|
Great racing Sonny. Really enjoyed the video.
|
Originally Posted by emilio700
(Post 1526461)
As mentioned in the OP, we hope to be able to run Enduros with this car. That means low enough compression to stay on pump gas for the much greater fuel economy. We will still run E85 for Sprint and TT.
With an almost identical set up and a Mazda crate motor we made 125 whp a few years ago. So this output is anomalous. I feel is either a different cam spec or the intake manifold design on the NB6. We will find out If you're healthy NA6 motor is making less than 110 with the exact same setup, you need to rebuild the damn thing. |
I have not seen any documentation that indicates a compression ratio bump or Cam lift increase for the NB6. Can you share your sources?
|
Originally Posted by emilio700
(Post 1527416)
I have not seen any documentation that indicates a compression ratio bump or Cam lift increase for the NB6. Can you share your sources?
|
We don't have any B6 parts in the shop. Had to source them, the IM is inbound. Purpose of this thread is to document and share findings so, we will. Compression test indicates same CR as USDM NA6 although that's not scientific.
I started to think that maybe the used motor we bough had received a water pump or timing belt service and could have had its cams mistimed. B6's make peak around 7000. Ours made peak at 6200 which is pretty wack. Indicates mistimed cams more than a bad engine. So we're pulling the valve cover to check cam timing. While we're in there we'll measure cam lobes and see if they have part numbers. |
Thanks Emilio, looking forward to what you find!
|
I have a ton of 90-93 USDM manual B6 parts if any measurements/photos/numbers are needed from parts and such.
|
usdm b6 parts? wut.
|
Originally Posted by MiataMan00
(Post 1527511)
usdm b6 parts? wut.
|
Originally Posted by x_25
(Post 1527513)
They were originally sold in the US?
|
All the google searching I'v done has threads containing guy's saying the cam lift is higher on intake, but that's all it is: guy's saying, so at this point it's unknown, until Emilio has time to measure the lobes, or someone else who has had one apart can offer up the definite info.
|
I have a low-mileage 1.6 that I've been slowly modifying, and so I'm really curious how this engine build goes. The "we don't modify 1.6s we swap 1.8s in" line makes sense for most people, but not those of us who are unreasonably stubborn about keeping ours! So it's nice to see there are some reasons to use a 1.6 (a bit shorter for better weight dist, a bit lighter overall), and it'll be interesting to see how much you get from it. I know you'll have to tune your car to 132 HP to make the lb/hp ratio specified by the rules, but I also wonder what the not-detuned HP limit will be on this engine when it's complete. And also how you'll modify the tune for endurance racing (if I'm reading into that correctly), is that just a change in redline, or timing or what?
It's super cool that you started with a NB, not many people could or would do it that way. Which makes me wonder if you had started with a 90-93 body, would you have used an airdam or still gone with BTM bodywork? Or maybe that would be track dependent? |
Miata Engine History and Interchangability Guide This guy seems to know quite a bit about the engine's development over the years. He states that the JDM 1.6 shares the same cam specs as the US 1.6, but advances the intake timing a few degrees, in addition to the solid lifters. Cam # is: BP5A12420. Compression ratio is the same as well.
|
Checked cam timing, lift on cams. Different P/N's than USDM, Difficult to get a solid answer from interweb on just which version we have. Starting to think that we have the "90bhp" version sold from 94 on outside of the US. Wiki page states that the NB6 was bumped to 110bhp from 99 on.
JDM NB6 cams in it have .5mm les intake but .35mm more exhaust lift than USDM manual NA6 cams. Small change. Whichever cams we have, the Kelfords, 9mm In & Ex are going in along with adjustable cam gears. We're so far down on power that just swapping OEM cams isn't going to get us there. Glad I ordered the Kelfords 4 months ago (just arrived). Was hoping we would make the power with a junkyard JDM motor. Didn't. So far at least, it appears starting with a freshly rebuilt NA6 motor is probably a better choice. While you are rebuilding, shave block to bring CR to about 10.0:1 while retaining squish. If you have budget leftover, deshroud and bowl blend. That should, base don our past experience, get you to about 135whp on corn. Meanwhile, we'll swap cams and start A/B testing intake manifolds. Also ordered a JR header (4:2:1) to A/B against the RB (4:1). For science. |
NB6 cam lobe measurement and NA6/NB6 intake manifold comparisons
We measured the lobes and checked the casting marks on the camshaft today.
