LSD & Lightened flywheel

[mwalley1]

I've ordered a new engine & going to refurb gear box but have been thinking that whilst its all apart it maybe worth thinking of a Limited Slip diff (LSD) & lightened flywheel!

Has anyone tried or got them & what do you think of them???

I have driven a track car with a LSD before and after it was fitted and it made a amazing difference but this was on a front wheel drive car!

Thanks a lot Matt

[Deleted]

I was wondering this myself, between LSD diff, and quaife ATB style? Would it promote understeer followed by massive oversteer on lift off. Bearing in mind that most diffs would be set up for 1500kg focus rs etc.

I reckon the quaife ATB may have advantages, but being able to adjust the pressure in a plate type has other benefits.

[andychalmers]

My oppinion of diffs are that they are great in race/rally enviroments but no big advantage on the road. Plated diffs are over the top on a road car due to their price, harsh nature (when driving) and need servicing etc. Quaife ATB diffs are a good compromise, not as good as a plated diff however work well and they dont need servicing plus are pre set. They drive like a std diff with increased grip. I've never driven a Rocket yet (soon tho) and I'm sticking with a std diff. I used to rally a 205 with a std diff and it seemed to handle so much better than my other cars with atb or plated diffs, but was pants when I went off the track lol. But then again Rockets are quite high power for such a low weight & in the wet the ATB could be very good if your a aggressive driver.
I wonder if a FWD focus ATB diff will be as good as it could be sat in the back as they are set up for turning etc being designed for a FWD car setup, hmmmm. Will still increase grip tho and help in corners.

I think it all boils down to how much of a aggressive driver are you? If you love to red line, drift, slide & take your car to the track then yes get one. If your a occational put your foot down casual driver then prob not worth the extra money.

I wonder how many people would actually relise the difference between a std diff & a Quaife ATB diff?

[mwalley1]

Agree on price of diff and whether it's worth it! Have driven a car before & after Having a wavetec diff put in it and it was a massive difference on the amount of grip you get especially coming out of corners! But this was on track! Think I'll stick with the standard diff to start with then maybe look at upgrading next year! Have decided to go for the lightened flywheel tho!

[motorhead]

I don't know about anyone else, but even with 191bhp we've not had any problems with wheelspin, except in the wet, and frankly, for obvious reasons, rockets are just no fun in the wet...
Perhaps you should drive one hard first and see for yourself, or if you're ever at a trackday and see us, you're welcome to a passenger ride.

As for lightened flywheels, on any car, they make a massive difference in the first 2 gears, if I had the choice I would always go for one.

[airforceone]

Interesting topic.

Not looking for a LSD at the minute but the benefits of a Light weight flywheel are interesting.
I have seen a few aluminium ones for around £250 that are about a third of the weight of a normal flywheel.

I don't intend to use the car for track use initially but am just at the stage of putting my engine and gearbox together. I have a new clutch kit so was looking into flywheel options just before this thread started.

Would it make any difference to normal road use, mainly thinking of splitting the engine and gearbox to replace it in the future, if it's worth doing better to do it now.

Ned

[ollieballs]

lightweight flywheels spell nothing but trouble to me.. great for a track only car but bloody annoying for normal use.
scenario:
if you sit in traffic the idle turns over too low and your engine splutters and dies...
you restart the engine and lift the clutch to take off and without giving it a huge amount of revs it stalls again..(and if you do give it grunt it flies into the car infront of you) this is particularly annoying when trying to reverse into a parking bay... makes it almost impossible. meaning you end up constantly rideing the clutch and getting through many more of them.
so you tune the idle slightly higher to compensate and keep your engine running and end up with heat problems and crap fuel efficiency... and for what? a very slightly faster take off speed.
we've got a dax with all that jazz and its nothing but trouble haha... rant over

[ollieballs]

i mean... some race cars dont even have flywheels... thats why youl hear a formula one car revving like crazy in the pits and then when they turn it off it stops dead instantly without any momentum revs. but they are impossible to drive slowly... most people will stall a race car a million times before they get a proper take off for that reason

[motorhead]

Depends on how far you go. I have another car with a Rover V8 in it, and people sell lightened flywheels for them, and they're only a few pounds lighter (around 20%), so a lot of those problems don't really apply, although not sure why fuel economy is much of a problem in a MEV, it's not like you go to work or shopping in it, or do you??

[ollieballs]

well with an engine as reliable as the focus's are theres no reason why you cant in summer! i just see it as takeing an engine that will run fine and drive comfortably and turning it into something unreliable that will break down more often... thats fine if youre bombing it round a track and want to rebuild the engine every week but as a road car its just impractical in my opinion! reversing is the worst part id say.. eventualy youre gonna want to park it in a bay whether that be at a car show or tescos!

[ollieballs]

i cant pick fault in an lsd though.. although they are a tad pricey for the small gain in performance

[Tim Kerr]

I run a Quaife LSD and have a lightened flywheel. Its true my car is more track day orientated but I also drive it on the road and have made the trip over from Belfast to stoneleigh.

The car doesn't drive much different on the road but on track the diff is great. It lets you get the power down earlier and if the back steps a bit you can still keep the power down.

I am not one for drifting but it does let you get the back out and easily get it back. But for pure laptime it does make a difference.

Tim

[mabbs]

From my opinion, a car is better with an LSD, but it comes into play when you are pushing the car. If you want a bit of light back lane fun then their may be justification to not invest , but when your on the track, you will get faster and faster throughout the day and this is when the LSD helps. The Quaife ATB LSD does a very good job as is - plug and play. The plated diffs are cheaper and adjustable and may require a bit of future maintenance. The engine/gearbox is easy to get out of the Rocket so it may be worth while to use it as a future mod.

Lightened flywheel - in my experience, if you want a easy weight saving that helps the acceleration of the car then a good idea. It will make the car not so nice to drive from the bite of the clutch if you are stuck on the M25 and maybe a bit more snappy. If you are going to drive your car to work through heavy traffic quite often then may be not a good idea, but if your are going to be traveling through the gears at a good pace then it may be worth while. Again not a major winter mod.

My 2 p worth if it helps