EO2K

iTrader: (37)

Fear not, its like a 2~3 hour job to put the rotrex back on the thing.

I'm sure John installs them on accident while sleepwalking.

18psi

iTrader: (76)

wow, that plot out of n/a BP is nuts. even some supercharged guys have less power and torque than that

....some serious VTAK action going on at 3700

guttedmiata

Let's play nice now...

codrus

I'm curious why Manleys instead of the A beam Carrillos, since it seems like you're unlikely to need the 600hp rating on an N/A motor? Is the 100 grams of weight reduction each just not worth the cost?

--Ian

Midtenn

iTrader: (15)

Its amazing how far you're been able to stretch the BP especially in a reasonably affordable manor (based on the $8k estimate on Facebook). At $8k, it makes the K swap a little more temping for those of us who are constant tinkers. If you want a set it and forget it motor setup and are bound by rules to us a BP, this would be a great recipe. Thank you for giving us so many options for getting to more potential out of an affordable platform.

ctdrftna

iTrader: (1)

Yeah this really put into perspective how economical the k swap is if staying all motor. The stock k24a2 would put those numbers to shame for the same price. But still sick power for a mid compression all motor BP.

Efini~FC3S

iTrader: (4)

Lolz, beat me to it.

I was going to ask if the VTEC switch over was 3600 or 3700rpm?

emilio700

iTrader: (3)

This a repurposed bottom end I bought from a friend. He had a local guy (Advanced Engine Dynamix) build it. They put the thrust bearing in backwards and honed it wrong. It ate itself so we tore it down. Head was junck so we threw it in the trash. Bottom end was salvageable, thus the Manley rods. I think they are actually JE pistons with some lower tension rings than we normally use. I would use a bigger ST with more compression and Carrillo A's as you suggested.

I'll cut/paste something I posted on anther forum:

This is easily a 100hr motor. Fair to make comparisons. The Rotrex + BP combo is the value leader by far when it comes to making power.Take your existing $2500 I/H/E + ECU and add a $4000 Jackson Racing Rotrex kit for 350whp. Done for $6500. Want it to last, add another $3000 for a built long block and run a bit more boost for 400whp @ $10k.

The K swao comes into is own if you are staying N/A and want over 200whp. That can be done for $9-10K.

This 180whp E85 N/A build could be done cheaper. Starting with a bone stock Miata, probably $9K and you would make about 190whp.

K swaps are cost effective as long as you stick with a junkyard long block and are staying N/A. Outside of that a Rotrex +BP makes more power per dollar at anything above about 180whp.

But yeah, milking the last few hp out of a BP has never been cost effective but it does make for a 100hr track motor.

ctdrftna

iTrader: (1)

Yeah i don't mean to take anything away from what you have done for the BP at all. Your the only one i see really developing the engine.

k24madness

iTrader: (6)

I am more impressed by the average HP of about 176-178 from 6,500 to 8,000 than the peak of 180. Having that kinda power on tap through the entire rev range is what wins races.

noname4me

Hi,
1) Looks like the engine had a flat top intake manifold for the dyno pull? (I don't see that in your parts list.)

2) What would be the impact to HP staying with the OEM cams? The cost of the aftermarket cams is a significant % of the total cost for a BP6D build. This looks like a place to decrease the overall build cost upfront, but fairly easy to add the cams at a later date.

Thank you

my97miata

According to the professionals, using the VICS(US 99-00 and MSM intake manifold) is suppose to increase the midrange torque but takes away from the top end horsepower. The 99-00 intake manifold would probably be better for an autocross and a street car than a car that is being used on a race track.

emilio700

iTrader: (3)

Square top, yes. Cams might be worth 12whp. We have never done a direct A/B test for that so I'm guessing based on a bunch of different data points. Our record power on stock cams was 174whp with a slightly higher compression 2.0L. That was an expensive engine though. Dialed back with a simpler build, 160whp is reasonable with a good valve job on BP6D cams with 85.5mm pistons on gas.

emilio700

iTrader: (3)

Generally, yes. If you need to detune for a power limited class then the NB1 manifold with VICS enabled is the best bet. Our best PTE motor used that manifold for the most torques.

my97miata

Sounds like the VICS manifold is money well spent, for a street car.

richyvrlimited

iTrader: (1)

In the USDM maybe

JDM and EUDM 01+ cars have neither VICS or VTCS.

newold_m

iTrader: (2)

Helping a local friend install the CNC head on his NB this weekend. Can't wait to see this bad boy in person..

triple88a

iTrader: (2)

I keep hoping for the hydraulic lifters to be come available. Like those from the koenigsegg free valves

EO2K

iTrader: (37)

I'm glad to hear I'm not the only one in the area who bought one. Is said "friend" here on MT? Maybe NCR? More hard data is always a good thing.

Related: I'm glad this thread got a bit o'cleanup, thanks mods

newold_m

iTrader: (2)

I don't think he's here even though he also has a sweet turbo NA. CNC head is going into his NB1 and not sure if his head is 4W or 6D. I've seen some posts from him on NCR but he's primarily on BAMD.