Thinking of buying a 100bhp TDI Astra (SXI DTi)

I'm wondering what the difference in performance will be? I currently drive a 75bhp 6N2.

I know 25bhp isn't a lot, but has anyone driven a 75bhp petrol vs 100bhp diesel and was there a noticeable difference?

Edited 14 February, 201214 yr by bigukg

it will be aye, not by loads but the torque and boost will make it feel like it dude... driving a diesel is completely different tho.

Sounds good to me mate,

How do you mean different to drive?

A diesel only revs to around 4-5rpm therefore your grabbing gears a little quicker. Plus you'll get a small kick from the turbo which can be better. I enjoy driving both to be honest. You'll notice a difference in performance ever so slightly, that being more torque than the petrol 6N2.

If its the Izuzu engined Astra I wouldnt even bother. My mate had one for around 16months and it went through 5 EDU's (EDU's being a ECU but for some reason there called a EDU go figure). A very common fault with them and it was also slow not just for a diesel but just slow.

I found a diesel more boring though, i have a 110bhp tdi golf and a polo GT and still the GT feels quicker, even though on paper the golf is.

The turbo was fun for a week but after that i just started getting bored, just my experience though and everyone is different :)

id say the diesels feel like your going faster, usually cuz of the torque they produce low down in the revs compared to a petrol. but id stick with a petrol unless your after mpg. thats just me though.

As others have said, a very different experience

Astra is bigger for a start- which may counteract any power gain.

A 100bhp diesel isn't going to set your pants on fire though. Low powered diesels fall into two groups - they're either noisy rumbly things that don't rev, or they run a shit load of boost right in the middle of the rev range.

Not driven that particular Astra but I'd expect the latter. A lot of these downsized diesels feel like that. Flat up to 2k, everything in about 750rpm, then the power tails off.

Not that power means everything anyway. Early VAG 2.0 TDI engines were a case in point. The 140PS ones were slower than the 170PS engines but got their peak power more evenly through the revs. In the 170 you'd get nothing till 2k then it'd take off like a rocket, but by 3,500rpm it was dead again.

Very odd sensation tracking them too. You're always trying to keep the needle bang in the middle of the rev range to keep the power up. Not like a petrol where you wring out each gear.

Flat up to 2k, everything in about 750rpm, then the power tails off.

This.

Hate driving diseasels

If you were looking at the 1.4 16v Polo 6n2 with the 100bhp engine, you're looking at an extra 25bhp over what you have.

But you're looking at a completely different car.

For a start, the Ashtray is 25% more powerful - but it's over 25% heavier. So it has a lower power-to-weight ratio and is therefore theoretically slower.

Also, as said by others above, the Polo's n/a petrol engine is more flexible with it's power in use. The Astra uses a turbo diesel, which is limited in overall revs and is even more limited in it's power being in a narrow margin within that rev range.

The Astra is very unlikely to be a quicker car in practice, and you may or may not like it's very different nature.

One thing i do know - the Astra's build quality is inferior. Unless you need the space, i recon it's typically a step backwards.

I'm not overly familiar with either of these two cars but how does torque compare? Surely a better measure of flexibility?

I've driven a couple of diesels (although as a family, we've had loads) and find they're often geared (I.E. Tall) to make allowance for a narrow working range. Certainly, revving them tends to be a fruitless venture.

Actually, one of the diesels was a Mk4 Astra, which was a pool car at work. Talk about lag!

I've just given back a 1.3cdti corsa D 6 speed after using for just over a year for work and putting 20k on the clock. Surpringly nippy car I have to say!

I can confidently say I would much rather drive a car with that engine rather than a lot of dull cars about of a similar capacity in petrol

out of the two i would say an astra, but I would save a little more and get 6n2 gti... 50bhp more and revs!

Edited 13 February, 201214 yr by doug

If its the Izuzu engined Astra I wouldnt even bother. My mate had one for around 16months and it went through 5 EDU's (EDU's being a ECU but for some reason there called a EDU go figure). A very common fault with them and it was also slow not just for a diesel but just slow.

