sod BHP, what about torque !!

[Andy92 0]

Im fed up to be honest with all BHP mods, im not bothered about top speed that much, the speed that bothers me is 20 --> 70.

 

So what are the best torque mods ? i appreciate that by increasing BHP a lot will affect torque, but thats not increasing it propley more of a side affect!

 

So what do people know? top 5 torque mods ?

[Henny 0]

YAY! someone who's in my school of thought for tuning... 8)

 

Torque is well helped by balancing the input and output pressures... If the gasses can get into the engine nice and cool and quickly, and then the burnt waste get out as easily, you'll get some nice increases (hence gas-flowing and porting)...

 

Capacity helps (size IS important! ;) ) and having a nicely balanced, lightened and setup bottom end is helpful too.... 8)

 

How far are you willing to go to get your torque? Getting high BHP figures is easy, just sling a small pulley onto a G60 and rev the life outta it will do that... but it'll cost you when the bottom end bearings and supercharger give up 'cos they've not been spec'ed for that kinda punishment.... :roll: (there's a couple of members here who are finding that out at the moment! :? )

 

Torque from idle up to a decent redline needs a series of well planned mods, some of which include gearbox mods to make sure that your box ratios match the power band of your engine... ;)

 

As for top 5 mods? I dunno.... I set out on my project with the specific aim of stump-pulling torque from WAY low down on the rev counter, so I've lost count of the mods I've done to get this achieved.... ;) Having the map written for torque not BHP figures helps a lot (ask H100VW, or G-man who's just bought his old G60 golf) ;)

 

Hope this helps, although it doesn't actually entirely answering the question you asked... :?

 

Keep an eye out on my members gallery to see if my plan pays off and I get the torque curves I want once my new engine is bedded in.. 8)

[Andy92 0]

Gosh thats a lot of smileys !! :D

 

I am willing to put the work in no problem, but money will be a challenge. My budget will be £2000 (my car has about 3-4 weeks then it wont run anymore, it for longer than it was supposed to so...) and im thinking about a jetta with a new/conditioned engine put in (will even consider a g40 or g60 :D doubt i could afford it though !). Also the Jetta is about £800 leaving me over 1g to spend on the gorgeous VW engine :D

 

So... port & polish, gearbox, skimmed head ? higher compression but is that BHP or Torque ? need to read up on toque more tbh.

 

How do you setup the bottom end ? one thing ive never know !

 

Any URL's appreciated, love to read this stuff !!

PS cant wait to see the power curve !!!

[Dubcharged 0]

Hi Guys

 

Here's a great explanation of BHP and Torque and their implications. Good reading!!!

 

 

http://www.ls2.com/boggs/handt.htm

[GazzaG60 0]

A g60 isn't ever gonna make good HP figures.

 

1. it doesn't rev enough and stillk make power(poor 8v head)

2. its got a Glader on it that wont wanna rev past 6krpm with a decent size pulley.

 

Good low down torque can be got from a small pulley. itll get the charger pumping sooner. im runnig a 65mm that does the trick. i cant rev past 6k but the engine in standard form drops off at around 5500 anyway.

 

problems that you get from this type of mod.

 

1. traction-low down torque gives wheelspin.

2. belt slip. mine aint too bad but if you wanna get rid of it go for the toothed pulley like henny has.

[Henny 0]

Hi Guys

 

Here's a great explanation of BHP and Torque and their implications. Good reading!!!

 

 

http://www.ls2.com/boggs/handt.htm

 

Just read that document... Very enlightening.... 8)

 

There's some really good comparisons and mental imagary used, I'd recommend that people read it...

 

Thanks for posting that... 8)

[Andy92 0]

well that took me almost an hour to read and understand, but it was worth it!!! i think lol Very well written just too many numbers.

 

Glad i understand it more, great post DubCharged !!!!

[beavis 0]

Torque!!!!!!!!!! ye.. we love it. Thats what we are looking to achive out of our new engines rebuilds. Huge BHP figures do not interest me at all. Many people who aim for the big BHP figures end up with a car that is gutless midrange, but has a surge of power in the last 1000 rpm of the rev range from 5000-6000 rpm. A car with 30bhp less but with a strong flat torque curve would be off up the road before the big BHP monster had kicked in.

The principles we are using with our new engine rebuilds just concertrate on getting the torque curves nice and flat to give pull from down low. We are rasing the compression ratio on the G60 and G40 lumps so it is not necessary to run silly small pulley sizes to produce enough boost to provide good torque. The engine is doing all the work instead of the charger, a 8:1 compression ratio engine will need 10psi for arguments sake to produce the same effective compression as a 9:1 compression running 5psi. The charger is getting a easier life and you are maximising the boost you have got. The engine is also a lot more spritely off boost.

We rebuild a G40 engine, no other mods apart from raising the compression, stock pulley size running 9psi. A standerd car with 8;1 runs 113bhp and 111ft/lb torque at 3400rpm. The new engine with the only mods being. 69cc capacity increase and compression from 8:1 to 9:1.. LOL The graph speaks for itself.