NB6 intake (B6KP): 7.25 mm NB6 exhaust (B6MC): 8.25 mm For reference, USDM NA6 intake: 7.86 mm USDM NA6 exhaust: 7.9 mm Checked the timing belt for misalignment, but the timing looks good. USDM NA6 manifold and auto trans TB showed up last week and visually compared it to the NB6 manifold. Looks like the TB on the NA6 manifold mounts further back than the NB6. Also noted is the downward angle the NA6 manifold has compared to the more parallel to the ground angle shown with the NB6. https://cimg4.ibsrv.net/gimg/www.mia...e8c20db7f8.jpg https://cimg6.ibsrv.net/gimg/www.mia...f8012e340c.jpg https://cimg7.ibsrv.net/gimg/www.mia...424373f762.jpg |
WSIR Race 2 footage (3/17/19)
Race 2 is up. The lack of power is annoying, but made the racing epic. However, it is not as annoying as the racecraft I had to deal with starting at 17:00. After all of that while trying to keep calm, the race for P3 ended in a dead heat with timing showing a tie to the 1/1000th second, but I lose the tiebreaker.
|
Races like this get me fantasizing about fender mounted machine guns! Nice job!
|
Not sure what the deal is over there, but here in Australia you are allowed to move the car once to cover your line, but you cannot then swerve back across to block another line. The other driver was a bit of a poor sport in my view, there were times I counted him swerving up to 3 times to block you - that's not cricket sir!
|
Originally Posted by ninerwfo
(Post 1528554)
Not sure what the deal is over there, but here in Australia you are allowed to move the car once to cover your line, but you cannot then swerve back across to block another line. The other driver was a bit of a poor sport in my view, there were times I counted him swerving up to 3 times to block you - that's not cricket sir!
Said driver has been contacted nad "talked to" by racing organization after chief steward saw the video. I believe the race directors comment to Sonny after viewing the video was.. well, lets just say the RD might not have been so patient had he been in Sonny's seat. |
When you take "Rubbin' is racin' " a little too literally.
For real though, props to you Sonny for being so patient. Way to hold your cool. |
cant wait to get a closer look at the usefullness of a nb6 intake vs usdm.. maybee some dyno numbers. volume numbers? I always felt the 1.6 intake did not have enough plenum for 7K RPM
|
Originally Posted by emilio700
(Post 1528555)
Same rules here. One move is pretty much the norm across the globe. That driver, on his provisional (learners permit) license no less, had the audacity to tell Sonny (pro coach, 3x national champ, multi lap record holder) "That's what racing is, get used to it" or some such malarkey.
Said driver has been contacted nad "talked to" by racing organization after chief steward saw the video. I believe the race directors comment to Sonny after viewing the video was.. well, lets just say the RD might not have been so patient had he been in Sonny's seat. |
Originally Posted by VagaXt
(Post 1528153)
We measured the lobes and checked the casting marks on the camshaft today.
NB6 intake (B6KP): 7.25 mm NB6 exhaust (B6MC): 8.25 mm For reference, USDM NA6 intake: 7.86 mm USDM NA6 exhaust: 7.9 mm Checked the timing belt for misalignment, but the timing looks good. USDM NA6 manifold and auto trans TB showed up last week and visually compared it to the NB6 manifold. Looks like the TB on the NA6 manifold mounts further back than the NB6. Also noted is the downward angle the NA6 manifold has compared to the more parallel to the ground angle shown with the NB6. Can you confirm if the TB mounting pattern for the NB6 manifold is the same as the 1.8? Being able to add a Junk2 TB to an NA6 might be nice. |
Confirmed; it is the same. OEM NB6 and NB8 TB assemblies are identical.
