[E9xfan89]

basically I'm in a bit of a predicament at the minute where I'm only doing 10 miles a day in my remapped 330d - I need a petrol but don't want the running cost issues of a 335i. I've been looking into a 330i and was just curious how this would compare to a mapped 330d?? I'd get the 330i mapped for what's it's worth maybe 10bhp and 10lbs ft torque?

Anyway my original question, in trying to work out the performance difference I've been looking at the horsepower per tonne for each engine.

I have attached a picture of my workings but if it does work here's a rough guide.

Gearbox would be a manual.

330i mapped - original 0-60 was 6 seconds mapped hp = 282 and mapped torque = 250 lbs ft. That means about 192 horse power per tonne and 170lbs ft of torque per tonne.

330d mapped - original 0-60 was 6.6 seconds mapped hp = 300 and mapped toque = 400 lbs ft. That means about 197 horse power per tonne and 273 lbs fr of torque per tonne.

In comparison a 335i has a 0-60 time of 5.5 seconds, standard hp = 306 and torque = 295. So that's 200 horse power per tonne and 194lbs ft of torque per tonne.

So what does this mean? How does horsepower per tonne translate to real world performance? As I'm comparing the same chassis would it be safe to say a mapped 330d with 197 hp per tonne would have the same/very close 0-60 time as a 335i with 200 hp per tonne??

Thanks for any help

[Sparky68]

You are basing it on outright figures and not through the rev range.

[djgandy]

You probably need ratios and differential numbers too before you can guess at 0-60 times.

But yeah, a 300hp 330d will be around that of a stock 335, assuming the stock power is as listed ;-)

[AWSAWS]

I would think that a normally driven 335i (Urban and highway combined) would be just as efficient as a 330i for MPGs. Only when lead footing it would it be different but with the 100 to 150hp potential of the tuned 335i being the benefit.

If lead footing a 330D and 330i then I bet they cost about the same to run as well once fuel costs and MPGs are considered.

You'd want to be considering gear ratios and final drive for true performance figures above.

[AlanYoro35i]

A normal driving 335i will return better mpg than a 330i!!

[Aragorn30d]

The basic answer is "quite closely" but it depends what your doing. If one car has 195hp/ton and the other has 192 or 199, its too close to call as it depends on many factors, including the squidgey bit behind the wheel, but essentially they'd be more or less a dead heat.

Both cars flat out, the car with the highest bhp/ton will be faster, if theres a reasonable gap between them. It also depends on the cars. If you take two cars, one with 200hp and weighing 1 tonne, then another with 300hp weighing 1.5 tonnes, you'll find that low down they'll be pretty much identical, however once you get up the speed range a bit and are heading towards triple digits, the more powerful car will start to pull away due to aerodynamic drag. If you require 100hp to overcome the drag, one car only has 100hp left to accellerate with, whereas the other car still has 200hp left.

Diesels v petrols also muddy the waters, because a mapped 330d for instance will make that 300hp more or less continuously from 3000 to 4500rpm (say), whereas the 330i figure will be a peak only. That means the diesel is producing the 196hp/ton continuously while accellerating, whereas the petrol one will be dipping down and then rising again as the car accellerates through the rev range. Thus the diesel could be the faster car even if it had less on paper.

I would recon a 330i, driven hard, would probably be a little bit slower than a 330d with a good remap but not masses of difference, but it would also feel VERY different to drive. The 330d is going to feel very torquey, with gobs of power available everywhere in the rev range. The 330i will need revved to unveil its power, which will probably make it feel significantly slower day to day driving lazily, but will also probably feel more powerful when pressing on due to the way the power builds up.

As an example of this, a mapped 330d has ~200hp available at 2000rpm, and ~260hp available by 2500rpm. A 330i cruises at higher RPM's due to the longer gearing, but even at 3000rpm it only has ~150hp, needs to get to 4000rpm to achieve 200hp, and doesnt get to 260hp until over 5000rpm.

[Dann]

I wouldn't get hung up on -060 anyway. It's a pointless measure.

Look at the 30-50, 30-75 and 50-75

[djgandy]

Originally Posted by AWSAWS

I would think that a normally driven 335i (Urban and highway combined) would be just as efficient as a 330i for MPGs. Only when lead footing it would it be different but with the 100 to 150hp potential of the tuned 335i being the benefit.

If lead footing a 330D and 330i then I bet they cost about the same to run as well once fuel costs and MPGs are considered.

You'd want to be considering gear ratios and final drive for true performance figures above.

Originally Posted by Yoro35i

A normal driving 335i will return better mpg than a 330i!!

I think OP is more worried about parts/repair/servicing than MPG as he only does 10 miles per day.

[AWSAWS]

Originally Posted by djgandy

I think OP is more worried about parts/repair/servicing than MPG as he only does 10 miles per day.

Would u think parts for 330i are much cheaper than for a 335i?

I imagine just the purchase price of the car itself is prohibitive. After that I doubt there's much in it.

