M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => General Topics => Topic started by: no1_jazz on November 17, 2007, 09:54:14 AM
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Hi guys I was wondering if you could help me...
Rite what is worth doing? And which has a better outcome as overall performance, off the line and top end?
Putting a turbo into a 31.8IS M42 or simply super chipping it?
Which would give you more power and excellent bottom and top end speed.
All help much appreciated in advance.
Cheers Jazz
;)
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well a chip will net you 5-8hp depending on the kind of chip you get. a turbo will get you 70-_00 hp. one costs 60-350$, the other costs 1,000-10,000+ depending on how crazy you want to go.
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if your car is a daily driver, consider the supercharger option
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You can only reasonably get 10-15hp over stock in an m42 for a few hundred bucks.
To get more costs a lot of money. Just how it is.
That is not to say you cannot make good power but the problem is that BMW put some limitations on the engine that really cause headaches while trying to get lots of power. The 2 biggest problems are the head and the cam profile. The head is quite restrictive and the cam is not helping. Another is the fuel system, it is really not built for more than about 200hp, some will even say 180hp is hard on it.
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Cheers Guys, My car is an everyday car but as I’m studying at the same time i hardly get to enjoy it!!!
I was considering the turbo conversion but allot say that the BMW engines do not like allot of heat and already they do not have a good cooling system and by installing a turbo in, it will heat allot of things up which then will cause more problems to other engine components. So now guys I’m not to sure what to do I know one thing is that I am getting a 3.91 LSD installed.
What am looking for is a very good well almost the best bottom end i can get with this car as well as the top end speed. So any more advice on how to achive my goal with this very ole M42 engine
Cheers Guys
Jazz
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Why 3.91?
It will do little for the top end speed (and will hurt the bottom end), the car is just plain out of power. Gearing cannot really help there. It will lower your rpm during cruising though.
Cooling system, easy fix, bigger radiator.
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Why 3.91?
It will do little for the top end speed (and will hurt the bottom end), the car is just plain out of power. Gearing cannot really help there. It will lower your rpm during cruising though.
Cooling system, easy fix, bigger radiator.
Dammn that’s not good news, everyone I have spoke to told me that an 3.91LSD will improve bottom end performance as well as top end performance. I personally would not know too much about it so guys don’t think I have already gone out there and brought an lsd of any sort, I am still in the investigation stage lol so guys I need to know what will benefit the m42.
Which is the best LSD for performance which gives crazy bottom end and top end performance?
and cooling systems true can do with a bigger rad? but how much more would that cost? and is it hard to install?
Cheers for the help and advice so far guys.
Jazz
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No lsd will give your car bottom end or top end performance.
an lsd with shorter gears will get your car off the line quicker and the gears will be shorter aiding acceleration but sacrificing some top speed where as longer gears will kill your down low but will allow the car to accelerate to a greater top speed assuming your engine can push it there.
stock afaik is 4.10, 3.91 is longer
without a gearing change just adding an lsd will do little for straight line speed, maybe get it off the line cleaner on a 5000rpm launch
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No lsd will give your car bottom end or top end performance.
an lsd with shorter gears will get your car off the line quicker and the gears will be shorter aiding acceleration but sacrificing some top speed where as longer gears will kill your down low but will allow the car to accelerate to a greater top speed assuming your engine can push it there.
stock afaik is 4.10, 3.91 is longer
without a gearing change just adding an lsd will do little for straight line speed, maybe get it off the line cleaner on a 5000rpm launch
Thanks for the information Ruger, so what’s the best solution to achieve the best in both bottom end and top end speeds?
In addition if I install LSD of some sort would I have to alter my gearing to compliment the LSD to its full potential? Is LSD even worth it or is the standard 4.10 Diff which I already have in their good enough?
What’s the best way to achieve maximise performance bearing in mind I am not doing the turbo conversion but am thinking about super chipping it...... so let’s take it I already have it supper chipped and I want to still improve, because I think this is what’s really going to happen. The turbo conversion costs too much.. It’s crazy just for 60 – 70 bhp more.
