Ok, the end all of 325 vs 328 speed-wise

[JohnnyWash1]

Because of a recent thread about the differences between these two models, my buddy and I decided to do a few runs tonight to shed some light on this subject. Please feel free to add your experiences.

My Car
1994 325is 106K miles
Turner Chip (really helped with torque/midrange)
ECIS intake (didn't do anything noticeable)
Kosei K1 wheels (again, torque)


His Car
1996 328is 150K miles
SS exhaust (only performance mod)
18" BBS RK wheels (heavier than mine by a bit)

To ensure proper results, we ran from the same speed in the same gear with the same amount of gas in the tank (about 3/8ths tank). He weighs about 215lbs and I weigh 208.

1st run: 30-80
Dead even

2nd run: 30ish-110
Dead even

3rd run: 65-100Dead even

4th run: 15-110ish
Dead even, with me pulling slightlyat high speed (>90)

5th run: 65-up (5th gear only)
He walked me.

There you have it. In most of the runs, I was honking three times and on the third we ran. To make it fair (I'm a science major; I'm more interested in accurate results), the latter runs were done with the same system but I would wait until I saw his car lift in the front to hit it (just to make sure I wasn't jumping him). If you watched the race, you would say it was very even at the start. There was one run it wasn't, and that was obvious because I jumped ahead but couldn't keep pulling. The moral is with a few well placed mods a 325 can keep up with a 328. I believe that I'm making more hp higher in the rev range, so I pull better at higher rpms. He definitely pulls down low, though. With the chip, fuel cutoff on my car is 7K, but I was shifting at about 6700-6800. If you have stories or questions, feel free to post.

[coldblooded 328]

clearly, these are the rigged results coming from the 325 owner, lets see what the 328 owner has to say. :D

i kid, seems to be a very good matchup with the mods and the results are what i would expect.

[JohnnyWash1]

Lies! Tan wanted the 328 to win!

[stowe9man]

Of course the 328 is going to be marginally faster. However, there are always variations even with cars of the exact same model and year. I don't doubt your results, but I am guessing you might have faired slightly better than what most people would experience.

[JohnnyWash1]

Mine is the red one and my friend has the black one (the silver car is owned by the first guy to post in this thread. He clearly loves his front plate)

http://i45.photobucket.com/albums/f60/johnnywash1/102_0222.jpg

[JohnnyWash1]

Of course the 328 is going to be marginally faster. However, there are always variations even with cars of the exact same model and year. I don't doubt your results, but I am guessing you might have faired slightly better than what most people would experience.

I think given the conditions of the race, the results make sense. His car has more miles, no real performance mods, and heavier wheels. We basically eliminated his advantage.

[turbodefrost]

yeah i was pretty suprised how dead even we were when starting at around 15. But it all makes pretty good sense. my wheels are by no means lightweight, and exhaust is the only thing I have done performance wize (which i don't think made any difference). I think his chip, intake, and lighter wheels made enough difference to make us virtually even. Of course i was hoping to pull more on him but this is nice to know.
At least you got walked on our 5th gear pull :D that's where my low-end torque advantage helped.
My car has felt slow lately tho... I think i need to replace a few things... it seems like it's hesitating :(

Just wait till i get the 3.15 LSD, shark injector and M50 manifold!!! then we'll see about who wins

[e36bmdub]

dont forget m3 cams, and fan delete mod, and intake for the ultimate m52 setup

[JohnnyWash1]

Boo to your mods

[JohnnyWash1]

dont forget m3 cams, and fan delete mod, and intake for the ultimate m52 setup

You shush. He needs a huge rear wing and 20" rims.

[turbodefrost]

Boo to your mods

It really isn't the end all thread cause of our differences in mods. We need to do stock vs. stock. we should find a bone stock 325 to race tan. then we'll see.

and Yes i forgot to mention the cams, fan delete and CAI... and of course others but the ones i mentioned are next on the list for me. Recently i've bee more focused on suspension.

How bout we throw in a few corners into our race :evil2

edit: oh yeah and my clutch also is horrible compared to jon's so of course that can make a difference... i've got all the excuses i need!!!

[coldblooded 328]

It really isn't the end all thread cause of our differences in mods. We need to do stock vs. stock. we should find a bone stock 325 to race tan. then we'll see.

and Yes i forgot to mention the cams, fan delete and CAI... and of course others but the ones i mentioned are next on the list for me. Recently i've bee more focused on suspension.

