I purchased an '87 325is yesterday. It is in excellent shape for its age and has 251k miles on it. The original owner was an older lady who put 95% of the miles on it. The gentleman I purchased it from yesterday only had it for over a year. It still has the original clutch in it!
I decided today to take it to work and dyno it to get a good solid baseline for the upcoming motor swap. The best I could get out of it was 135.5rwhp/139.9rwhp, which I didn't think was too bad for mileage on the motor.
Next, I yanked the powersteering belt off to see how much hp/tq the pump was taking. This resulted in 137.7rwhp/143.2rwtq.
Dyno graph - removed powersteering
After this, I decided to see how much the silencer inside the airbox was hurting power. It didn't hurt power as much as I expected it would. Power did go up to 138.3rwhp, but peak torque did go down slightly to 143.0rwtq.
Dyno graph - removed internal airbox silencer
Finally, we pulled the airfilter out to make some final pulls. The filter was made by Fram and didn't have many miles on it according to the previous owner. It was clean, so I didn't anticipate much of a gain. However, this proved to be the best "mod", resulting in 141.1rwhp/146.0rwtq.
Dyno graph - removed airfilter
Overall, I was pretty happy with the numbers the car put down. I had heard of some other bone stock "i" motors putting down 140-143rwhp stock, so I wasn't too far off.
Here is a graph comparing how the car came in and what some free, simple mods can do:
Stock vs Free mods
I definitely wouldn't recommend running without an airfilter on the street, but it is something you could remove if you did take your car to the dragstrip and were looking for a slight bump in power. :D
Some other info:
My friend (Jonathan 90 M3) had dynoed his previous car and current car at this dyno, so we got a good comparison of the 325is to an '87 325 and a '90 M3. The graphs were very interesting to say the least. :)
This graph compares the 325i to the '87 325, which had a BAS chip, BMP intake, and an Ansa catback:
Dyno graph - 1987 325i vs 1987 325
Next, I printed out a graph comparing his 1990 M3 to the 325is. The M3 had a GIAC chip and no powersteering.
1990 M3 vs. 1987 325is
I figure you guys would find those graphs kinda interesting comparing the different E30s.
I really don't have much more planned for this motor. I may add a chip, but really don't want to spend anymore money on this car. I'm saving for the motor swap. :) If anyone has a chip they would like me to try, I'll dyno it before and after, and then send it back. This goes for any other mods as well some people may have laying around. It is nice working at a shop where I can use the dyno whenever I have time. :D
Jason
I decided today to take it to work and dyno it to get a good solid baseline for the upcoming motor swap. The best I could get out of it was 135.5rwhp/139.9rwhp, which I didn't think was too bad for mileage on the motor.
Next, I yanked the powersteering belt off to see how much hp/tq the pump was taking. This resulted in 137.7rwhp/143.2rwtq.
Dyno graph - removed powersteering
After this, I decided to see how much the silencer inside the airbox was hurting power. It didn't hurt power as much as I expected it would. Power did go up to 138.3rwhp, but peak torque did go down slightly to 143.0rwtq.
Dyno graph - removed internal airbox silencer
Finally, we pulled the airfilter out to make some final pulls. The filter was made by Fram and didn't have many miles on it according to the previous owner. It was clean, so I didn't anticipate much of a gain. However, this proved to be the best "mod", resulting in 141.1rwhp/146.0rwtq.
Dyno graph - removed airfilter
Overall, I was pretty happy with the numbers the car put down. I had heard of some other bone stock "i" motors putting down 140-143rwhp stock, so I wasn't too far off.
Here is a graph comparing how the car came in and what some free, simple mods can do:
Stock vs Free mods
I definitely wouldn't recommend running without an airfilter on the street, but it is something you could remove if you did take your car to the dragstrip and were looking for a slight bump in power. :D
Some other info:
My friend (Jonathan 90 M3) had dynoed his previous car and current car at this dyno, so we got a good comparison of the 325is to an '87 325 and a '90 M3. The graphs were very interesting to say the least. :)
This graph compares the 325i to the '87 325, which had a BAS chip, BMP intake, and an Ansa catback:
Dyno graph - 1987 325i vs 1987 325
Next, I printed out a graph comparing his 1990 M3 to the 325is. The M3 had a GIAC chip and no powersteering.
1990 M3 vs. 1987 325is
I figure you guys would find those graphs kinda interesting comparing the different E30s.
I really don't have much more planned for this motor. I may add a chip, but really don't want to spend anymore money on this car. I'm saving for the motor swap. :) If anyone has a chip they would like me to try, I'll dyno it before and after, and then send it back. This goes for any other mods as well some people may have laying around. It is nice working at a shop where I can use the dyno whenever I have time. :D
Jason
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