Cheers
Jazz
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LSD will only add traction in slippery situations. It does nothing to add power. Basically if one wheel slips, the other continues pushing forward. In a normal diff, the wheel that slips will receive all of the power and spin more, slowing the car.
It has drawbacks in a street vehicle though.
On slippery surfaces, it can cause you to spin. When one wheel spins, power is sent to the wheel with traction, with a normal or open diff, the slipping wheel will get all of the power and the other will get none of little, the car pretty much continues forward but feels like you have lost power, the LSd, will send power to the other wheel, pushing the car out of line, and in a turn can overpower that wheel causing it to lose traction as well. Now both wheels have no traction and you are in a corner, does not take a rocket scientist to figure you will spin.
While many will tell you it is great and is even better for racing, consider that the Lotus Elise came with an open diff and no limited slip option for a while because Lotus found it was faster without LSD. LSD can upset chassis dynamics.
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A turbo setup may only get you 60 or 70, but keep in mind, in these cars, that will exceed e30 M3 power to weight. You will be beating many Mustangs at that point instead of losing to them badly.
Also, a properly prepped motor (lower compression, new cam) can make those numbers shoot sky high. I have heard rumors of 400-600hp, though I have also heard rumors of higher but also that the bocks break at 600.
Of course this costs lots of money, figure over $12k all said and done.
Once you have a chip, you can cut or mod the air box, though that is arguable as a benefit.
Coil on Plug may get you 1hp, but it is a good upgrade to make as it costs less than good plug wires and lasts far longer.
Cams can get you a few HP, but they are over $1000.
Head porting could get you a few, as well as intake port and polish, again bank...
The only real true increases in performance will come from chip, lightened flywheel, close ratio transmission or removing weight from the car.
After that, a performance rebuild, turbo, or blower is necessary. Rebuilds cost $3500 to around $8 or $9k, Blowers, about $4k, turbo, sky is the limit, it can be cheap if you know what you are doing and do it yourself with junkyard parts, or you can pay thousands, depends on how much power and your time/skill level.
The other option is an engine swap, which I am working on what our best options are, since everyone recommends the S52, which will ROYALLY screw up our handling as it is a longer engine and weights TWICE as much and costs thousands to get put in. There are some potentially great swaps for us, but all are non BMW.
Also somewhere between 200-300hp, you may want to swap to a stronger diff.
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Guys sorry for the late reply, I have just been caught up with these assignments all done now so time to relax and talk more e30’s. Lol
Rite I am more likely to get the super chip at one stage? And not the turbo
Which superchips are good for the m42 engine? Any specific ones which run well with the engine?
With regards to LSD I now understand if I am going to get the 3.91 LSD of a 325i sport I will have to alter my gearing. When you say sort the gearing out I do understand that the gears have to be re adjusted to some sort but what exactly and how would it compliment the LSD and what gears do I have to alter 1,2,3,4,5 or all?
Guys all I’m after is some crazy asss pick off and some quality mid range pick up i.e. if I’m cursing at 60mph in 4th gear and when I put my foot down I want to feel the g force pull me back and the car flying past 100mph after shifting it into 5th of course.
Guys I’m sorry if I have not made myself clear enough but if I haven’t please just let me know.
All help is appreciate
Many thanks guys
Jazz
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superchip is a made up term.
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superchip is a made up term.
Actually it is a brandname.
http://www.superchips.com
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Guys sorry for the late reply, I have just been caught up with these assignments all done now so time to relax and talk more e30’s. Lol
Rite I am more likely to get the super chip at one stage? And not the turbo
Which superchips are good for the m42 engine? Any specific ones which run well with the engine?
With regards to LSD I now understand if I am going to get the 3.91 LSD of a 325i sport I will have to alter my gearing. When you say sort the gearing out I do understand that the gears have to be re adjusted to some sort but what exactly and how would it compliment the LSD and what gears do I have to alter 1,2,3,4,5 or all?
Guys all I’m after is some crazy asss pick off and some quality mid range pick up i.e. if I’m cursing at 60mph in 4th gear and when I put my foot down I want to feel the g force pull me back and the car flying past 100mph after shifting it into 5th of course.
Guys I’m sorry if I have not made myself clear enough but if I haven’t please just let me know.