How bout we throw in a few corners into our race :evil2
word, suspension > straight line mods any day.
i want to run jon this weekend and see how that goes.

[e36bmdub]

haha i love it, im down for a run this weekend too, i'll make the trip up to WA..hah maybe not cuz i only have 80k miles and i wanna keep it that way for a while...lol but it would be funny to have 3 m52's against an m50 ;)

[JohnnyWash1]

Ok ok guys, calm down. It is the end all because it demonstrates what is necessary to make the cars even. It doesn't say much if one car is faster. That much is obvious. Now we have a case where the cars couldn't be closer. That says plenty.

[JohnnyWash1]

haha i love it, im down for a run this weekend too, i'll make the trip up to WA..hah maybe not cuz i only have 80k miles and i wanna keep it that way for a while...lol but it would be funny to have 3 m52's against an m50 ;)

Do it! I'll run you all! :devillook

[e36bmdub]

haha


Do it! I'll run you all! :devillook

[JohnnyWash1]

Hellrot is the fastest color.

[e36bmdub]

i agree :)

[le36x3r1cx]

I don't understand how a stock 328is could be so much faster than a chipped 325is assuming equal drivers.

A stock 328is is I believe 190hp/207lb at the crank correct.

And a 325is is 189hp/181lb at the crank, a TMS chip adds 22hp and 20tq so that should be 211hp/201lb, with a 21hp advantage and only 7 tq disadvantage shouldn't the 325 be just as fast or faster, or do the cars just make peak horsepower and torque at different points which makes all the difference?

[turbodefrost]

Ok ok guys, calm down. It is the end all because it demonstrates what is necessary to make the cars even. It doesn't say much if one car is faster. That much is obvious. Now we have a case where the cars couldn't be closer. That says plenty.
ah i see what you mean. Even thought they're heavy i still love my rims, it's worth the extra weight...

I'm getting a little uneasy about dumping all this money into an engine with 155k miles on it tho... i know it can "run" for a lot longer but performance will start dwindling and things will start going wrong soon... that's why i'm sticking more to suspension mods, those are really what matter anywyas... i'll keep telling myself that...

[turbodefrost]

I don't understand how a stock 328is could be so much faster than a chipped 325is assuming equal drivers.

A stock 328is is I believe 190hp/207lb at the crank correct.

And a 325is is 189hp/181lb at the crank, a TMS chip adds 22hp and 20tq so that should be 211hp/201lb, with a 21hp advantage and only 7 tq disadvantage shouldn't the 325 be just as fast or faster, or do the cars just make peak horsepower and torque at different points which makes all the difference?
a stock 328is isn't faster than a 325is with the TMS chip, that's what we've just pointed out... but i'll never let jon down about my 5th gear ownage :D

[le36x3r1cx]

http://www.youtube.com/watch?v=mKHSxry92x4

that vid seems to show otherwise as the 328 creams the 325

[JohnnyWash1]

I don't understand how a stock 328is could be so much faster than a chipped 325is assuming equal drivers.

A stock 328is is I believe 190hp/207lb at the crank correct.

And a 325is is 189hp/181lb at the crank, a TMS chip adds 22hp and 20tq so that should be 211hp/201lb, with a 21hp advantage and only 7 tq disadvantage shouldn't the 325 be just as fast or faster, or do the cars just make peak horsepower and torque at different points which makes all the difference?

Never pay attention to advertised numbers. Peak numbers, as you suggested, are highly suspicious and don't mean much. Plus, as always, your results may vary.


ah i see what you mean. Even thought they're heavy i still love my rims, it's worth the extra weight...

I'm getting a little uneasy about dumping all this money into an engine with 155k miles on it tho... i know it can "run" for a lot longer but performance will start dwindling and things will start going wrong soon... that's why i'm sticking more to suspension mods, those are really what matter anywyas... i'll keep telling myself that...

Whatever, get the intake.



a stock 328is isn't faster than a 325is with the TMS chip, that's what we've just pointed out... but i'll never let jon down about my 5th gear ownage :D

I think the chip may not be enough. Put the bottlecaps on and we'll see.


http://www.youtube.com/watch?v=mKHSxry92x4

that vid seems to show otherwise as the 328 creams the 325


Yeah, street races are just that--highly subjective. This is what I experienced and I think it makes sense.

[turbodefrost]

http://www.youtube.com/watch?v=mKHSxry92x4

that vid seems to show otherwise as the 328 creams the 325
:dunno maybe my car needs help :(

[JohnnyWash1]

:dunno maybe my car needs help :(

Nah, it's fine.

