[mblaucoupe135]

I have a 335is, which I love. However, I was curious about one thing that I was hoping someone could shed some light on for me. The car has the same n54 engine as the 1M and z4 35is, but both those cars have 335hp and mine only has 320hp. So I'm curious as to why the difference in hp?

[CallMeAl]

Not sure why they do this but it would be related to the ECU. If you get a dinan Cobb or another ECU chip you can get a lot of HP out of it.

[ErvGotti]

More than likely a marketing thing for BMW. Same motors they're more than likely running a more aggressive timing curve or slightly more boost. Get a tune and call it a day.

[BEAR-AvHistory]

DUH Originally posted this to the wrong thread:

My 335is dynoed at 319whp on a DynoJet with 93 octane against the 320BHP that BMW advertises it at. Saw the 1M dyno at 331whp against the 335BHP that BMW uses. So the 1M is stronger & in proportion to the advertised spread. It would be a bit more of a tune in the ECU because just about everything else is the same.

Main thing is both numbers are bogus because using the BHP scale they both are underrated quite a bit.

[BMV///M3]

A bit more aggressive tune in those cars. Like others said, you could make that 335IS very fast with Cobb or JB4. Opening a can of worms tuning though.

[username604]

Maybe the cars are dynoing like 60bhp above their bhp spec because of the boost function?
(I'm a newb with the whole boost function)

[fun2drive]

BMW always specs their engines as - 0% to + 5% HP. Many times these engines run well above that.
In the case of the 1M etc it is purely a more aggressive tune.
Well under the potential of this engine...

[NvTwist]

The 15HP difference between iS & Z4 is due to the increased under hood clearance in the Z4, it allows for a larger & easier breathing intake. The Engine, ECU & OverBoost are the same in both. Of course a slight diff in software to take advantage of that increased air flow thats avail.

[mblaucoupe135]

Thanks for all the responses so far. I know i could do an aftermarket tune to get more power, it just seems like the least bmw could have done is make it the same as the 1m and z4 35is. I could understand the 1m having more cause it's an m car, but not the z.

I'm thinking i should write a letter to bmw asking for my 15hp! Lol

[Canada Jeff]

I love my JB4, I can turn it on or off thought the steering wheel. it's like an "M" button for non M cars :-) ! Huge difference. turns on or off in less than 5 seconds.

[Nonecure]

Why would you ever want to turn off a tune? If you turn the tune off and on, wont that make the ECU have to keep relearning?

I personally have Cobb and love it. I have heard good things from JB4 as well. I just don't see the point in turning it on and off.

[mblaucoupe135]

My car is leased which is why I am concerned about getting a tune and haven't done it yet.

[BEAR-AvHistory]

One reason to shut it down is a road trip. I am running 96 octane as a DD with a custom 335is Map6 (set boost etc. by RPM). If I take a trip & gas quality goes down I can hit the steering wheel & go back to Map 0 stock or Map5 (autolearn). Map 0 is also good for a quick switch for a dealer visit or state emissions testing.

If its a long trip & I want to go into cheapo mode Map 8 will cut out the turbos for an MPG Map. No relearn going back to Map 6. Map 5 would take at least 3-4 WOT pulls in 3rd gear to get its memory back. Map 5 is also the Map to use with an E85 mix up to about 50% although 35% is recommended for my car.

Is the on the fly selection necessary NO - Is it nice to have YES

Both systems are very good for a daily driver & its hard to go wrong with either one. My choice was based on overall features available & customer service both of which lived up to my expectations.

The things I use the most are the system ready lights, Gauge 50% throttle hijack for Water Temp & Boost Pressure + the shift lights which I set at 6250rpm.

[Nonecure]

OK, that makes perfect sense. I just run a 93 octane map and don't worry about it, and I don't use my car for long distance traveling. For higher boost maps and traveling, your setup sounds really good.

[Nonecure]

Originally Posted by mblaucoupe135

My car is leased which is why I am concerned about getting a tune and haven't done it yet.

The Cobb will let you easily remove the map when you take your car in to be serviced. Also if you turn your car in after the lease, you can pull the Cobb map off and use it on another car, or sell it. The chip method works too, but you have to physically remove it each time you take your car in.

[John 070]

Originally Posted by BEAR-AvHistory

One reason to shut it down is a road trip. I am running 96 octane as a DD with a custom 335is Map6 (set boost etc. by RPM). If I take a trip & gas quality goes down I can hit the steering wheel & go back to Map 0 stock or Map5 (autolearn). Map 0 is also good for a quick switch for a dealer visit or state emissions testing.

If its a long trip & I want to go into cheapo mode Map 8 will cut out the turbos for an MPG Map. No relearn going back to Map 6. Map 5 would take at least 3-4 WOT pulls in 3rd gear to get its memory back. Map 5 is also the Map to use with an E85 mix up to about 50% although 35% is recommended for my car.

Is the on the fly selection necessary NO - Is it nice to have YES

Both systems are very good for a daily driver & its hard to go wrong with either one. My choice was based on overall features available & customer service both of which lived up to my expectations.

The things I use the most are the system ready lights, Gauge 50% throttle hijack for Water Temp & Boost Pressure + the shift lights which I set at 6250rpm.

Totally cool stuff......sometimes I wonder if stations are really pumping 93 when you pay for it....one day there will be random octane testing.....

[shanecarmaster1]

Originally Posted by BEAR-AvHistory

If its a long trip & I want to go into cheapo mode Map 8 will cut out the turbos for an MPG Map.

Hmm never heard of an N54/55 doing that. Does that mean it accelerates and feels like a 330i or something? How does it feel?

[mblaucoupe135]

Originally Posted by Nonecure

The Cobb will let you easily remove the map when you take your car in to be serviced. Also if you turn your car in after the lease, you can pull the Cobb map off and use it on another car, or sell it. The chip method works too, but you have to physically remove it each time you take your car in.

That sounds cool, but has it been confirmed that there is no way the dealer can tell you had aftermarket software on the car?

[Canada Jeff]

Originally Posted by Nonecure

Why would you ever want to turn off a tune? If you turn the tune off and on, wont that make the ECU have to keep relearning?

I personally have Cobb and love it. I have heard good things from JB4 as well. I just don't see the point in turning it on and off.

I actualy forgot about the learning part of the chip. I have been turning it off because I didn't want to put any more stress on the turbos when I didn't need it. But, I just signed an after market warranty contract yesterday so I may aswell leave it on all the time. except when something fails and it needs service

[Envuks]

It was never yours to begin with.... Get a tune!

[SaMaster14]

Originally Posted by mblaucoupe135

I have a 335is, which I love. However, I was curious about one thing that I was hoping someone could shed some light on for me. The car has the same n54 engine as the 1M and z4 35is, but both those cars have 335hp and mine only has 320hp. So I'm curious as to why the difference in hp?

The pre 2010 335i also has the N54, but it only puts out 300hp and 300lb/ft. It's all about tuning. The N54 is capable of putting out around 380-400hp just by messing with the plugs. BMW can't have their high end base models outperforming their M cars now can they?

[NoTempoLimitN54]

Originally Posted by NvTwist

The 15HP difference between iS & Z4 is due to the increased under hood clearance in the Z4, it allows for a larger & easier breathing intake. The Engine, ECU & OverBoost are the same in both. Of course a slight diff in software to take advantage of that increased air flow thats avail.

I've read that the N54 "S" in the 1M has special downpipes with freer flowing cats. Apparently, these can be retrofitted onto other N54 cars.

I think there may be a temperature issue with the Z435is as well. The large underhood cavity giving better cooling.

I'd be suprised if there are any major differences in the software between the 335is, Z435is and 1M (and possibly the N54 PPK software). Remember the engine+software has to get certified for emissions which is very costly, especially in the U.S.

I'm sure BMW would want to get maximum return on investment by using the software in three different models with the same engine.

Anybody got any knowledge to the contrary?