2ltr or 2.5ltr WR1 Block?

[JP]

Which is preferred for drag racing/track days?

A lot of tuning firms recommend increasing the capacity to 2.2/2.3/2.5 etc to gain greater torque.....However, the RCM's gobstopper is still running on the 2 ltr block and manages to produce circa 800 bhp (nitrous aided). I understand the engine would still need to be tinkered i.e. forged pistons etc.....

Do I go for the 2.5 or remain at 2ltr on my next mod step?

[marky mark]

Depends purely on your preference, as they all have their pro's and con's. 2.33 is probably the best all round bet as it revs as well as a 2.0 L but you can get 2.5 levels of torque, but it is at a big cost.

The RCM car is so highly developed and away from a road car that it's not really much use as a comparrison.

I personally prefer the 2.0L over the 2.5L as i think the delivery (and in particular the way they hang on at the top end) is more fun but many people prefer the low down punch of a 2.5.

As an 'all round' car, the average driver will certainly probably be a bit quicker on the road in a 2.5, as they are a bit easier to keep on the boil.

Again, you need to have a budget, some figures in your head, what you are going to use it for, then base your decision on this. If money was no object i would do a 2.33 though.

[JP]

I forgot to say Chris B's is based on 2ltr too pushing out big power.

I intend my "1" to be used on the roads not just cooked up in the garage for track days, so need something which will be reliable on the roads.

Thanks anyhow Marky Mark - very useful information.

[marky mark]

I forgot to say Chris B's is based on 2ltr too pushing out big power.

I intend my "1" to be used on the roads not just cooked up in the garage for track days, so need something which will be reliable on the roads.

Thanks anyhow Marky Mark - very useful information.

You are missing the point, there are as many 'big power' 2.0L cars around as there are 2.5L, but they have a quite different feel to them. If you put the right bits in either a 2 or 2.5 they will be reliable.

[dynamix]

i thought you had just built your engine? confused...

2.5 all the way for area under the curves and rapid progress. Who needs to rev the nuts off them when you have 500bhp from 4000 to redline?

[danr55]

having had both I prefer the 2.5 to the 2.0. As Mark says it's all personal preference, you'll get much better torque from a 2.5 though, wont you Dunc!

[JP]

Dynamix - Nope, not started yet but on the cards hence the Qs.

I will be using the car for the drag strips - so i guess I will need quick acceleration.

[The Swede]

having had both I prefer the 2.5 to the 2.0. As Mark says it's all personal preference, you'll get much better torque from a 2.5 though, wont you Dunc!

Maybe you should buy an S-class Merc next time too

2.0 any time. Thought that 2.5 lump was not explosive enough.

[danr55]

having had both I prefer the 2.5 to the 2.0. As Mark says it's all personal preference, you'll get much better torque from a 2.5 though, wont you Dunc!

Maybe you should buy an S-class Merc next time too

2.0 any time. Thought that 2.5 lump was not explosive enough.

he's asking the question "in modded form" as he'll be forging the engine. I'd therefore suggest that a 2.5 would be easier to mod to higher power/torque levels than a forged 2.0

[dynamix]

2.0 any time. Thought that 2.5 lump was not explosive enough.

I think 600 lb/ft counts as explosive enough

RCM's gobstopper is helped considerably by a huge shot of NOS to give it the low down torque. They appreciate and understand that it is torque that matters for pure acceleration.

2.5 with a good turbo = job done

[JP]

2.0 any time. Thought that 2.5 lump was not explosive enough.

I think 600 lb/ft counts as explosive enough

RCM's gobstopper is helped considerably by a huge shot of NOS to give it the low down torque. They appreciate and understand that it is torque that matters for pure acceleration.

2.5 with a good turbo = job done

I guess the 8 injectors will no doubt assist...

[Martynj]

You could always stick to the 2 litre block but use the 2.5 crank, this is the option I have chosen for my own toy.
You retain all of the high revving ability of the 2 litre engine but with the increased torque from the longer stroke.
If you were purely building a road car I would choose the 2.5 every time.