[Jasonv8z]

I don't understand how a stock 328is could be so much faster than a chipped 325is assuming equal drivers.

A stock 328is is I believe 190hp/207lb at the crank correct.

And a 325is is 189hp/181lb at the crank, a TMS chip adds 22hp and 20tq so that should be 211hp/201lb, with a 21hp advantage and only 7 tq disadvantage shouldn't the 325 be just as fast or faster, or do the cars just make peak horsepower and torque at different points which makes all the difference?


The TMS dyno tends to exaggerate things. I don't think people see anywhere near 21hp gain from their chip, but its just my opinion.

Acceleration is all about weight and area under the HP curve between shift points, not peak hp numbers. If you look at the dyno charts, you'll see the 328 stays around its peak hp over a wider rpm range. This is why the 328 is usually faster despite similar HP ratings. They might dyno a little higher too, naturally.

[turbodefrost]

ok jon and I will try trading wheels for a few runs just to see whether the weight makes any difference! This is interesting

[deanbruhn]

There really should be some dyno comparisons for everyone to look at so they can see where the power is different accross the two power bands of the motors. More torque usually means more low end power, if these boys would have done a start from a stand still they probly would have seen the 328 really showing its power advantange. The intake being replaced on the 325 would have let it breath better giving it a chance to perform better in the higher rpm's this more than likely offset the low end power that the 328 had going for it.

Unsprung weight loss will provide the most bang for the buck in wieght savings (wheels, drive train, suspension anything that has to move to get the car moving). I always laugh when I see guys talking about pulling out rear seats and putting carbon fiber hoods on yet they put these big ass heavy wheels on.... *shakes head* So the change in wheels will probly show its face if there really is a difference in weight.

My performance motorwork usually is centered around 2 wheeled toys, we have a saying in those circles. "There's no replacement for displacement." Its the truth, the 325 stock would have lost to the 328 its just how it is. Having a larger displacement start for any motor is positive unless you are trying to race and need to fit in a CC class for racing.

Its so wierd for me watching this forum, in the motorcycle world you see people doing way more headwork, and custom cam profiles, intake and exhaust work. All of these things can have a huge effect on how each part of the motor works. Hell in just changing your exhaust and intake you can have a huge effect on your how your car works, in positive and negative ways. By just simply adding a high flow intake and exhaust you actually will lose power in the bottom end and gain it in the top. Im not sure about any of the cam spec's in these motors but I can tell you a properly tuned exhaust with a custom ground cam, tailored to the power range you want to exagerate or smooth out can make an amazing difference. But this is coming from a guy with a Harley Sportster putting just over 100 HP to the ground....

[e36bmdub]

haha yea i agree its pointless to remove seats and add carbon fiber things...althought i love carbon fiber...i wouldnt put it on a bmw, unless its black...only carbon fiber im going to add on my car is the engine cover from bavauto..
although i am going to be putting some 18" staggared asa ar2's on soon...idc if i lose performance, their lightweight anyways...but its one non performance mod i want for sure!

[ishkabobble55]

e36bmdub, i live pretty close to cleveland, you want me to come over and show whats up?! i think i could take that 328 of yours. lol:redspot

[sixspd]

There really should be some dyno comparisons for everyone to look at so they can see where the power is different accross the two power bands of the motors. More torque usually means more low end power, if these boys would have done a start from a stand still they probly would have seen the 328 really showing its power advantange. The intake being replaced on the 325 would have let it breath better giving it a chance to perform better in the higher rpm's this more than likely offset the low end power that the 328 had going for it.

Unsprung weight loss will provide the most bang for the buck in wieght savings (wheels, drive train, suspension anything that has to move to get the car moving). I always laugh when I see guys talking about pulling out rear seats and putting carbon fiber hoods on yet they put these big ass heavy wheels on.... *shakes head* So the change in wheels will probly show its face if there really is a difference in weight.

My performance motorwork usually is centered around 2 wheeled toys, we have a saying in those circles. "There's no replacement for displacement." Its the truth, the 325 stock would have lost to the 328 its just how it is. Having a larger displacement start for any motor is positive unless you are trying to race and need to fit in a CC class for racing.

