140bhp n/a vs 160bhp turbo
Turbo Mini Forums

Im thinking about building a turbo engine in the next week or so, instead of bothering my long stroke motor, I was just trying to work out how fast turbo minis actually are.
If I build a n/a engine I'd try and squeze 140bhp out of it but if I built a turbo engine I'd aim for about 160bhp or what ever usable power I could get. Which do you think would be faster, not just 0-60 or top speed but around the nurburgring. I'd use a 3.1 diff with the turbo or a 3.4 or 3.7 with the n/a engine. I know it's a bit of a daft question but I really don't know which direction to take, the only thing that's really putting me off a turbo is I haven't had enough time to research it because up until about yesterday I was 100% set in stone on a 1430. I'm about 50/50 now so I'm in a right mess because I need to get the machine work rolling this week!

It would be much easier to get 160bhp out of a turbo lump than it would be to get 140bhp out of an NA lump.

If something is worth doing, it's worth doing half of.

If it's going to be used on the road, I would strongly advise the turbo route. I currently have a 130bhp 1380 n/a that is very quick, but requires high revs to pull the power. At 70mph it's at 6k. It sounds great but it not practical in every day traffic or on the motorway. Plus it requires regular rebuilds. I'm moving to turbo because I long for more torque at low revs and a peaceful and relaxing drive. Just for the track the n/a will be more trackable and quicker. 140bhp n/a is quite a feat, using an 5 port head even at 1430-1460. Wots is your planned spec?

Class C 3rd Place Avon 2011 14.18 @101mph

I know it will be easier getting the power from a turbo then n/a but for me it will be less of a challenge, as turbo would be hard for me to do I think. Was obviously gonna use a S/C box with drops and X-pin. Then 1380 turbo or use my MED long stroke crank and make it 1430, or maybe 1430 turbo but I'd be using a 2" maniflow system, weber 45 on decent inlet, 38mm chokes. Head is a MED rally head but it wont make anywhere near 140bhp with that head so I'd need a better one. Becuase it's a long stroke I wouldn't want to rev it past 8k so I'd be using a kent 296 which I'm not sure is enough for 140bhp. I know it wouldn't make 140bhp at first but it's what I'd aim for when tweaking it etc. It's hard for me to choose because I've only ever seen these mad a-series engines from outside. I like the sound of turbo on youtube but I also like the sound of weber

the NA high rev machine will guzzle fuel, especially with a webber. my friend had a 130bhp webber powered beast and it returned a nice 8mpg.

However i am actually seeing 133lbps of torque and 140ish bhp from my turbo and its getting approx 35mpg with a bit of welly too. its running 9psi.

Also if you turbo, you dont need big CCs. go for 1275 (if possible) 1293 or 1310.

Edited by Johnny on 12th Apr, 2011.

hmm mpg was another factor

Sorry to hijack with a question, but why if possible a 1275 and not a 1293 or larger?

Go turbo.

trust me ive been down this road.

Dan, am only 15mins from Nottingham, your welcome to come around and I'll take you out, to witness the noise and compromises you will have to make for big power from a n/a.

Class C 3rd Place Avon 2011 14.18 @101mph

oooo I might take you up on that alaskanow0! Will PM you

The reason for going 1380 turbo is I have some 73.5mm pistons that are good for turbo imo, ideally I'd have forged +20 omegas for a turbo engine but I need to be careful how I spend my money because when it comes to building engines it soon gets spent

I'm in such a mess as to what to do, I'm seriously considering building 2 engines lmao

as i said earlier...

turbo!

There are only a handful of 140+ n/a engines about and it requires a 310 cam with the best head available. It wont work with a 3.4 diff - you'll need a 3.9 to make it driveable and a lightweight car

I seriously doubt it!

........and consequently it will be shite around the Nurburgring. To do a 10 min lap requires an AVERAGE speed of 78mph. With a car with maybe a TOP speed of 105mph this is a tall order.
I've been round in 9min 4sec, but touching 130mph in places.

turbo. i had to make this choice too. my friend has a 135bhp na and it cost him more than my 180bhp turbo. plus turbos sounds cool and are fun to drive. alot more drivable everyday and you can use a longer final drive which will be better for the ring. the ring isnt really a track id choice a mini for though to be honest. just go turbo. if anything they are less confusing and easyier to build than a very high powered n/a :) hope it helps

Torque. Go turbo.

ONCE you go turbo You Never GO BACK!

Seriously though, what answer do you think you would get on this forum?

he had obviously already made up his mind!

On 13th Apr, 2011 apbellamy said:
Seriously though, what answer do you think you would get on this forum?

That 20 hp difference is probably around 75 lbft in the most used rev range.

For a road car, turbo all the way.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

For road use I would go cast pistons, reliable and alot cheaper.

Just been in alaskanow0's 130bhp mini and it's abslutely immence, realisticly I think I can tame down the cam and have a 3.4 diff and it will be plenty for now. It was a silly question on a TURBO mini forum lol. But it has helped me as I wouldn't of been able to do in such a immence car lol. I've driven a megane RS with about 225bhp and the adreniline from that was less than what I got from just being a passenger in this beast.

Edited by danrock101 on 13th Apr, 2011.

Drove a the Megane at Brands...actually quite impressed considering its a Renault!