explanation of the "lower" power of 2.4t to the 1.9t

**s40t** · Wednesday 18th February 2015, 21:01

This subject has been bugging me since interest arose. How does the 2.4 has less power with at extra half a litre of engine? Is it emissions based? A more aggressive ecu/ compression ratio. It just doesnt make sense and cant find anything anywhere. I its like comparing jam to marmalarde?! How and why lol

**claymore** · Wednesday 18th February 2015, 21:27

Are you talking about a 1.9 in the T4?

**s40t** · Wednesday 18th February 2015, 21:57

Originally Posted by claymore

Are you talking about a 1.9 in the T4?

I am indeed bud

**jamesy12345** · Thursday 19th February 2015, 05:24

it's just down to the set up from factory, fella...bigger displacement doesn't automatically more power. Maybe more potential for power from the bigger engine (on a DIY budget anyway). Probably the 2.4t is lower boost. Look at the old rover NA V8s they had 180 hp or similar from 3.9/4 litres..and the 80's formula 1 turbo engines put out 1000+ hp from a 1.5 litre

It's not how big it is, it's what you do with it!

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**mitchyboy01** · Thursday 19th February 2015, 07:41

The 1855cc 1.9 T4 is based on the 2319cc 2.3 T5 just with a cylinder chopped off. It is exactly 80% of the capacity of the 2.3 T5. These motors are low compression with high boost. The lesser 2.4T (non T5) makes less power because it uses less boost due to a higher compression ratio and small turbocharger.

The later 2.4 T5 is a different animal and makes 260bhp from the factory due to lowish compression and a larger K24 turbo.

**MaxTS** · Thursday 19th February 2015, 07:56

It was a deliberate design as well as the x40's also had the 2.0T again a larger CC but smaller pressure resulting in lower peak BHP but a nice smooth all round engine.
Am I correct in saying that the both HPT versions are just the LPT block with reinforced liners?

**claymore** · Thursday 19th February 2015, 07:59

Originally Posted by MaxTS

It was a deliberate design as well as the x40's also had the 2.0T again a larger CC but smaller pressure resulting in lower peak BHP but a nice smooth all round engine.
Am I correct in saying that the both HPT versions are just the LPT block with reinforced liners?

No, the only difference is the compression ratio.

**s40t** · Thursday 19th February 2015, 13:16

Beautiful stuff. So as probably mentioned previously, theres no littke hidden restrictors dotted around ibtake side etx just down to design. May have to look into bumping the gasket up and winding the boost up in the future. Found a site which sells a mte pcc, cat back, Induction air filter and a remap for £950... what we reckon? Site says 241bhp whuch I thinks respectable at stage one with the lighter supporting modifications

**960kg** · Thursday 19th February 2015, 18:00

^^^^^^^^^^^^^^
All the above accepted.......but at the end of the day there is NO substitute for Cubic Capacity.........if the 2.4T engine was in the X40 as the 2.0litre T4 is then the car would probably be a much better motor to drive!

**mitchyboy01** · Thursday 19th February 2015, 20:07

**960kg** · Friday 20th February 2015, 14:07

Whatever one uses to get more power from an engine be it turbos, larger valves, cam timing etc. etc. when applied to a larger engine ...Bigger is Better!

The larger capacity in itself gives more vacuum to allow more air/fuel to be burnt resulting in more power.

Yes, small turbo engine can give good torque figures but can only be used higher up in the rev. band!....low down grunt is very limited....

As an example my 3.2 v6 gives 510Nm with a 7 gear box and can all be used from 1600 revs!...

**T5frankie** · Friday 20th February 2015, 14:15

Originally Posted by 960kg

Whatever one uses to get more power from an engine be it turbos, larger valves, cam timing etc. etc. when applied to a larger engine ...Bigger is Better!

The larger capacity in itself gives more vacuum to allow more air/fuel to be burnt resulting in more power.

Yes, small turbo engine can give good torque figures but can only be used higher up in the rev. band!....low down grunt is very limited....

As an example my 3.2 v6 gives 510Nm with a 7 gear box and can all be used from 1600 revs!...

best get it mapped then if that's all it's got lol

**960kg** · Friday 20th February 2015, 14:31

That is still the next move but there is a 710Nm limit on the auto box for my C class model!

**mitchyboy01** · Friday 20th February 2015, 18:14

You are talking diesels now vs petrol? Totally different discussion to be had there.

Also your diesel will run out of puff 2.5k before a decent petrol lump. The A200 AMG is a 360bhp 2.0 Turbo. How would your car fare against that?

The Americans have proved with their NA 5.0 V8's making only 250bhp and 12mpg. There is definitely a replacement for displacement.

**merc85** · Friday 20th February 2015, 18:27

Originally Posted by mitchyboy01

You are talking diesels now vs petrol? Totally different discussion to be had there.

Also your diesel will run out of puff 2.5k before a decent petrol lump. The A200 AMG is a 360bhp 2.0 Turbo. How would your car fare against that?

The Americans have proved with their NA 5.0 V8's making only 250bhp and 12mpg. There is definitely a replacement for displacement.

No good comparing Petrol vs diesel Power as the delivery is totally different, in a fix gear of similar ratio and similar weight of car the car with the greater torque id imagine the derv would pull ahead until the the petrol car reaches its power band usually higher up the rpm. eventually the petrol car would have the legs on the derv id have thought.

A smaller engine with a turbo will have a shorter life than a bigger engine if the too engines put out a similar power as the larger engine is not as stressed.

Thats not to say the larger engine is as fuel efficient cus it wont be but it will be easier/smoother drive as it wont need to rev to create its power.

At least thats how i understand it.

And of course a A200 turbo will quicker overal, its lighter for a start and have more power but will need to rev which takes time so over a given distance it may not be as fair ahead as you'd expect not from a mapped c320 cdi in anycase.

Not out to dis anyones view and maybe wrong but its how i understand and have been told in the past.

**s40t** · Sunday 22nd February 2015, 02:55

See I disagree with the fuel consumption part. My c70 is actually better on fuel than the t4 was.its all about power delivery. The t4 despite having a small advantage over the c70, it had a much more aggressive boost delivery. The c70 almost spreads from 2.5k up to 5.8k then backs off.. I guess the nature of it being a luxury cruiser benefits this style. Either way. Roll on remap

**960kg** · Thursday 19th March 2015, 16:17

Originally Posted by 960kg

Whatever one uses to get more power from an engine be it turbos, larger valves, cam timing etc. etc. when applied to a larger engine ...Bigger is Better!

The larger capacity in itself gives more vacuum to allow more air/fuel to be burnt resulting in more power.

Yes, small turbo engine can give good torque figures but can only be used higher up in the rev. band!....low down grunt is very limited....

As an example my 3.2 v6 gives 510Nm with a 7 gear box and can all be used from 1600 revs!...

Originally Posted by T5frankie

best get it mapped then if that's all it's got lol

At last just got the C class remapped via the ECU not tuning box.....+66bhp to 290 and the torque has risen from 510 to 628Nm........all luckily controlled by RWD and the auto 7g box...

....and 40+ to the gallon!