1. Testing was performed on a Dynojet dynamometer with SAE correction and a smoothing value of 5.
2. Testing was performed in one dyno session over a matter of just a few hours yielding consistent intake air temperatures and negating any environmental factors. The car remained strapped to they dyno while the manifolds were swapped.
3. No changes to the tune were made during testing yielding consistent boost, timing, and AFR’s.
4. Standard Buschur and MAP exhaust manifolds were used for this testing, no changes were made and no additional work was performed.

It is also important to note that two unbiased parties (customers of both MAP and Buschur) witnessed this entire test and will confirm that every precaution was taken to ensure that these results were not skewed in any way. Now on to the results, please click the graph for a larger view.

In conclusion, it is evident that the additional time and effort we put into our Rev2 ported exhaust manifold yields a substantial increase in performance over the Buschur racing manifold. While I have the utmost respect for David Buschur and what he has done for this community, it is clear that even with 20+ years of experience he is not infallible.

This is what the car’s owner had to say:

A few years ago I picked up a buschur ported exhaust manifold and SS o2 housing based on some advertised gains and since then I have been extremely happy. Credit NEEDS to be given that this is a good basic port job and the silver ceramic coating that comes on it is IMHO the most durable I’ve seen thus far. Seriously, thank you David for an awesome product. I’ve had it for TWO YEARS and its proven itself over and over, performing very consistently. I have a ton of other Buschur parts, so if someone wants to call me a MAP fanboi or nutswinger, they better call me a Buschur fanboi and/or nutswinger too

Still, I have seen Bob@MAP’s port work have had him do several parts on my car since; when I got my BBK he ported the turbine housing and compressor cover beautifully, and then when my head was off earlier this summer he gave it their stage3 treatment. I’ve seen his manifold portwork first hand and I’ve seen the various discussions regarding the different theories of porting various parts of the inlet and outlet tract and what makes more power, better spool-up, etc etc. Needless to say I was still curious.

When the opportunity arose to do a scientific comparison between the two, I was game and volunteered immediately. I wanted to be as thorough as possible and get as much data as we could, as I knew this was heading into passionate waters. I have a degree in Physics and spent a TON of time in scientific laboratories compiling data, plotting charts, and making conclusions based on the data. This is how I wanted to do this test, and that’s what we did. I run mrfred’s boost corrected, ecu-controlled boost control with the GM BCS and tuning was originally done by shane @ DB Performance. I turned down the timing across the board so as to let the car be in a very safe state, not right at the edge of the limits timing-wise (12 days ago this car put down 480whp on this dyno at full timing, under similar weather conditions). I think the graphs below show that we did our very best to keep things as consistent as possible from run-to-run.

All runs were performed with aquamist hfs-1 on, running a 50/50 mixture of VP M1 methanol and distilled water.

Actual data from actual comparo runs presented above:

Note that my boost numbers are slightly higher than MAP’s, since we used different map sensors, and mine was not zero’d out before the test.

So there you have it. Depending on the run, you’ll see that the buschur port job nearly equal but slightly out-done by the more extreme MAP port job, but is consistently bested by the MAP manifold above 7000rpm. On average, gains in the midrange were around 4-5whp and up top they were on average 8whp.

Full mod list:
Buschur Racing 3″ TBE w/ bullet testpipe
Buschur Racing Intake w/Perrin filter
BR Race FMIC
Custom LICP
BR Upper IC Pipe
OEM IX BOV
AMS/TMS L19 headstuds
MAP Stage 3 Ported Head
Kelford 272 cams
GSC beehive valve springs
BR Ported/Coated Exhaust Mani
CBRD BBK turbo
MAP ported/coated turbine housing
BR SS O2 Housing
BR Ported Intake Manifold w/ EGR delete
BR 65MM TB
Walbro 255HP fuel pump
4x Kracka Vent setup w/ ebay catch-can
Buschur dipstick retention spring
Aquamist HFS-1 Alky Injection Kit (1.0 + .9mm jets)
FIC 1050cc injectors
GM BCS
Evo X MAP sensor
Innovative LC-1
GM IAT
Tephra v7t6 ROM w/EGT Elim, Direct boost mods

In the end, I left the MAP manifold on my car. Being an impartial (but loyal) average car guy, I want the part on my car that makes the most power. IMHO, the MAP manifold consistently makes more power. I saw it with my own eyes, felt it on my own car. The buschur unit has served me well and I would recommend it to anyone if the MAP manifold was out of stock.