Hello From Norway!

N

nilsp

Member
First found this forum when looking for exhaust header and scavenging information, and found lots of good and well explained information, so looking in now and then, been away a while, but better introduce myself a little.

My car and engine isnt the most common in here I guess, a old bmw m3, the first generation that was a homologation special for racing in 86 and forward.

Original they had a detuned 2.3 liter inline with 200bhp. Racing versions was 300-380 bhp (latest 2.5 liter in 92)

My car is a road and trackday car and Im not aiming that high, but I have gotten somewhat been carried away with this and found NA tuning very interesting.
Ended up stroking it to 2.66 liter and lots of nice parts making it work.

So a couple of $K grands later I have a very (in these terms) strong little engine, making 330nm and 325 hp on regular 95 fuel and made to be very driveable with top hp at 7600rpm.

But still struggling with a big torque dip, and needed to get ideas on this again.


So I`ll be back for more ideas on this.
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glad too see you post!
welcome to the forum
and yes that is darn impressive and a nice looking car,
most of us would be very pleased to own.
just curious?
have you ever considered adding a turbo?
 
nilsp said:
First found this forum when looking for exhaust header and scavenging information, and found lots of good and well explained information, so looking in now and then, been away a while, but better introduce myself a little.

My car and engine isnt the most common in here I guess, a old bmw m3, the first generation that was a homologation special for racing in 86 and forward.

Original they had a detuned 2.3 liter inline with 200bhp. Racing versions was 300-380 bhp (latest 2.5 liter in 92)

My car is a road and trackday car and Im not aiming that high, but I have gotten somewhat been carried away with this and found NA tuning very interesting.
Ended up stroking it to 2.66 liter and lots of nice parts making it work.

So a couple of $K grands later I have a very (in these terms) strong little engine, making 330nm and 325 hp on regular 95 fuel and made to be very driveable with top hp at 7600rpm.

But still struggling with a big torque dip, and needed to get ideas on this again.


So I`ll be back for more ideas on this.
index.php

index.php
Click to expand...

Welcome.
A friend used to into those BMW M3s.

Changing rear diff gears to a Lower gear 1-2 steps will help.
Numerical higher.

If you can get 4.30 -4.88 gears.

If not made a 3rd member swap to an early Dino Ferrari unit.
They had those low gears.

Other possible option is the rear diff from a 1st gen Honda CRV
Auto trans had 4.30 gears.
 
Dino Ferrari 3rd members were on ebay a few years back in Los Angelous California a guy was selling.
May be gone now.
 
The strongest most ready available IRS Diff is from a Dodge Viper.
They won't be real low gears stock since the V10 had lots of torque 480-600 ft/lbs depending upon year.
But they are Super Dana 44s.
Gears made from 3.07 to 5.38 for them.

Have to race car fab to mount it and use it.
 
Grumpy said:
glad too see you post!
welcome to the forum
and yes that is darn impressive and a nice looking car,
most of us would be very pleased to own.
just curious?
have you ever considered adding a turbo?
Click to expand...

Thanks!

Turbo? Naaah.. I did plan that many years ago, but I fell back to these cars were made for racing with an angry little 4 pot, so went into this NA tuning world which of course isnt the easy or cheap way to go,but these cars need to be like that in my opinion :)


Maniacmechanic1 said:
Welcome.
A friend used to into those BMW M3s.

Changing rear diff gears to a Lower gear 1-2 steps will help.
Numerical higher.

If you can get 4.30 -4.88 gears.

If not made a 3rd member swap to an early Dino Ferrari unit.
They had those low gears.

Other possible option is the rear diff from a 1st gen Honda CRV
Auto trans had 4.30 gears.
Click to expand...

Thanks!

Well, yes.. changing the rear diff was a easy way to go for a little more power (or think so) back in the days.
But since I want to have it driveable for longer journeys, I cant have a hearing like that.

And this engine is in another league compared to the stock ones which can feel quite lazy, but are quite fast when driven hard.
Im also using the european dogleg gearbox which they didnt have in the U.S, and therefore also a differnent diff ratio!
 
Couple of other photos.
One at the famous nordschleife in Germany.
Last one when engine in dyno a couple of weeks ago.. testing some stuff with x pipe and intake runner length..
 

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nilsp said:
Couple of other photos.
One at the famous nordschleife in Germany.
Last one when engine in dyno a couple of weeks ago.. testing some stuff with x pipe and intake runner length..
Click to expand...
Nice.
It's built for high rpm use I can see.

What can possibly be done is use adjustable custom camshaft sprockets to advance or retard the cams.
Advance a bit 2-4 degrees and see if some low end torque recovers.
Track use move the Cam timing back where it is now.
 
I am more familiar with the later Mitsubishi EVO engines from the race shop I worked at in past.
Typical upgrade was adjustable upper cam sprockets belt drive.
 
Supposed to use a camshaft degree wheel but the shop had a chassis Dyno and camshaft timing changed right on Dyno then retested.
 
Maybe I will start a new post with my dyno results and stuff.
Yes, I consider adjusting the cam timing a little more, they are both adjustable, but didnt have the time when in the dyno unfortunately.
But did test some various stuff with x-pipe position and on intake runner length.
(Swapped the 4-1 header with a 4-2 long primary)


Here is a shot of a test with the 4-1 before swapping header.
Can see my big torque
 

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nilsp said:
Maybe I will start a new post with my dyno results and stuff.
Yes, I consider adjusting the cam timing a little more, they are both adjustable, but didnt have the time when in the dyno unfortunately.
But did test some various stuff with x-pipe position and on intake runner length.
(Swapped the 4-1 header with a 4-2 long primary)


Here is a shot of a test with the 4-1 before swapping header.
Can see my big torque
Click to expand...
Torque is not that bad.
Typical 400 ft/lbs wanted at least down low in most cars at the flywheel.

It's the Large Intake Plenum volume.
Air speeds slowing down at low Rpms.

Prefer Lower or Deep 4.10, 4.30, 4.56, 4.88 In such cases.

Other option is too lighten the car.
Reduce driveline mass.
Magnesium Road Race wheels that weight 10-15 lbs each.
expensive.

Vintage Gasser Era drag racers all used Magnesium wheels. Highly prized today $$$$$.
 
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