MPI Supercharger Dyno Results

[dynotechjim]

Art I like the boondocker controller--the Boondocker guys Rocky and Dave were here dyno tuning with their turbo apex (posted on my website up to 350 HP). And even though we're overspeeding your SC compressor to the moon, you still made 240 plus HP on a mix of race gas and pump gas for maybe 15 sec at WOT. Now if we can drop your top end A/F ratio from 14/1 to 12.5/1 you might make even more HP. More fuel pump capacity (like something for a 5.3 liter chevy V8!!) and a Boondocker controller would be your best bet in my opinion.
Also my opinion is that the innovate wide band A/F ratio meters and other wide bands are very slow to respond to actual changes. Compare my Superflow dyno machanical A/F ratio readings to the LAMAF1 column on the dyno data on DynoTechResearch (recorded off of our LM1 innovate tied into the dyno software). And understand that our mechanical fuel flow and airflow meters are not instantaneous, but WAY faster than wideband. If you tune your Boondocker in the field with LM1 do it with race gas and do it very gradually, work your way up to full throttle understanding that it will take several (many) seconds for your innovate A/F to report the actual conditions.

 

[SPEED]

Thanks for that Jim but you know I'm a sissy, I have to much faith in the dyno, I'll make the changes and bring it back up to your place, That 7hr ride is a lot quicker than 40 hr rebuild.

 

[Srxspec]

Jim, on Monday I will make you a cheat sheet with RX-1, Apex, and Phazer gear reduction numbers! Max compressor wheel speed is 150,000 rpm for the Stage 1 unit (which is what was tested on this particular sled). The 26/24 pulley setup sets it right at max compressor speed at 11,000 engine rpm.

Here's a post talking about blower speed vs engine rpm and some different pulley setups.

http://www.ty4stroke.com/viewtopic.php?t=31555&highlight=

 

[SPEED]

Allen, If I'm not mistaken we should be in a safe zone with compressor speed based on the 26/24 configuration as long as we keep it down around 10400 rpms,

 

[Srxspec]

Art, yes we should be fine at that RPM setting. My thoughts are that the sled could possibly use a larger intercooler from my low and high elevation riding last season. The MPI intercooler is roughly the same size as the Bender turbo unit was, but the Bender system also runs a cooler under the tunnel to help cool the air charge. I haven't had a chance to look into a slightly oversized intercooler, but it's something that if or when I find the time I'd like to do! LOL! I think a slightly larger one would benefit the lake racer who makes back to back runs or anyone who is pushing the limits of the compressor.

 

[HAMMER]

Allen -- Looks like my $30 VDO boost gauge is fairly accurate, about 0.3lb high the way I figure it. My azz dyno was pretty fricken accurate on this setup too, clutched it for 10,500-10,800 with the supertips I got from you and that's where it needs to be (confirmed by dynotech). I was only 0.4hp low on the guess of 230 at 10lbs (confirmed by dynotech) my azz dyno is a little on the conservative side...lol

Atmospheric Pressure = 14.7psi +11psi

Absolute Pressure = 25.7 (243.4hp)

Atmospheric Pressure @ 8000ft feet = 11psi +11psi

Absolute Pressure = 22psi

Approximate Pressure Loss = (25.7-22) = 3.7psi

(3.7/25.7) = 14.3% pressure loss at 8,000 feet

243.4 x .143 = 34.7hp

243.4 - 34.7 = 208.7hp at 8,000 feet

Dyno indicated 11.3 x .143 for 8,000ft = 1.6psi

11.3 - 1.6 = 9.7psi (10psi indicated on my gauge)

Jim -- It says "corrected" to 15°C (59*F) and 0.1013 Mpa (14.7 PSI) at the bottom of that compressor map for whatever that's worth. The dyno report shows that power will start to fall off after 0.20kg\s (330CFM), which is pretty much what the compressor maps is telling us will happen. Rotrex's spec sheet shows 0.18kg\s (294CFM) as its max flow rate.

 

[SPEED]

Hammer I am running the same boost gauge you have( actually copied off of you on that) If you don't mind could you direct me to your post on the fan set-up you have and as far as air intake , did you relocate to draw outside air. Any help would be appreciated
Art

 

[dynotechjim]

Hammer the CFM reading on my dyno sheets are SCFM (Art's dyno session was close to standard) so at 20 deg F compressor intake temp the compressor will flow more SCFM of air making it more critical to maintain fuel pressure.
Alan I would appreciate a cheat sheet like that. When I dyno tested the new Phazer I couldn't get the actual reduction ratio anywhere, so I just kept altering the dyno ratio up and down until the sled's tach matched the dyno tach.

 

[TurboJamie]

I think alot of us here are very impressed with these numbers! Its amazing what this clean little unit can do. I think we can all benefit from a little better fuel pump I will definately go for one on my setup now even at 1:1. I also have way more interest in the Excell exhaust now well enough to order one! I wasn't sure before hand if the lack of backpressure would hurt this thing or not guess we know now!!!

Thanks for Taking your sled there Art I really appreciate the run it helps us all out! Also awesome to know that MPI is honest with their numbers on their kits, its nice to see that from aftermarket companies when so many 2 stroke motor guys BS everything another reason the 4 stroke rules.

 

[HAMMER]

 

[SPEED]

Thanks for the info Hammer , I already put BPE hood scoop on as well as louvre'd inspection plate on the underside, should flow a whole lot more air thru underhood area. I shouldn't be dealing with the snow amount on the hood ( here at sealevel we're not that lucky) so I believe I am going to go thru the top some how and try to draw as much cold air as possible.
FYI Jim's scoop is outstanding fit's very nice.
Thanks again Art

 

[Srxspec]

If anyone wants an Apex hood with a whole already in it let me know! Did this experiment up in high elevation last season! It needs a little touch up as the hole cut in it was done out in the middle of no where after being fed up with not being able to get any boost built and no intake air to feed the charger. It worked much better after putting the air filter above the hood, but dang it was ugly!!

 

[SPEED]

OK Allen I,ll bite , how much for that ugly hood (it's even the wrong color) ?

 

[Srxspec]

Ugly hood $75 plus shipping. I have someone who has PM'd me on it as well.

 

[millstreet]

dynotechjim-"scary hot air" he's right if you make several back to back hard pulls with these-the intercooler gets HOT to the touch-and the performance drops off noticably(on the azz meter)