[Biginboca]

I was looking back over the evolution of my build and came across a time slip from 1 year ago. I was comparing to my most recent dragy log to see how things have progressed and thought some of you guys might find this interesting.

I havent gone back to the track for a second time slip yet. The dragy satellite timer is supposed to be within a few 1/100’s on every comparison test I’ve seen so I’ve been using it only for the last year. The track is 45 mins away and cost $25 per visit so I’ve just been testing with Dragy on a deserted road in the part of Mexico right near my house

So here’s the 2 runs I’m comparing and they are typical of several passes on each set up:

On the left it was 65 degrees and prepped surface of dragstrip in March 2018.

On the right it was 57 degrees and normal asphalt road in March 2019.




Mods for the first run...

AFE Intake Scoops
K&N Drop In
Charcoal Delete
Rev Motoring Silicone
West Coast Riots Big Bore Throttle Body
3 Stage Intake
MILVs
AA Headers
3.73 Diff
VMR V710 Wheels 18x8.5fr and 18x9.5rr
Hancook Ventus V12 Tires (225fr/275rr)
BPC Remote Tuning for 3SI, Headers, and MILVs with 7500rpms redline

Changes made since then for second run...

-Add Dinan Ram Style Intake from Bumper to Airbox
-Replace 3” Rev Silicone Tube with 3.5” Aluminum/Silicone Tubing
-Replace Big Bore N52 Throttle Body (80mm) with N54 Throttle Body (77mm)
-Replace 3SI with N54 Intake Manifold
-Replace Secondary Cats with Supersprint Test Pipes
-Replace Stock Muffler with AA Muffler
-Replace 3.73 diff with 3.91 diff with LSD
-Replace VMR Staggered wheels with Apex Arc 8 18x9 square wheels
-Replace Ventus tires with Michelin PS4S tires (255/35 square)

Here’s a few observations...

60’ was substantially better at track last year likely due to prepped surface. If last months run was same 60’ as at the track then it would likely be a ~13.5 or better time.

Look at those trap speeds! The 1/8 mile was 6mph faster and the 1/4 mile was 5mph faster on the new run. This shows a very significant power gain to me, seemingly much more than those new mods should even allow. This is probably due to some weight loss from those mods also contributing beyond just their power gains.

[E90SRB]

How come you replaced the 3SI with the N54 unit? My understanding is the 3SI provides much more power down-low that is usable.

[Biginboca]

Originally Posted by E90SRB

How come you replaced the 3SI with the N54 unit? My understanding is the 3SI provides much more power down-low that is usable.

N54 Manifold makes more peak HP at higher rpms (6000-7500rpms). This will get you through your gears quicker than a 3IM if you are able to run your engine through those rpms, what I mean is you need a manual transmission because the auto shifts at a lower rpm.

So N54 although making less power below 5500rpms is actually better acceleration if you have a manual and raise the redline a bit (~7500rpms is what I’m using). When you are pushing your car hard you are not spending time below 5500rpms where the 3IM makes more power. Running through the gears as you accelerate with a manual you will be shifting at redline and you never drop rpms below ~5500 after a shift, so the 3IM making more power in the range under 5500rpms has no edge over the N54 in that scenario. You need power in the rev range you are staying within and the N54 provides more power in that range. The added peak HP of the N54 manifold is always a downshift away so I find it easy to live with, not like it’s something you can’t use anytime you want as you seem to think.

If you have a automatic then I think the 3 stage is better because you can’t maximize the rev range where the N54 manifold is making more power, so the added power the 3IM makes down low serves the automatic tranny car better.

I’ve run both and like the character of the N54 better. It’s linear and builds smoothly to redline, a characteristic of all the great N/A M engines of the past. It feels and behaves a lot like the S54 from the E46M3. Also if you notice I have never posted anything about failed DISA valves, testing DISA valves, or any other DISA issues. (N54 manifold is simple and reliable )