Its so wierd for me watching this forum, in the motorcycle world you see people doing way more headwork, and custom cam profiles, intake and exhaust work. All of these things can have a huge effect on how each part of the motor works. Hell in just changing your exhaust and intake you can have a huge effect on your how your car works, in positive and negative ways. By just simply adding a high flow intake and exhaust you actually will lose power in the bottom end and gain it in the top. Im not sure about any of the cam spec's in these motors but I can tell you a properly tuned exhaust with a custom ground cam, tailored to the power range you want to exagerate or smooth out can make an amazing difference. But this is coming from a guy with a Harley Sportster putting just over 100 HP to the ground....
Why is there this common misconception that adding a freer flowing intake and exhaust will make you lose power on the bottom end. This may have been true in days of old and carburated vehicles. But modern day bmw's can adjust air/fuel ratio and timing to accomadate extra flow.

[Dejo325i]

I'm putting just the S50 intake cam on my M50, in theory it should really improve the torque down low and mid, but not so much gain up top coz the exhaust cam is stock.

[JohnnyWash1]

There really should be some dyno comparisons for everyone to look at so they can see where the power is different accross the two power bands of the motors. More torque usually means more low end power, if these boys would have done a start from a stand still they probly would have seen the 328 really showing its power advantange. The intake being replaced on the 325 would have let it breath better giving it a chance to perform better in the higher rpm's this more than likely offset the low end power that the 328 had going for it.

Unsprung weight loss will provide the most bang for the buck in wieght savings (wheels, drive train, suspension anything that has to move to get the car moving). I always laugh when I see guys talking about pulling out rear seats and putting carbon fiber hoods on yet they put these big ass heavy wheels on.... *shakes head* So the change in wheels will probly show its face if there really is a difference in weight.

My performance motorwork usually is centered around 2 wheeled toys, we have a saying in those circles. "There's no replacement for displacement." Its the truth, the 325 stock would have lost to the 328 its just how it is. Having a larger displacement start for any motor is positive unless you are trying to race and need to fit in a CC class for racing.

Its so wierd for me watching this forum, in the motorcycle world you see people doing way more headwork, and custom cam profiles, intake and exhaust work. All of these things can have a huge effect on how each part of the motor works. Hell in just changing your exhaust and intake you can have a huge effect on your how your car works, in positive and negative ways. By just simply adding a high flow intake and exhaust you actually will lose power in the bottom end and gain it in the top. Im not sure about any of the cam spec's in these motors but I can tell you a properly tuned exhaust with a custom ground cam, tailored to the power range you want to exagerate or smooth out can make an amazing difference. But this is coming from a guy with a Harley Sportster putting just over 100 HP to the ground....


The run in 5th gear was meant to show the torque difference. Also, we ran from 15mph, which is basically a good way to show any torque differences while eliminating the driver as a variable.

[deanbruhn]

Why is there this common misconception that adding a freer flowing intake and exhaust will make you lose power on the bottom end. This may have been true in days of old and carburated vehicles. But modern day bmw's can adjust air/fuel ratio and timing to accomadate extra flow.

Its not about adjusting the air to fuel ratio, if you have ever spent time on a flowbench with a head in any naturally aspirated motor you can see why it is that way. Going by your therory if you just open up the ports as much as possible you will get maximum flow all the time. It doesnt work this way, when opening up the intake and exhaust you lose air velocity, which causes better fuel atomization and a stronger burn. Turbulence and velocity in a motor will provide you low end torque, high flow in a motor will provide you with top end power. The trick is finding the balance that works for the power you are trying to achieve. A good FI system can help compensate a little to smooth out some of these problems and give you a bit more balance, but the reality is its all a matter of physics and you cant change the physics of the air at that point. Your only fiddling with things trying to smooth out the problem.

[325iklu]

I have a little something to add.

Back when i was driving my Talon tsi I raced a 328 and beat him by a car or so. (MODS 328:exhaust. Talon:boost controller

I rebuilt the motor in my non-vanos 325i. Did some free mods to that and raced the same Talon.

The 325i had the Talon beat by 4 cars or so. All cars manual and all races from a 65mph roll.

Who knows some 325s might be factory freaks and some 328s might be built on a friday. :dunno

[jordanmgregory]

I have a little something to add.

Back when i was driving my Talon tsi I raced a 328 and beat him by a car or so. (MODS 328:exhaust. Talon:boost controller

I rebuilt the motor in my non-vanos 325i. Did some free mods to that and raced the same Talon.

The 325i had the Talon beat by 4 cars or so. All cars manual and all races from a 65mph roll.

Who knows some 325s might be factory freaks and some 328s might be built on a friday. :dunno

Which diffs were on the 325 and 328?

