Formula for 250hp 535i

[mholbrook]

I'm wondering what mods to get to about 240-250 hp out of an 89 535i.

Current mods I have are:

J.C. Conforti Chip
Opened up the air box for more cold air
Hartge exhaust

Planned mods are:

Fuel Pressure regulator
Mustang 19# Bosch injectors
New spark plug wires, cap and rotor

Not horsepower related mods:

17" style 32 wheels 8's 235/45/17 and 9's 255/40/17
Sachs suspension kit
M5 front sway bar, 20mm M5 Touring rear bar

Not installed:
Koni Adjustable front shocks
3.64 LSD differential

Any suggestions for more power or better handling appreciated.

Thanks,

Mike

[Brian C.]

Bruno's website has all sorts of goodies to learn about.

Here's his recipe for power.....

Good stuff to know!

Brian C.
'95 525ia

[MikeV]

Yank engine, replace with Supra TT driveline, add manual boost controller(s) and run at 15 psi or so..... should get you well into the deep-300 HP range.

Seriously, I think 250+ will be difficult with just bolt-on mods.... unless you bolt on a supercharger. I assume you mean 250 to the wheels?

[Brandon J]

You might wanna try Bruno's MAF, Schrick cam, extrude honed intake, headers, bored throttle body, port and polish head, port match intake and exhaust, and fuel injectors.

That should get you there.

[Craig]

[Sheqel]

You should have around the 240-250hp@fly right now. If you want it at the wheels, look at getting a diff, throttle bodies, cams, port and polish... and possible a bolt on supercharger kit

[Bruno]

Yep.. I think I should be close to 240... the supercharger will bring me to 300+

The hotter cam will come later, the bored throttle body will come this month.

[Craig]

30 additional horsepower sure sounds like a lot. Anyone ever actually dyno this stuff? Or are these numbers all estimates?

I'll have my car at the dyno pretty soon, it's all stock except for a BavAuto chip installed by the PO. I'm curious to see if the chip made any difference, and this should at least give some proof.

[Robbo]

I think the chip will give approx 15 extra usable BHP, what exactly do you mean by "opened up air box"?

Do you mean you have a cold air intake from outside the engine bay to the intake?

Be careful that you aren't just letting engine bay ambient (hotter) temp air into the intake.

The exhaust is probably only giving you a different exhaust note - not extra power.

To get an increase from standard 209bhp (crank) to 250bhp you need to increase output by 19.62%, this can easily be done by saving your money from exhaust, chip and air mods and using it towards a supercharger kit - 1/2 a bar boost (fairly mild) will give you about 40 - 45% increase in output (300bhp) without compromising engine reliability (too much!)

[Bruno]

30 more HP is easy to get on the 535i.

I will dyno my car in a couple of month.