How big can I go ?

[JEFF4507]

Hey,

I have just got my DCI and am going to start working on it soon. I don't want to play with the final drive if I can get away with it, and was planning on getting new wheels anyway. Looking at OZ Superturismo GTs in White, on the Nautical blue clio I think they would look rather suave.

I'll get the 16s so the question is, how big a tyre can I get away with to increase the top speed, 195/55 be ok ? They come with 195/45 R16, and I doubt they'll be much bigger than the stock ones, it's a DCI Dynamique, and I'm not sure, but I think the tyres are 175/55 R15.

Any tips ? As long as I get 120-125 out of it in the end I'll be happy. Have arranged new insurance for exhaust, intake and the alloys, they don't need to know about the ECU as they price the premium increase by a percentage of power increase...

 

[edde]

You'll top out at about 102 on a dci 65 maybe 110 on the 80 (this is realy speed not clock speed) So there no point in bigger tyrs you just don't have the power you'd need about 130hp to get 120hp maybe more power plus you need to stay in the power band which when remapped seems to be about 4k maximum so you'd need very big tyres to get a 10% increase.
Exhaust won't give any extra power same for intake you need more fule and when your have smoky exhaust more air. Depending what version car you have how much you want to push high EGT and risk damage and how much you want to spend depends how much power you can make

 

[JEFF4507]

Hey edde, thanks for the reply.

First, the car is a DCi 80 (though strangley it says DCI 65 on the sticker inside the door).

I was thinking about it today and realise that tyres aren't really the way to go, I will get the 16s with the Lo pro tyres, should be roughly the same diametre if not a cm more than the current 15s.

When enough power is being generated, I will look for a longer final drive, I'm not sure what it is at the moment, however as far as mph per rpm, I would be looking for 30mph per 1k rpm in 5th gear. This will allow for 120mph at peak power, and about 70mph at peak torque.

I know I need an ECU map, more power more speed isn't the case for diesels, and I believe peak power is at 4k rpm anyway, here is a rough idea of the gains.

http://www.superchips.co.uk/curves/cliodci80.pdf

The exhaust and filter/intake are simply to increase air flow, and in turn, the maximum fuel that can be injected. ETG is not an issue on such small cars, maybe if we were talking about a 330d then maybe, but then again, BMW build quality can handle a lot.

If I had to take a guess, I think after the exhaust and intake have been modified to allow for better air flow, then Superchips should be able to whack 110hp out of it. 100hp should be enough to almost hit 120 mph with a longer final drive, though I'll go as far as they feel comfortable, besides, it's still under warranty for a good few years.

 

[Ali]

205-40-16 is the best tyre.

 

[Alan]

I love your face ^^

 

[GordonD]

The rule for increased top speed is a cube rule. Ie, to go 2 times as fast you need 8 times as much horsepower. The chipping company says you will get 17% more power at the same peak power revs. That'll give you just over a 5% increase in top speed. So you want to increase your gearing by about 5% so your new higher peak power will occur at your new higher top speed. Your present wheel and tyre size gives you a 582 mm rolling diameter wheel. A 5% increase on that would bring it up to 611 mm rolling diameter. You would get exactly that with a 205/50x16 tyre which would fit your existing rim.

 

[edde]

There no sticker on the inside of the car showing engine spec besy way to check is to look for an intercooler under the bonnet (the 65 doens't have one) or look at the details on the driver door pillar the 65hp is CB07 (or BB07 if you've a 5 door) the 80hp has the code CB08 (or BB08 if its a 5 door)

 

[edde]

Air filter and exhaust won't make any power on stock mapping.
You need custom mapping to make any more power and then you'll have to decide how far you want to push the injectors but 110hp is about the best you'll get safely.
EGT does mater on any engine 1.0 or 10 liter in size if you start pushing to much fuel and getting smoke then you'll be getting very hot EGT's and in extreme cases burning exhaust valves and melting turbos.
You can blow the turbso on a BWM or Clio its not difficut just open the injecotrs to stupidly wide windows, watch the temps get to 1400~1500 degrees and watch the turbo melt. The reson they don't is mappers don't let them get that hot. To give you an idea mappers get abut 200hp from the VW 150PD engines however with enough mapping you can get 240~250hp as one foreign owner/mapper did but the engine only lasts a few seconds before pulling back power otherwise it will do some serious damage.

Renaults warently doesn't cover mods. If you start letting Superchip make as much power as they can and agree that there reponsibility to there own warently is invlaid then your on your own head Renault have to prove the mod is reponsible but melted exhaust valves and turbos arn't difficult to find when you blow the engine.

 

[JEFF4507]

I'll be looking at a 35-40% increase in power. Air filter (or induction, can't decide, might get both and if the induction is too loud I'll put the filter in) and exhaust will be done next couple of weeks, mapping will be done shortly afterward.

110hp will be easy, and that will be where I'll stop, as I do agree with you edde that too much power will cause problems and in turn, Renault will not deal with it. But I feel this is a fair amount to aim for. It can be called the DCi 110 :clown:

I'll need to get a new sticker :rasp: BTW, it does say CB08 and there is an intercooler, I never really questioned the fact it wasn't an 80. 0-60 is just over 10 secs, have done 115mph (indicated) and that's what it's registered as, I just felt it a bit strange that there would be a sticker on the inside pillar saying.

- Renault -
Model: Clio
Trim: Dynamique
Engine: DCi 65

What am I going to believe ? The registration documents, an intercooler, top speed and acceleration... Or a sticker:star:

A few of you mention 205/50 R16 and that it will fit on my current rim. The rims at the moment are 15s, and the tyres are 185/50 R15. But I am looking at the OZ Superturismo GTs (in white) http://www.oz-alloys.co.uk/product_info.php?cPath=1_20_5300&products_id=1019110 and they come with 195/45 R16 tyres. I'll look into final drive ratios, and if the fitting is outrageous then I'll probably just live with it until I need new tyres, and get some 195/50.

That work ?

 

[Tigger]

looking good what did you get on the RR?

88.1 bhp @ flywheel (whatever that means :S )
139.3 lb/ft torque
127mph top speed

The car is a DCi-80 with a twin backbox and Dragon Performance T-box (www.mrhoot.com)

I'm not dissapointed with the RR but I was hoping for the bhp to be in the 90's :sleepy:

I got in touch with Dragon and told them about the results -
even the guy on the phone was dissappointed :clown: so they are taking the box back to see why it turned out so low

 

[edde]

88.1 bhp @ flywheel (whatever that means :S )
139.3 lb/ft torque
127mph top speed

The car is a DCi-80 with a twin backbox and Dragon Performance T-box (www.mrhoot.com)

Fly wheel is what the manurfactures use for engine hp calims.

For example a 172 is 166UK hp but makes 140 at the wheels (this is the most important bit as it doesn't matter if you make 500hp if the box etc eats up 300hp you've only got 200hp to realy use at the wheels.