All help is appreciate
Many thanks guys
Jazz
do not go to a 3.91. the way you would have to alter your gearing if you did go to a 3.91 is to change all the gears so that its the same as having a 4.10 in the rear. the rear end gearing, or any gearing is not your problem in this case. you problem is lack of power.
you will never have that feeling without going to a stroker or forced induction of some sort, whether its a turbo or a supercharger. or a motor swap, or buying a new car of course.
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doning atlanta makes a nice supercharger for our cars I hear
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they do, but not with that spelling. It's Downing Atlanta ;). Their kit is actually for the m44 and reports as to whether or not the m42 kit is even in the works are not reliable at all. All it takes is a serpentine belt conversion, but you still have to be careful about predetonation.
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they do, but not with that spelling. It's Downing Atlanta ;). Their kit is actually for the m44 and reports as to whether or not the m42 kit is even in the works are not reliable at all. All it takes is a serpentine belt conversion, but you still have to be careful about predetonation.
The m42 kit does exist, but it seems to be a work in progress.
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Thanks allot to all for the help and advice.
Guys now that I know a 3.91LSD is not worth the doing, a supercharger is the way forward if I want to KEEP the engine (m42) which I do. So shall I just keep the original diff in there and not change it to another?
After installing the supercharger what will I achieve for example would I:
- Achieve a real good bottom end
- A good 0-60mph time
- Achieve a reasonable good top end
Would I have to alter anything else so that the engine compliments the supercharger and vice verser?
Many thanks
Jazz
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?????
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Keep in mind we do not spend all day here.
How much you change for the supercharger depends on how much pwer, and how you go about it.
Downing Atlanta has done A LOT of work on this and getting 180hp is not easy. Their kit requires a chip, new brake booster, new A/C pump, new belt system, injectors, manifold and a fuel pressure regulator. It can still run lean. The fuel system on our cars is not up to the task in a blown environment.
Doing it yourself, you may want to look at how they did it, as you may be shocked at what all is involved. Grassroots Motorsports has the article, though I know at least part of it is on here someplace.
The bad side of this is that you are adding a blower to a high mileage engine. A rebuild will cost you a few grand, as does the blower. One mistake and you could easy lose the motor. You may want to look into the Metric Mechanic motor at that point. More power, fresh motor, no blower, stock appearance, stock weight. It is an m3 killer in m42 clothing.
While cost is an issue, you can easily reach the same price and wind up with a hunk of junk that does not even run. Theirs comes with a warranty and their support, which is EXCELLENT. Also that engine can add value to your car. A homegrown setup rarely if ever adds value, and a D/A blower setup will likely not really add any value, though it could add some. Performance builds by reputable places increase a cars value, rather than lowering it like a homegrown setup can do.
You are dumping a lot of money into a car that currently is not worth much, but could be in the future, you should look at it as such. If it is a hobby and you have no plans on keeping it or something, you have options, but if you plan to keep it for a while, do it right.
Another thing to keep in mind is insurance. Once this is done, your car will be worth significantly more. You may want to get better insurance, one with an agreed upon value. This way if it gets wrecked, you can get it fixed. Agreed upon value is an amount set by you and the insurance company that should the car be totaled, you get that amount, not the $2600 the book says your car is worth (even though you have $8k in the engine alone).
Not all insurance companies will do this, and it can cost more.
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LSD will only add traction in slippery situations. It does nothing to add power. Basically if one wheel slips, the other continues pushing forward. In a normal diff, the wheel that slips will receive all of the power and spin more, slowing the car.
It has drawbacks in a street vehicle though.
On slippery surfaces, it can cause you to spin. When one wheel spins, power is sent to the wheel with traction, with a normal or open diff, the slipping wheel will get all of the power and the other will get none of little, the car pretty much continues forward but feels like you have lost power, the LSd, will send power to the other wheel, pushing the car out of line, and in a turn can overpower that wheel causing it to lose traction as well. Now both wheels have no traction and you are in a corner, does not take a rocket scientist to figure you will spin.
While many will tell you it is great and is even better for racing, consider that the Lotus Elise came with an open diff and no limited slip option for a while because Lotus found it was faster without LSD. LSD can upset chassis dynamics.
