Current users viewing this Thread: 2 (0 members and 2 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Forum Replies Last Post
IS350 Motor Oil - what do you use? Slick Speed IS350 Owner's Forum 20 05-14-2008 07:37 PM
Chrome Lexus IS250 at Australian Int. Motor Show gbb357 General Discussion 34 10-31-2006 06:58 AM
Is350/is250 @ Sema 05' (Speed Magazine and Mackin Industries Lexus IS350) IS300eR General Discussion 51 10-22-2006 06:27 PM
IS350 5.3 13.9 on Motor Trend VADER141 General Discussion 22 12-06-2005 09:52 PM
IS250 Motor Vs IS350 Motor M3This General Discussion 2 03-29-2005 09:05 PM

Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome