[IISevv]

Hey guys, just writing this article for fun, trying to help out some 328i owners who are wanting to modify their vehicle. Hope you enjoy and find it helpful.

Most people think modifying an N52 is a pointless endeavor but that simply isn't true. 328's and e90 325's can be found used for $3,000-$4,000 less than a 335 with similar mileage (KBB values and local market price), but can make almost the same power as a stock 335 for arohnd $2000. Obviously if you want big power you'll need a 335, but this is for those guys who just want to be close to a stock one.

One of the best, If not THE single best modification for an N52 is the 3-stage intake manifold from the 330i. It uses sensors to direct air to the cylinders that need it most; the parts cost about $300, and with a tune has shown dyno numbers of 260 horsepower. Another easy modification is a secondary cat delete. It has no 02 sensors so will not cause any issues and any local muffler shop should be able to do it for around $50-$75. With a tune this mod will produce about another 10 horsepower. The perfect last mod to go along with the upgraded intake manifold is a set of headers with either no or high-flow cars, and a higher-flowing intake. You can make one yourself using piping and a brand-name cone filter. It wont sound quite as good as a performance CAI, but Will do the job and doesn't cost $400 either. With the intake, a set of headers should produce around 25 horsepower if tuned properly.

It would be recommended to do all of these mods, and then tune just to save on cost. All together, dyno figures have shown that they should produce around 290 horsepower at the crank. Not quite 335i competitive, but will make they 328i damn fun on a budget. Here is a breakdown of what each mod will net you.

Intake manifold: 20 by itself/30 if tuned
Tune by itself: About 10 horsepower
Intake by itself: Aboout 10 horsepower
Headers by itself: about 15 horsepower, slightly more with the right intake
Secondary cat delete: About 10 horsepower

IMPORTANT DISCLAIMER:
This article is entirely based on my opinions and what I have seen in terms of dyno numbers. I cannot guarantee any specific gains, I'm simply trying to help out my fellow 328i people who maybe can't afford a 335. If you have any questions I'll be happy to answer them to the best of my ability. I take no responsibility for any damage you cause to your car by modifying it, and removing cats is illegal in some states.

[Welcome to NBA Jam]

An intake is not going to make 10 more horsepower on a NA engine, that I can tell you for sure.

[IISevv]

Originally Posted by Welcome to NBA Jam

An intake is not going to make 10 more horsepower on a NA engine, that I can tell you for sure.

Huh...really. So that's why my car dynoed 10 horsepower more after an AFE intake. I'm not pulling these numbers out of my a** I've seen dyno sheets for all of these modifications individually.

[racermp]

Trade for 335... honestly, not worth pushing that more that much especially when there is one from factory

[IISevv]

Originally Posted by racermp

Trade for 335... honestly, not worth pushing that more that much especially when there is one from factory

I understand 335's are a better deal but that wasn't my point. 335's are more expensive to buy, maintain, and insure and not every high school or college student can afford that. My article was specifically for people who can't get a 335 for whatever reason.

[Faredo]

Originally Posted by racermp

Trade for 335... honestly, not worth pushing that more that much especially when there is one from factory

Ya i dont know, I think the OP has a point. If a high school kid buys a 335i good luck keeping it stock. they will mod it and and probably be in over their head.

At least with an NA you have a safer and less expensive ceiling to cut your teeth on.

[racermp]

Originally Posted by IISevv

I understand 335's are a better deal but that wasn't my point. 335's are more expensive to buy, maintain, and insure and not every high school or college student can afford that. My article was specifically for people who can't get a 335 for whatever reason.

I read again and I understand what you are trying to do. here's my take tho, modding a car usually makes it less reliable, give it worse mpg however benefit is power. sometimes. a good used 328i would be around 6k or so. similar 335i would.be around 8k. say like 07. 335i has it's fair share of issues, but factory car with 300hp is better than modded car with 300hp. just all the testing and development that goes.into a factory car.

[racermp]

Originally Posted by Faredo

Ya i dont know, I think the OP has a point. If a high school kid buys a 335i good luck keeping it stock. they will mod it and and probably be in over their head.

At least with an NA you have a safer and less expensive ceiling to cut your teeth on.

that is true. in that terms if u r doing just a.bit of.modding, 328i is better

[IISevv]

Originally Posted by racermp

I read again and I understand what you are trying to do. here's my take tho, modding a car usually makes it less reliable, give it worse mpg however benefit is power. sometimes. a good used 328i would be around 6k or so. similar 335i would.be around 8k. say like 07. 335i has it's fair share of issues, but factory car with 300hp is better than modded car with 300hp. just all the testing and development that goes.into a factory car.

Maybe where you live that's true...here in Phoenix a 328 is around 6 grand but a clean 335 with around 100k miles is around 10 grand or more. People here try to sell 150k mile beat up 335's for 8 grand...good luck keeping that reliable. I was just basing it off of the market prices here. The used car market in Phoenix is pretty ridiculous

[racermp]

Originally Posted by IISevv

Maybe where you live that's true...here in Phoenix a 328 is around 6 grand but a clean 335 with around 100k miles is around 10 grand or more. People here try to sell 150k mile beat up 335's for 8 grand...good luck keeping that reliable. I was just basing it off of the market prices here. The used car market in Phoenix is pretty ridiculous

haha yea true these cars are getting old, hard to find a good clean one. the ones that are selling clean ones are too high

[IISevv]

Originally Posted by racermp

haha yea true these cars are getting old, hard to find a good clean one. the ones that are selling clean ones are too high

But e90 m3's are getting crazy cheap, going into the mid 20's with around 60k miles

[rick100]

unless you are going SC with custom tune and headers there is not way you are getting 300 whp in a 328

Even 300 at the crank is unrealistic , unless you are one of those people that thin there is 25 % loss .

I ve seen many dyno charts in the na section with full bolts on 328s ( meaning exhaust, headers, 3 stage intake , bpc or aa tune) and most of them are getting between 220 - 240 whp ( higher number on manual transmission) . I believe one guy claimed 250 whp with a more custom tune .

I ll only agree on one thing , a full bolts on 328 will cost you around 2000 $ in the lower end , and it will net you about 30-40 whp on a good day . The driving experience on a full bolts on 328 is worth that money , sure it is not crazy fast , but the car is not dull anymore , perfect for the street .

[racermp]

Originally Posted by IISevv

But e90 m3's are getting crazy cheap, going into the mid 20's with around 60k miles

haha yes that too. when I bought my 335 last year, I was debating between a m3 and 335i. m3 was 09, 70k for 25k. but torque and mods got my hooked on the 335

[IISevv]

Originally Posted by rick100

unless you are going SC with custom tune and headers there is not way you are getting 300 whp in a 328

Even 300 at the crank is unrealistic , unless you are one of those people that thin there is 25 % loss .

I ve seen many dyno charts in the na section with full bolts on 328s ( meaning exhaust, headers, 3 stage intake , bpc or aa tune) and most of them are getting between 220 - 240 whp ( higher number on manual transmission) . I believe one guy claimed 250 whp with a more custom tune .

I ll only agree on one thing , a full bolts on 328 will cost you around 2000 $ in the lower end , and it will net you about 30-40 whp on a good day . The driving experience on a full bolts on 328 is worth that money , sure it is not crazy fast , but the car is not dull anymore , perfect for the street .

I meant 300 crank horsepower, not at the wheels. They make about 230 stock. Add up all the mods and that's close to 300 crank. Sure not every car will make that but you can make more power than you think. My e36 325is is around 260 horsepower and beats m3's, all it has is a set of m3 cams and a tune. Meanwhile m3 people are making only 50 horsepower more than me and they spent 5 grand on a supercharger. I can't really explain it but the dynos don't lie

[IISevv]

The old and new...someone ran a redlight and totaled the e36 so it's becoming a future turbo project

[NiNeTyOne]

Just changing the intake does NOTHING. In fact, the performance goes down. You need the tune to activate the DISA valves.

How do I know? I've done all this except the EM. 300? You're on crack.

[IISevv]

Originally Posted by NiNeTyOne

Just changing the intake does NOTHING. In fact, the performance goes down. You need the tune to activate the DISA valves.

How do I know? I've done all this except the EM. 300? You're on crack.

Ok you might be right about the tune. I was only basing this off of my own experience combined with what I've heard from others. I thought it might be helpful to have it all in one place. But I don't think close to 300 is unrealistic at all. There are multiple members who have posted Dyno figures for the intake and other mods separately, and combined should be close to 300. Headers plus the intake manifold and a tune should result in an increase of 40-50 horsepower or a total of 270-280 at the crank, so 300 crank with the other mods isn't unrealistic at all

[WhiteBeard]

Yeah OP, I appreciate your enthusiasm, but please check your numbers as this gives newbies false hope. To gain 70hp on a 328i you need more than 3SI and a tune. Many members here have 3SI, a tune and headers and still they are not anywhere close to 300hp. Besides you'll run into troubles quickly with this kind of mods - exactly what you are bashing on 335s huh

This was all done and redone and talked to death million times. Don't forget about n51 guys who already have 3SI and still realistically make only 180hp on dyno

[IISevv]

Originally Posted by WhiteBeard

Yeah OP, I appreciate your enthusiasm, but please check your numbers as this gives newbies false hope. To gain 70hp on a 328i you need more than 3SI and a tune. Many members here have 3SI, a tune and headers and still they are not anywhere close to 300hp. Besides you'll run into troubles quickly with this kind of mods - exactly what you are bashing on 335s huh

This was all done and redone and talked to death million times. Don't forget about n51 guys who already have 3SI and still realistically make only 180hp on dyno

I'm sure both of us can agree that a 3 stage intake will result in about 20 horsepower with a tune, right? There are dyno sheets all over this forum proving that. And we can also probably agree that catless headers when tuned will net you About another 20-30 horsepower. Again there are dyno sheets everywhere proving that. And with a secondary cat delete, multiple members have proven it will net you 5-10 horsepower. Just with those things you're at around 280 horsepower if not more. It might not be exactly 300 but for the purpose of my article it's close enough

[IISevv]

I don't know about copyright violations but on this forum a few members Have posted official active autowerk dyno sheets. They show gains of about 22 for the 3si and gains of 30 for catless headers paired with tune and charcoal delete. You guys are the ones on crack, do your homework

[NiNeTyOne]

Originally Posted by IISevv

I'm sure both of us can agree that a 3 stage intake will result in about 20 horsepower with a tune, right? There are dyno sheets all over this forum proving that. And we can also probably agree that catless headers when tuned will net you About another 20-30 horsepower. Again there are dyno sheets everywhere proving that. And with a secondary cat delete, multiple members have proven it will net you 5-10 horsepower. Just with those things you're at around 280 horsepower if not more. It might not be exactly 300 but for the purpose of my article it's close enough

On a dynojet (..and who's dunojet at that?). Let's see you get those numbers on a Mustang where we actually have honest numbers being produced.

I'd say the IM is worth 12-15, and the headers, 16-20. The N52B30 put out 250 stock, and tuned you could POSSIBLY approach 270-280 crank, but that motor already had the 3iM and was tuned for it. You could maybe squeeze another 6, maybe. Then you do the Valvetronic mod and EM's, clean up the exhaust. If you're lucky another 30, IF you're lucky.

So you're looking at 285 crank, max. Now subtract 18% drivetrain loss and what have you got?

18 is a conservative figure, and anyone who's seen my street cars, let alone my race cars, knows I'm a maniac about this, down to micro-shot peening my transmission gears, running silicon nitride bearings, replacing the garbage bearings in the diffs with proper slicone nitride balls and shotpeening the races, and so on.

Trust me, you're in total fantasy land here mate.

[IISevv]

Originally Posted by NiNeTyOne

On a dynojet (..and who's dunojet at that?). Let's see you get those numbers on a Mustang where we actually have honest numbers being produced.

I'd say the IM is worth 12-15, and the headers, 16-20. The N52B30 put out 250 stock, and tuned you could POSSIBLY approach 270-280 crank, but that motor already had the 3iM and was tuned for it. You could maybe squeeze another 6, maybe. Then you do the Valvetronic mod and EM's, clean up the exhaust. If you're lucky another 30, IF you're lucky.

So you're looking at 285 crank, max. Now subtract 18% drivetrain loss and what have you got?

18 is a conservative figure, and anyone who's seen my street cars, let alone my race cars, knows I'm a maniac about this, down to micro-shot peening my transmission gears, running silicon nitride bearings, replacing the garbage bearings in the diffs with proper slicone nitride balls and shotpeening the races, and so on.

Trust me, you're in total fantasy land here mate.

Dude, I'm not here to argue with you. I made it so new 328 owners could have some fun with their cars. I even said in my article that it would add up to about 290 and not 300 and I specifically said some of my numbers may be off and it's completely based off of what I've seen. The point of it is to have fun