Is displacement better?

[Noz]

I know displacement gives better torque curves, but what's really the benefit over higher displacement engines.

 

I'd love a 1uz. There was a 6 litre hummer engined R32 at a local event drifting on the weekend, just got me thinking about a 1uz again.

 

Considering people have taken the 2JZ to great leaps, even the NA block has done 900hp in the US (and 600 on this forum) it just makes me think, what is the real benefit of two equally powered engines with different displacements.

 

Is it just that lower down grunt that's preferred?

[Guigsy]

Iv driven a vette and bpu supra. Both auto both arround the 400 bhp mark. I forget what size engine the vette had. 5.something I guess. But the difference in acceleration was distinct. The vette blew me away. Off the line with a slight poke of the accelerator snapped your neck back. The supra didnt do that. But is guess they are not that different speed wise

[JamieP]

Depends on the engine, short stroke or square seem to be the best engines, 2jz is a square engine and is pretty good, 86mm bore and stroke, soon as you go long stroke (3.4L) the engine is under more stress and don't like to rev so well.

 

My GTR is a short stroke 95.5 bore and 84mm stroke, loves to rev.

[Ian C]

Turbochargers just make smaller displacement engines behave like larger ones. Larger displacement NA engines have better low down response than smaller boosted engines because they have no boost threshold getting in the way of acting like a large displacement engine. Also, they can run at higher compression ratios which gives more power - although I think modern boosted engines are pushing that envelope quite a way these days.

 

The big NA engine instanto throttle response is the result of this. It'll feel much more responsive and turbo power tends to ease in due to the turbo lag as well, making it feel less aggressive.

[Gaz6002]

Basically it's all to do with versatility. Turbochargers make an engine more efficient, but at the expense of throttle response as you have to wait for the turbine to get up to speed. A bigger engine will be less efficient in terms of the power it makes, but that power will be available quicker and over more of the rev range.

[Noz]

Depends on the engine, short stroke or square seem to be the best engines, 2jz is a square engine and is pretty good, 86mm bore and stroke, soon as you go long stroke (3.4L) the engine is under more stress and don't like to rev so well.

 

My GTR is a short stroke 95.5 bore and 84mm stroke, loves to rev.

 

I suppose the inertia is less on a short stroked engine making more sense. Would you ever consider stroking it?

 

If you had a large displacement engine, would it be assumed you would get more lower end power but less top end then?

 

Turbochargers just make smaller displacement engines behave like larger ones. Larger displacement NA engines have better low down response than smaller boosted engines because they have no boost threshold getting in the way of acting like a large displacement engine. Also, they can run at higher compression ratios which gives more power - although I think modern boosted engines are pushing that envelope quite a way these days.

 

The big NA engine instanto throttle response is the result of this. It'll feel much more responsive and turbo power tends to ease in due to the turbo lag as well, making it feel less aggressive.

 

I've always found with a T61 turbo the kick of boost makes it feel faster. I drove an M3 with the same power, and that felt slower because the delivery was much more linear. So really displacement is just used for lower end power. Turbo converting a 1uz would give the best of both worlds?

[Herb]

I'll take your NA-T parts, Noz...

[Lee P]

It all depends on what the engine was designed for as well.

 

The 1UZ was designed for fuel economy so makes a lot of its torque low down but cant rev very high as the head is very restrictive.

[JamieP]

I suppose the inertia is less on a short stroked engine making more sense. Would you ever consider stroking it?

 

I'd not bother on the GTR, it's a 3.8 already and has plenty of low down power, I'd rather have stock stroke and a reliable car.

[Rob_Mitchell]

As above, i was going to go 3.4l but it just carries that added stress on the rest of the engine. A quality built engine is still the way to go i think and some members cars prove they can take the power

[Digsy]

It used to be true that there was "no replacement for displacement" but its not any more. There's been a huge amount of development into reducing turbo lag which has been driven by the current trend in downsized engines. Now even tiny engines like the 3-cyl Ford Fox have torque curves that look like billiard tables.

 

The thing about bolting a huge single turbo to an old engine like the 1JZ or 2JZ or pretty much anything else to get a truly biblical peak power figure is that its never going to be properly matched for low down performance, so having a larger engine will get you a throttle response that feels more "in keeping" with the top end, but its kind of defeating the object and the opposite way to the way that OEMs are going.

 

The next step as we move towards the next big emissions target in 2020 will be more gasoline engines like the VW twincharger, or the dual boosted much like the diesels that are starting to come onto the market (take the BMW triple turbo as an extreme example). Then you will have small displacement engines with optimised boosting across the whole rev range. The downside is that mapping the control system is a nightmare and probably beyond what is possible using anything other than a "proper" factory ECU. A company like Bosch will take a year to fully map a modern pressure charged port fuelled engine and you can double that once you start hanging the cutting edge gizmos on it.

[Kaan W]

The reason I'm building a stroked motor is cause I have an auto and I would like to pull away from the lights quicker. Not going for much more power than I already have but I want the power there throughout the rev range.

[Noz]

I'll take your NA-T parts, Noz...

 

I think the mrs want's them for her E30 conversion. Fight her for them, and provide me with female services and they are yours my friend! :

 

It all depends on what the engine was designed for as well.

 

The 1UZ was designed for fuel economy so makes a lot of its torque low down but cant rev very high as the head is very restrictive.

 

I did read about the alloy head and block. Do you think 1000hp would be suitable on a 1uz?

 

I'd not bother on the GTR, it's a 3.8 already and has plenty of low down power, I'd rather have stock stroke and a reliable car.

 

3.8 would be awesome. Does the lower end feel more responsive like a large displacement engine, or does it drive like a boosted motor?

 

The reason I'm building a stroked motor is cause I have an auto and I would like to pull away from the lights quicker. Not going for much more power than I already have but I want the power there throughout the rev range.

 

Wouldn't it be better to have a sequential setup, like the staggered twin setup you can buy. Think it's boostlogic. Could be wrong there

[Nic]

The reason I'm building a stroked motor is cause I have an auto and I would like to pull away from the lights quicker. Not going for much more power than I already have but I want the power there throughout the rev range.

 

What cams do you currently have fitted? no mention of them in your garage spec.

[Kaan W]

What cams do you have fitted? no mention of them in your garage spec.

 

Stock UK cams on that engine but the new engine has hks 272s.

 

Noz, ive not looked into that setup but if boost comes on the same as a stroked engine it sounds like a nice bit of kit.

Edited July 24, 2013 by Kaan W (see edit history)

[Nic]

It used to be true that there was "no replacement for displacement" but its not any more. There's been a huge amount of development into reducing turbo lag which has been driven by the current trend in downsized engines. Now even tiny engines like the 3-cyl Ford Fox have torque curves that look like billiard tables.

 

It'll be interesting to see what forced induction developments emerge from the F1 engine changes next year. The engine suppliers must have a lot of top secret turbo development work on the go at the moment which could revolutionise the OEM market.