My last round trip to Heathrow. I have a lot of mods and trust me. Most traffic is disappearing in my rear view.

[ahmedb]

I'd also factor in engine sound, revvability (if that's a word) and a bit more onus on torque.

With a mapped 330d, you could put your foot down when cruising and there will instantly be power. With the 330i, you would need to put the manual box to more use to make the most of the available power as peak bhp with petrol engines tends to be at the higher range of rpm whereas diesels tend to be mid-range depending on the map.

If you aren't thinking about getting the dpf removed, this could potentially be a concern too unless if you get a decent bit of road to release the soot.

Would there be much difference with servicing/maintain a diesel compared to a petrol?

[mob17]

We had a big discussion on this a few months back.

Conclusion was its all about the area under the curve, and gear ratios etc. i think doughboy was going to make a speadsheet up incorporating everything.

[AWSAWS]

The small twin turbos on the 35i make the pickup(spool up) very rapid. Peak torque is from 1200rpm. It actually feels alot like a diesel but revs far higher. The torque is also very linear. It just accelerates at a constant rate. It lunges less than a diesel and actually feels slower because of the constant torque in my experience.

[djgandy]

Originally Posted by AWSAWS

Would u think parts for 330i are much cheaper than for a 335i?

I imagine just the purchase price of the car itself is prohibitive. After that I doubt there's much in it.

My last round trip to Heathrow. I have a lot of mods and trust me. Most traffic is disappearing in my rear view.

Well the cost of replacing two turbos on a 330i is £0.
Then there is HPFP
Injectors and coils which are quite common on 335.

If you don't get any of those costs, its fine. But no one really wants a £2k bill for a car they perhaps only want a little fun out of.

[Digitalize]

The only one you'll probably really notice is torque difference, in real world use.

[AWSAWS]

Originally Posted by djgandy

Well the cost of replacing two turbos on a 330i is £0.
Then there is HPFP
Injectors and coils which are quite common on 335.

If you don't get any of those costs, its fine. But no one really wants a £2k bill for a car they perhaps only want a little fun out of.

I doubt these things are as common as people make it sound.

Coils are £25. If going for the 330i, i'm sure it has similar ones.
I think a HPFP is somewhere around £250 for the part
You can always get a warranty for piece of mind.
All cars break eventually. How much for a dpf if you stick on a diesel!
The turbos don't just pop. I run mine at 20psi, where stock is 8psi.

[Rich_D]

Originally Posted by Digitalize

The only one you'll probably really notice is torque difference, in real world use.

This ^

[E9xfan89]

Thanks for all of the replies guys very useful.

It's sounds like a 330i wouldn't feel as quick in the real world as my mapped 330d - which is a shame as the 330i was an ideal option..

I really would love a 335i and fuel costs wouldn't bother me but the age and mileage I'd be looking at I doubt I'd get a warranty. The repair costs of 2 turbos when they inevitibly develop waste gate rattle and the hpfp failing really puts me off

[Kerr]

If you're worried about running costs due to problems, don't buy a diesel for doing 10 miles a day.

[E9xfan89]

Originally Posted by Kerr

If you're worried about running costs due to problems, don't buy a diesel for doing 10 miles a day.

Where did I mention I bought a diesel to do 10 miles a day? Circumstances change, I've just got a new job closer to home. My previous commute was 70 miles a day.

[AzRiz]

If engine/exhaust note matters to you at all, I would urge you to get a petrol over a diesel.

I have a 330d LCI on standard map at the moment and find it great to drive. The DPF delete and remap I'm planning next year will make it even more awesome. I'm coming from a race-mapped 300bhp Golf MK4 that popped and flamed, and had launch control like gunshots lol.

However, I have only one complaint about my E92. I'm really missing a decent exhaust note that only the petrol versions can supply. I currently have straight-pipes post-DPF and it sounds pretty rubbish compared to a half-decent petrol, and although the DPF delete will really open it up, I still am not a fan of diesel noise in comparison to petrol and this is literally the only negative that I can say about my car. If it was a 335i I definitely wouldn't be planning to sell it in a couple of years like I am.

Need some yummy petrol noise back in my life...

If the exhaust note doesn't matter to you, the 6-pot diesels are great and sound very refined so no worries there.

[nicktyler]

Originally Posted by AWSAWS

The small twin turbos on the 35i make the pickup(spool up) very rapid. Peak torque is from 1200rpm. It actually feels alot like a diesel but revs far higher. The torque is also very linear. It just accelerates at a constant rate. It lunges less than a diesel and actually feels slower because of the constant torque in my experience.

Couple of bolt-ons, a decent map and you will feel the lunge at any rpm

[AWSAWS]

Originally Posted by nicktyler

Couple of bolt-ons, a decent map and you will feel the lunge at any rpm

I think it's because I'm DCT. I just don't feel any lunging.

Don't get me wrong, the car is fast!

I trapped the quarter mile at 117mph where the new stock M4 gets around 119mph.