They are common for going yes but if you pop the back off the module, right in the centre of the board there is a solder that melts and breaks contact, very obvious to see its the largest solder on the board right in the centre and its on the side that faces you with rear removed. so just re solder that and there better than new :) then ofcourse just pop the back back on wih a little bit of sealer so it stop water ingress. jobs a good un.

just thought id share :-)

Thanks for your replies all,

The thing I'm looking for really is something more reliable and cheaper to run, the Astra looks like that so far. Of all the reviews I've read the only problem I can see is the EDU. I think the EDU though on these engines is seperate to the ECU? The EDU is a smaller unit connected to the fuel pump isn't it? Not sure on that one!

I'm not expecting the build quality to be up to scratch with a VW to be honest (definitely get what you pay for) and Astra's are only about £1600 - £1800 at the moment. The polo is only worth about £900 part ex though.

I'm not sure what year of Astra I need to be looking at if I want to have it chipped or re-mapped (seen people have had gains from 100bhp to 130bhp), on the 2.0 DTi Ecotec engine.

My older brother has just bought a 1.7 CDTi with an Isuzu engine (75bhp) to run about in for now (he wants a MK5 Golf TDI) and took me out in it last night. It doesn't feel any where near as quick at the bottom of the rev range as my polo which is 75bhp too, but it does improve when the turbo kicks in, so I don't think it's going to be too bad to live with!

The 2.0 DTi has more torque than the Polo too which is reassuring? (230 Nm 169 lb-ft compared to 126 Nm 93 lb-ft)

Don't believe what everyone say about short gears. They may only rev up to 5k, but look at it this way, 60mph in my diesel is about 2000rpm in 5th. In my old mans 2.0 petrol 60mph is about 3000rpm in 5th.

So clearly they are geared longer, thus meaning gear change is the same if not even less frequent in a diesel.

I can go from 25mph to 60mph using only 3rd gear, without making the engine sound like its going to blow up... they are long enough really

(awaits Guy to come on and tell me how wrong I am and comment something about people falling asleep at the wheel...)

Don't believe what everyone say about short gears. They may only rev up to 5k, but look at it this way, 60mph in my diesel is about 2000rpm in 5th. In my old mans 2.0 petrol 60mph is about 3000rpm in 5th.

So clearly they are geared longer, thus meaning gear change is the same if not even less frequent in a diesel.

I can go from 25mph to 60mph using only 3rd gear, without making the engine sound like its going to blow up... they are long enough really

(awaits Guy to come on and tell me how wrong I am and comment something about people falling asleep at the wheel...)

Generally you have to change gear more in diesels due to the tiny rev range where they are actually useable.

And the comment about going from 25-60 in 3rd is irrelevant, my car will do 25-105 in 3rd without sounding like its going to blow up lol.

Don't believe what everyone say about short gears. They may only rev up to 5k, but look at it this way, 60mph in my diesel is about 2000rpm in 5th. In my old mans 2.0 petrol 60mph is about 3000rpm in 5th.

So clearly they are geared longer, thus meaning gear change is the same if not even less frequent in a diesel.

I can go from 25mph to 60mph using only 3rd gear, without making the engine sound like its going to blow up... they are long enough really

(awaits Guy to come on and tell me how wrong I am and comment something about people falling asleep at the wheel...)

Generally you have to change gear more in diesels due to the tiny rev range where they are actually useable.

And the comment about going from 25-60 in 3rd is irrelevant, my car will do 25-105 in 3rd without sounding like its going to blow up lol.

Yep, the wife's MK4 Golf TDi is very long geared, 3.5k rpm at 100mph.

However, i have to change gear far more often in it than in our '99 MK3 valver - the valver will go from 20-100mph comfortably in 4th gear.. Can't do that in the Golf!

Around town the Golf is a fail of two cultures which don't mix - calculated very regular gear changes are necessary in order to shift it about, gears being worked all the time, yet there's no reward in that it's not fun. You put the effort in, but it just doesn't translate into anything but two seconds of boost every time.