140bhp/140ft/lb at 2500rpm

 

That polo outruns our Mini cooper 'S' by miles, admitidly the Mini is heavier, but has been rolling roaded at 190bhp with 160/ftlb torque, but peak torque is way high in the power band.... at the moment.. the mini is shite.. no torque = no smiles.

[Ess Three 0]

That's cracking torque from a G40!

That'll be really nice to drive...always having an instant response.

 

I guess torque is where the 1.8Ts have an obvious advantage, with the little low lag turbos and the ability ro make crazy torque, they score on the low down torque front.

 

 

332 lb-ft @ 4000RPM...nice!

[Andy92 0]

Want to know why i am loving this thread ? its different and no one has mentioned the good old 'K&N filter' :lol:

 

PS as i being daft or does that peak at 120 not 140 ?

Also what are the other two graphs ? other cars/setups ? or figures BHP/temp etc etc

[andycowuk 0]

PS as i being daft or does that peak at 120 not 140 ?

 

the torque axis will be at the right of the page. the green will be bhp at the flywheel, the red will be bhp at the wheels

[PhatVR6 0]

fit a smaller bore exhaust pipe.

[RACK 0]

I take it, that the X-Flow head on a G60 would improve torque a fair bit then due the way the air flows through it?

[dr_mat 0]

What's the difference with an X-flow head then?

[Henny 0]

In a straight through (or Cross Flow) head the air goes in the front of the head, through the cylinders, gets burnt, and the exhaust gas then goes out the back of the head... 8)

 

In a standard non-xflow 8V head, the inlet is above the exhaust so the gasses have to do a 180 degree turn during that cycle which slows the gas flow down and causes resistance thus sapping power... You also get the problem that the hot exhaust is directly under the inlet and will heat up the charge as it goes into the engine thus making it less dense and sapping some more power... :?

[dr_mat 0]

Ok. I wonder why VW didn't do it that way in the first place then? They must have had a reason..

[Henny 0]

SPACE... ;)

 

The 8V head has been around since 1980 (ish) and the cars that it was designed for didn't really have the space for the cross flow manifolds... :?

[dr_mat 0]

Gotcha.

Ta! :)

[Dubcharged 0]

Just read that document... Very enlightening.... 8)

 

There's some really good comparisons and mental imagary used, I'd recommend that people read it...

 

Thanks for posting that... 8)

 

Hey Henny, maybe you could make that link a sticky in the tuning thread since its all about understanding performance. Its a great way for people to understand the frequent (uninformed) agruments of power vs torque.

 

8)

[Andy92 0]

So that will mean to go for the Xflow option its a new cylinder head ?

 

What else will you need ? im guessing new exhaust manifold, down pipe ( if not linked to exhuast manifold ) and attachments, total cost anyone ?

 

Im guessing this would be one those mods where you dont need a dyno to confirm the extra power ?

[RACK 0]

It's not as expensive as you might think. Try and PM G-Man or beavis. That's who I'm dealing with at the min, to get mine done. But I'm getting the bottom end done too.

[LJ 0]

Hi Guys

Here's a great explanation of BHP and Torque and their implications. Good reading!!!

http://www.ls2.com/boggs/handt.htm

 

Arse! Link has died.

Anyone have a copy of the above or something similar that I can use to confuse my brain?

 

Reading up on X-Flows :) .....

[dr_mat 0]

Torque is the force you feel at your back whilst accelerating.. Power is the ability of the engine to keep pushing that hard at high speeds.. Hence the weirdo diesel thing of lots and lots of shove at low speeds but ultimately relatively slow performance in 0-60 terms.

 

So you ideally want a balance of both.. Even so I'll guarantee that tweaked Aston Martin Vantage we saw a few weeks ago, with a 7 litre twin turbo, and around 700bhp, but 1150 lbft torque will actually rotate the earth backwards under hard acceleration, or at least contribute to continental drift!! :)

[LJ 0]

Trying to find something that explains (in reasonable terms) the relationship of, number and size of valves, to power and torque. Plus how compression ratio effects all of this ... as if I didn't spend enough work time reading this excellent forum!

 

My old pinking G60 (RIP) made 199lb-ft and 185bhp at AmD and it was sweet blatting down the lanes :)

[dr_mat 0]

Trying to find something that explains (in reasonable terms) the relationship of, number and size of valves, to power and torque. Plus how compression ratio effects all of this ... as if I didn't spend enough work time reading this excellent forum!

 

Hmm. Big question. Very big question.

Back-of-envelope stuff would probably suggest that: more valves = more power, similar torque (if done right). bigger valves = more power (but possibly less torque?)

Another aspect of multi-valve is that you can get the spark plug right in the centre, which you can't do with an 2v head. This tends to improve high-rev power output on it's own.

 

Compression ratio effects I'm not too sure about. I don't know of any docs either, but I'm sure google would help there... I think the high compression ratio is what helps diesels to achieve their massive torque figures tho..?