Avensis T25 Diesel gearbox on petrol

[Pingman21]

As far as I know there's no T25 Avensis 6 speed Petrol cars and I really find it high revving on motorways, does the 6 speed Diesel gearbox fit?

[Konrad C]

2 hours ago, Pingman21 said:

As far as I know there's no T25 Avensis 6 speed Petrol cars and I really find it high revving on motorways, does the 6 speed Diesel gearbox fit?

I will say no!

The Celica 6 speed will fit, but the close ratios are practically the same as the Avensis. 

I had a Mk1 Avensis and now own a Mk3 Avensis. The question is - will the Valvematic gearbox fit the VVTI engine?

Another fact is the VVTI does not have the torque to pull the long gearing. Anyone who has driven a manual 6 speed Valvematic will know that the engine needs to be above 3000 rpm to any meaningful power.  

I used to own a Vauxhall Cavalier and that had long geared 5 speed. The 2 litre Avensis also has long geared 5 speed. Now if that fitting the 1.8, it would lower the revs. The gear ratios are matched to the engine torque, vehicle weight and drag factor.  Most petrols are geared to 3000 rpm at 70 mph, some lower, some higher. My Mk3 is showing 2500 @ 70 mph.

Unless you are a mechanic and have access to tools and spare gearbox, plus some spare cash, I would not bother.

What about sound deadening?  

 

   

[Pingman21]

2 hours ago, Konrad C said:

I will say no!

The Celica 6 speed will fit, but the close ratios are practically the same as the Avensis. 

I had a Mk1 Avensis and now own a Mk3 Avensis. The question is - will the Valvematic gearbox fit the VVTI engine?

Another fact is the VVTI does not have the torque to pull the long gearing. Anyone who has driven a manual 6 speed Valvematic will know that the engine needs to be above 3000 rpm to any meaningful power.  

I used to own a Vauxhall Cavalier and that had long geared 5 speed. The 2 litre Avensis also has long geared 5 speed. Now if that fitting the 1.8, it would lower the revs. The gear ratios are matched to the engine torque, vehicle weight and drag factor.  Most petrols are geared to 3000 rpm at 70 mph, some lower, some higher. My Mk3 is showing 2500 @ 70 mph.

Unless you are a mechanic and have access to tools and spare gearbox, plus some spare cash, I would not bother.

What about sound deadening?  

 

   

The cams are different in the Avensis engine it does not need to rev so high, I really notice how hgh it is revving compared to other cars I'e had, it does 70 at 3000 and the fuel economy and noise suffer from that, be nicer if it did 70 at 2500, or my preference is 2000!

I did not know the 2.0 had longer gears, what revs does the 2.0 5 speed do 70 at?

More sound deadening would also help allot as as lovely as the car is it is quite droney on the motorway :(

 

[Konrad C]

8 hours ago, Pingman21 said:

The cams are different in the Avensis engine it does not need to rev so high, I really notice how hgh it is revving compared to other cars I'e had, it does 70 at 3000 and the fuel economy and noise suffer from that, be nicer if it did 70 at 2500, or my preference is 2000!

I did not know the 2.0 had longer gears, what revs does the 2.0 5 speed do 70 at?

More sound deadening would also help allot as as lovely as the car is it is quite droney on the motorway :(

 

Iain,

For a petrol to pull 2000 rpm @ 70 mph, the torque will have to be double and match diesels. That means adding a turbo. Also the spacing between each ratio would be wide.

Using the top gear mph per 1000 rpm formula, The petrol 1.8 is rated at 23mph per 1000mph. Factor in speedo error with over reads, that is 3000 rpm at 70 mph. The 2 litre is rated at close to 25 mph per 1000 rpm = 2800 rpm at 70 mph. My 1.8 Tourer is showing 2500 rpm at 70 mph.

From experience, my old 1.8 leanburn was nice at 70 mph and the engine had a nice high pitched hum, and not noisy. The Tourer is okay at 2500, but at 3000 rpm the engine has a boomy sound that the leanburn does not. I have been in a 1.8 VVTI and is smooth with a revvy sound and no boom. It is gear the same as the leanburn.

I have videos from last year of my old Mk1 and Mk3 on the motorway. I tend to play music so it would be hard to judge how loud the engines are. The loudest noise from both is tyre roar!

This is why I mentioned sound deadening. The leanburn and the VVTI engines are very efficient on fuel and get well into the 40's mpg at motorway speed. This is from experience. I don't think the fuel economy be that much improved with a 6th gear, because you will have to use a little more fuel to pull the longer gear. I noticed this in the Tourer, and have forced to drop down to 5th on inclines, where the leanburn is within it's power band. This why I was not fixated with revs. Had power and economy.

Unless the gearbox is broke, save the money and get sound deadening!    

[Konrad C]

Can I add, that I looked in an old issue of Autocar which had the mph vs rpm figures for road tested cars, and the Honda Civic 1.8 2006 - 2011 is geared at just under 24 mph - 1000 rpm, whilst the Avensis 2 litre 2003 - 2008 is geared closer to 25 mph per 1000 rpm. The following data from a site called cars-data confirms this fact:-

http://www.cars-data.com/en/honda-civic-1.8i-vtec-sport-specs/16858

http://www.cars-data.com/en/toyota-avensis-2.0-16v-vvt-i-d4-linea-luna-specs/47525

The 6 speed Celica has even lower gearing: http://www.cars-data.com/en/toyota-celica-1.8-vvt-i-specs/48071

The Avensis has the same top gear rpm/speed as the Celica: http://www.cars-data.com/en/toyota-avensis-1.8-16v-vvt-i-linea-terra-specs/47517

The final drive would need to be raised, and first gear lowered. 

Wait, that is close to what is in my Mk3!

All the 1.8 engine cars are lower geared compared to 2 litre 5 speed.

[Pingman21]

Starting to wonder if I should just upgrade to a mk3!

It's a shame as I really like my Mk2, but it really does feel like a 6th would suit it so well, I do tend to like low rpm driving though, hardly ever rev high in any of the gears, I just change up all the time, just drop down a gear to overtake etc

[Konrad C]

Iain, your engine is not a diesel, but you are driving it like one going by your latest response!

You have what I used to have, rev conscious. For me, I changed from a longer geared Vauxhall Cavalier, and thought the Avensis was a bit revvy on the motorway. Then I read up on the leanburn engine, and found that it run on a light throttle at higher revs. The fuel economy surprised me. I was getting 40 mpg! Once I got accustomed to the Mk1, I loved it. I loved the 5th gear acceleration and the flexible engine.

With my Mk3, I wish I had the Multidrive version. The Valvematic only comes alive at higher revs and is flexible from 2000 rpm. Once at 4000 rpm, the car really goes, but I hardly go that high. Now I went up Bluebell Hill from M20 to M2, and 6th gear was of no use! 

If you went back to back with your car and mine, then you would agree. 

Treat high speed for high revs. 

   

 

[Pingman21]

Would rather have the longer ratio for cruising and then just drop down a gear if/when I need to, car seems to use allot of fuel when maintaining 80, only getting high 30s where as if I drop the speed/revs down I get much more, pretty sure it could happily maintain 80 and return much better economy with lower revs.