The valver is fun in comparison, yet relatively effortless, unlike the Golf i have a choice of gears to select at any given speed, it's got more power either side of the Golf's range and it'll keep accelerating for twice as long if i need it to.

The '09 Vito, The '09 207 and the Golf all the same to drive, all have/had a nice turbo boost between 2-3k but not much anywhere else. It's frustrating, it's actually retarded and feels like a major compromise. Like an electric car or something, it's just not the full picnic. Turbo diesels are crap.

Not driven the exact engine you are looking at but its a completely different driving experience and i find it changes the way i drive massively.

I've got a 1.9tdi Vento for the week and its a real lazy drive. All the gear changes are a piece of piss at pretty much any rev range, forcing 2nd and 3rd while going too slow is easy peasy so you can pretty much drive any gear for any speed. Just my experience but it really has made me drive like an old man.

Although in terms of the things you are swapping for (reliability and economy you say), I've had it for over a year and only changes tyres, bulbs and washer motors (touch wood) and the mpg is a real improvement. Good luck with the choice!

I was driving a 2003 1.9 CDTI astra van for work, the thing was furiously fast to take off, torque was just outbusting, even when loaded up with tools, you could feel the weight but it still took off well, also handled motorway driving very well

Being a van i assume it had more torque to handle the extra weight, i don't think it was a fast car/van it just took off well and maintained it's speed

I don't think it's worth it over the 6n2, the difference isn't as extreme as the 1.9 astra van and if you aren't carrying alot of passengers/tool/weight the extra torque feels like a waste and will make you cringe filling up tbh

What are you after though... extra power/torque or better mpg because as everyone else already said, the two are so different.

dont do it

25bhp when the car already has 300bhp...not very much

25bhp when the car only has 75bhp in the first place...quite a lot! Another 33% power...WOO!

In your case you'll be lucky if the Astra isn't anything other than slower and worse on fuel. It should be a fair bit lardier?

Edited 13 February, 201214 yr by Tav

I've been thinking about this for a while and checking back on replies.

I thought the diesel would be next to nothing on tax, easy to insure, save a bit of money on petrol. It's not looking like it'll be either.

The 6N2 is fine, but it's just not quick enough, so I thought "I'll get a diesel with a bit more power, that way, I've got a faster car that's also cheaper to run".

I'm looking at Golf GTi's now. I know this being a Polo forum you'll all say "Get a Polo! They're 125bhp and lighter!" but I just can't justify it on insurance, and I can't even really justify a new car for the sake of buying a car that's practically the same only much faster.

I did look a Golf GT TDi's but 1) not keen on the diesel idea now (especially after reading they're no where near as fun to drive and can be gutless) and 2) there aren't many about so when it comes to shopping it'll take ages to find a good'un!

Hoping to buy trade and part ex the Polo, there's a good few Golf GTi's about for under a grand! Part ex my car for about £800 and shove £1,100 cash and should be able to buy one at the end of March all being well.....then I'll just have to sort out insurance :(

Would any of you get a 2.0 Bora Sport over a Mk4 Golf 2.0 GTi? Sorry - off topic slightly now!

the 2.0 bora and 2.0 golf will be the slowest cars ever to drive. You'll be very disapointed! I have a pd130 and its been mapped and its got 165bhp and 300lb ft torque and its the quickest car i have driven. And I've had quite a few little hot hatches from corsa gsi's to the polo GTi the polo GTi being the best handling one probably due to coilovers but the ibiza i have now is by far the best to put a smile on on face. I used to swear by petrol but now having his engine i get the best of both worlds being power and big mpg's!

For me though, going from a 75bhp Polo, I don't think a 115bhp 2.0 Golf/Bora would be too slow?

I do now think a 100bhp turbo diesel Astra would be.

Insurance is a fooking joke though!

yeah but a 115bhp bora that weighs about 2 tonne will be alot slower than a 1 tonne polo. its all about power to weight and how the power is delivered