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View Full Version : disapointed with power what is up with that



partouza
07-08-2004, 04:54 PM
hi i have modified my 93 325 and i am not happy with results. last year i bought the car in may and it had only a remus exaust.ihad also done a compression test and got 210-200 through all the cylinders. i bought a turner chip and tried it at the drag strip my best run was 15.33 at 89mph and 2.25 60foot.
a week later i lent my car to my brother and he $shift my car. i wanted to kill him but shit happens. my mecanik open the engine and found all the exaust valves bent they had hit the pistons.it was repairable so he changed all my valves cleaned and machined the head put a new head gasket and put it together.this year i put in 3.23 lsd, fan delete,ecis cold air intake, and m3 cams with turner chip.i took it to the drag strip last week and my best run was 15.22 93mph and 2.35 60 foot.i friend of mine was with me with his 99 328i with some small mods like pullys, oils, and his best run was 15.09 at 94 mph. i was pretty disapointed so i went home and did a compression test and found 170-180 through all the cylinders.by the way my engine is running healthy and feels stronger than ever i also have been doing very frequent oil changes because i had noticed alot of sluge build up in the engine when i bought it, now it is much much cleaner.so what is up with this shouldn't i have more power with all this mods. what could be wrong. shouldn't i have a little higher compression after machining the head. please some expert feedback.

T-Rex
07-08-2004, 05:40 PM
depends on how much was taken off. BMW replacement head gaskets are 2.05mm vs 1.75mm stock. If you machine the head .012", then you will have the exact same clearances as before. The only thought I could offer is that maybe you mechanic only milled the head by .006" or something to that extend so that there is a little more space. Even still, .01" only means .1 compression point, so this still doesnt account for your lower than usual compression. Wish I could be more of a help, have you brought this issue up with the mechanic who did the work?

Bremsen
07-08-2004, 05:44 PM
Sounds like something isn't right. My best time so far is 15.2 and I don't have the cams.

You should probably put it on a dyno w/ a/f to see what the software is doing. My 0.02

morea328i
07-08-2004, 06:41 PM
Maybe you are just not good at drag racing....

Let your buddy that has the 99 drive yours and see what time he gets...

:)

DeanP
07-08-2004, 08:38 PM
I am not an expert at Turner Chips. I do know that, for example, if you take a domestic V-8 and put a Hypertech chip in it and then later upgrade the cam you will probably loose power. The chip was programed based the air and fuel flow of the stock set-up. It doesn't know you installed a better one. Maybe Turner Chips are similar? It doesn't know what to do with the extra air and it keeps dumping the same amount of fuel and you might be running real lean.

T-Rex
07-08-2004, 08:41 PM
When he said he got a new chip, I figured he was talking about the turner chip designed for the M3 cams.....what chip do ya have in there?

Stylin
07-08-2004, 09:03 PM
a lot has to do with the driver with the quater mile runs so maybe it really isnt the car.. i know im not an experienced dragger and would probably run crappy times with my car i wouldnt be happy with either. BUT your time isnt that bad.. i mean the car is going on 11 years old and 15 secs is probably the correct time for a 325.

Wayne@PelicanParts
07-09-2004, 09:28 PM
Agreed - the driver has a lot to do with it, but he also has lowered compression here from original. Compression numbers can change according to the phases of the moon (not literally), but check out this article for more info on that:

http://www.pelicanparts.com/bmw/techarticles/Borrowed/mult_engine_rebuild-1.htm

However, I would guess that your machinist installed the new thicker gasket (recommended by the factory manuals), but didn't machine enough off of the head, so he might have actually lowered the compression on you. That's just a guess, don't go accusing him, but I think you might want to ask him how much he took off, and which gasket he used...

Another argument for doing it yourself...

-Wayne

Serious
07-09-2004, 10:21 PM
that time is about right for your car and mods.

maybe get some stickier tires.

what size wheels and tires are you running?