[LuvMy328is]

dont forget m3 cams, and fan delete mod, and intake for the ultimate m52 setup
+


Just wait till i get the 3.15 LSD, shark injector and M50 manifold!!! then we'll see about who wins
= me

:D :redspot
~Phil

[turbodefrost]

+

= me

:D :redspot
~Phil
yeah your mod list in your sig is my ultimate list of mods for my car. You have any threads with pics/vids/dynos?

[325iklu]

Which diffs were on the 325 and 328?

328 stock ratio and my stock 2.93 ratio.

[turbodefrost]

I got a lil something to add here.

I bought a talon when i was rebuilding the motor in my NV 325i.

Talon had free mods and a boost controller. I raced a local guys 328is with a Exhaust and a K&N filter. I had him buy a car and a half by 120.

I finished my rebuild in the 325i with some free mods. (de-baffled air box, coolant TB bypass, advanced intake and retarded exhaust cam by 3degrees.)

I raced the Talon had had it beat by 4cars or so by 120. All cars are manual and from a 65mph roll. :dunno

Maybe there were some factory freak 325s and some 328s that were built on a friday. Who knows
??? uh yeah you just told us this in post #35...

[325iklu]

^ oops. EI froze and i didnt see it so i reposted it sorry. FIXED

[LuvMy328is]

yeah your mod list in your sig is my ultimate list of mods for my car. You have any threads with pics/vids/dynos?

Here's my M50 Manifold Swap (http://forums.bimmerforums.com/forum/showthread.php?t=544874) + other mods, thread. :thumbup:
My Dyno was showing 200whp before the FDM, ASC delete or the software. :)

Next step for me is the S/C :evil2

~Phil

[JohnnyWash1]

Sweet Saab.

[Corky325]

I used to have just intake and exhaust and i can vouch that it takes away the low end power.

[schwarzII325is]

im not adding an intake to my car just cause i see it to be pointless...as an owner a 325..everyone knows the torque down low is lacking a little, until it hits 2k-6.5k (my car). Why would I compromise my low end torque for high end torque, when I don't even have enough low end torque to begin with?

sound seems to be the only justification

maybe my view is skewed, correct me if im wrong..

thanks

[stowe9man]

I really wish e36's had some more low end torque. My dads '86 Monte Carlo SS with its pathetic 180hp 305 can dust the BMW from a stop. This is probably due to the 3.73 posi rear end that the Monte Carlo comes with. At least the BMW leaves it behind after about 50 or so. I think the Monte Carlo tops out at like 120 :rofl

[bmxludwig]

"There's no replacement for displacement." Its the truth...

*Cough.. supercharger, *Cough.. turbo, * Cough.. nitrous,

[LuvMy328is]

im not adding an intake to my car just cause i see it to be pointless...as an owner a 325..everyone knows the torque down low is lacking a little, until it hits 2k-6.5k (my car). Why would I compromise my low end torque for high end torque, when I don't even have enough low end torque to begin with?

sound seems to be the only justification

maybe my view is skewed, correct me if im wrong..

thanks

It depends on your driving style, you are correct in your thoughts. I sacrificed some low end by swapping to the M50 manifold. Since I tend to drive lots of highway and usually have don't "contests of speed" from a standing start, high end horsepower is why I have done the things I have. From a stand still a stock 328 would prolly be about even with me until around 30-40ish. Then from 40+ I would walk away from it or at highway speed it wouldn't even be close. I know this :evil2 :devillook
~Phil

[schwarzII325is]

im more of a city driver, since I'm 17 and don't have any need to travel on the high way, so im opting out of those low end torque drainers..although they sound nice. Most of my driving is limited to the 0-55 speed limit zone.

[JohnnyWash1]

im not adding an intake to my car just cause i see it to be pointless...as an owner a 325..everyone knows the torque down low is lacking a little, until it hits 2k-6.5k (my car). Why would I compromise my low end torque for high end torque, when I don't even have enough low end torque to begin with?

sound seems to be the only justification

maybe my view is skewed, correct me if im wrong..

thanks

I didn't notice any torque loss when I installed my ECIS. I didn't notice any horsepower increase either.

[bmxludwig]

im more of a city driver, since I'm 17 and don't have any need to travel on the high way, so im opting out of those low end torque drainers..although they sound nice. Most of my driving is limited to the 0-55 speed limit zone.

It is not like it totally diminishes ALL of your torque, there is just a small loss compared to the higher hp. You hit redline atleast twice on your way to 55 if you are racing.