Rubbish in my opinion...
Having an LSD makes a car endlessly more predictable when driving quick, be it on a track or just spirited driving on the road.
It does make the car step out abit easier in wet conditions but it doesn't mean your going to spin unless your abit of a muppet to not react to it.
When it does break loose it will b alot easier to control than if you had an open diff.
The fact that an Elise is a mid-engined car would have had a factor in it not needing an LSD, since the extra weight over the rear would give the car the balance it needs. An Elise can't really be used as a comparison in an E30 needing an LSD or not since the cars couldn't really be any more different.
In my opinion I reckon there isn't any front engined rear wheel drive car that would handle or be quicker with an open diff rather than an LSD.
Racing 2-way diffs such as that used in drifting will have a bad effect on handling on the road alright, but a standard BMW diff that only has around 25% lock in any case will only improve it.
If your after low end performance a supercharger might be your cup of tea.
200bhp is easily enough to attain with doing a good job like one of the 319iS guys on E30 zone has just finished doing to his M42.
Guys all I’m after is some crazy asss pick off and some quality mid range pick up i.e. if I’m cursing at 60mph in 4th gear and when I put my foot down I want to feel the g force pull me back and the car flying past 100mph after shifting it into 5th of course.
A chip, light-weight fly-wheel, and a few other small things should give you something decent like this since the car should pull in 5th as it did in 4th and 4th as it did in 3rd and so on when it was standard.
No need to shift into 5th though...
A chipped iS is capable of as near as makes no difference 100mph in 3rd;)
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Coil on Plug may get you 1hp, but it is a good upgrade to make as it costs less than good plug wires and lasts far longer.
thats interesting, not really for the power but more for it being cheaper and more durable than stock. i need new ignition wires/spark plugs so might as well, swap it for e46's COP ?? what does that involve? i guess i'll have to machine a plate that will accept the cop insted of the old bmw plastic cover. and what about the electronic, solid state distributor, (not sure of the actual name)
is this a simple tear and replace or do i have to build custom electronic. i can deal with anything mechanical but i would want to risk to build high voltage faulty connections
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well i got some of my answers here
http://bmw.e30tuner.com/my318is_pic_copcon.php
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Rubbish in my opinion...
Having an LSD makes a car endlessly more predictable when driving quick, be it on a track or just spirited driving on the road.
It does make the car step out abit easier in wet conditions but it doesn't mean your going to spin unless your abit of a muppet to not react to it.
When it does break loose it will b alot easier to control than if you had an open diff.
The fact that an Elise is a mid-engined car would have had a factor in it not needing an LSD, since the extra weight over the rear would give the car the balance it needs. An Elise can't really be used as a comparison in an E30 needing an LSD or not since the cars couldn't really be any more different.
In my opinion I reckon there isn't any front engined rear wheel drive car that would handle or be quicker with an open diff rather than an LSD.
Racing 2-way diffs such as that used in drifting will have a bad effect on handling on the road alright, but a standard BMW diff that only has around 25% lock in any case will only improve it.
Ever heard of drag or friction?
An open diff has near zero drag while cornering.
A limited slip creates some because it is trying to keep the wheels together. This not only can slow lap time but also cause the car to be a bit more easy to spin. Drift guys use a whole list of diffs including ghetto oval track and drag modded diffs... Welded. For the above reason.
As long as the tires do not break loose in corners, the open diff will be the faster diff. Do they always stay glued in place no, but most of the time they do.
The problem is that in high power cars they can spin the tires regardless, and an open diff would just mean one wheel would break loose that much faster. In a momentum car, an open diff is not a problem, you are not nearly as likely to overspin the tires. The higher power can now get on it harder out of the corner, however, cornering ability does suffer some as LSD has been known to create push for the above mentioned reasons, it is trying to spin both wheels at the same speed, which is not desirable in a corner. The tires will then fight each other.
How much is lost is what determines if it is better or not for each track.
Oh, one other thing, an LSD is harder on tires and obviously gas.
The diff should be looked at as a tuning option like spring and shock rates. Not as an all around performance enhancement such as a chip or headers. This is why there is different types of diffs as well as adjustable diffs.