|
Originally Posted by HarryB
(Post 1528615)
Confirmed; it is the same. OEM NB6 and NB8 TB assemblies are identical.
|
Yup. Those of you 1.6 guys wanting a Junk2 throttle body, get you an NB6 intake manifold. Also gets rid of what i-don't-even-know-what-the-hell-that-crap-is IAC system.
|
Originally Posted by concealer404
(Post 1528626)
Yup. Those of you 1.6 guys wanting a Junk2 throttle body, get you an NB6 intake manifold. Also gets rid of what i-don't-even-know-what-the-hell-that-crap-is IAC system.
|
Originally Posted by emilio700
(Post 1528151)
So far at least, it appears starting with a freshly rebuilt NA6 motor is probably a better choice. While you are rebuilding, shave block to bring CR to about 10.0:1 while retaining squish. If you have budget leftover, deshroud and bowl blend. That should, base don our past experience, get you to about 135whp on corn. Meanwhile, we'll swap cams and start A/B testing intake manifolds. Also ordered a JR header (4:2:1) to A/B against the RB (4:1). For science. https://cimg0.ibsrv.net/gimg/www.mia...ad90b5e2de.jpg And for a little future reference if it may help someone, same motor with port matched T3 manifold and black top 4age ITB'S , 100mm trumpets with ITG filter installed. https://cimg7.ibsrv.net/gimg/www.mia...d999a87b28.jpg No gains were found with cam timing adjustments as well on either setup. |
Originally Posted by gt5759
(Post 1528675)
Pretty accurate assessment. Here is a fresh NA6, .050 off the head, stock valves, stock 1993 cams, super singles, RB header, 45* intake tube, haltech, E85.
And for a little future reference if it may help someone, same motor with port matched T3 manifold and black top 4age ITB'S , 100mm trumpets with ITG filter installed. No gains were found with cam timing adjustments as well on either setup. Emilio; any reason you specify shaving block vs head? Don't the stock pistons protrude ~.010" at TDC with a stock deck height? |
Whatever method preserves squish. I'm not too familiar with the B6. With BP's, it's easier to deck it. Less machine work to preserve squish and deshroud areas that way.
In either case, stick below 10.3:1 or so for CA91, 10.4:1 for 93. If only E85, then 11.0:1 works nicely. B6 makes a good enduro motor as it's pretty easy to get it to run the 2hr max driver stint length for most sanctioning bodies. But it'll only do that on gas, thus the conservative CR for enduro. We have not pulled the head and hope not to need to. |
Adapting NB Throttle Body to NA6 USDM Intake Manifold
In the quest for more power, we are going to try using a NA6 USDM intake manifold. To avoid unnecessary splicing of wires on Miller's engine harness, we are going to adapt the NB throttle body to the NA6 intake manifold. Here some mock up and progress photos.
Top two holes of the TB and IM line up perfectly, but some air channels on the NB throttle body look like they will cause vacuum leaks. https://cimg7.ibsrv.net/gimg/www.mia...a8f8df7a50.jpg https://cimg8.ibsrv.net/gimg/www.mia...d343de3e94.jpg The bottom two holes do not line up with each other. https://cimg9.ibsrv.net/gimg/www.mia...f346f47872.jpg Not only bore hole sizes are different between the NB TB and the NA6 IM, the centers are offset from each other. https://cimg1.ibsrv.net/gimg/www.mia...cdea38bc6e.jpg John getting to work on porting. https://cimg3.ibsrv.net/gimg/www.mia...22ca87ef6a.jpg Beautiful smoothness. https://cimg5.ibsrv.net/gimg/www.mia...70c0dfe006.jpg https://cimg8.ibsrv.net/gimg/www.mia...97cb1f1855.jpg There's a problem trying to seal up potential vacuum leaks, but another gasket can fix this. https://cimg9.ibsrv.net/gimg/www.mia...eb73c0e5b0.jpg There's the second gasket mounted backwards on top of the first one. https://cimg0.ibsrv.net/gimg/www.mia...37759e4a8e.jpg Note that we had to slot one of the holes for the NB TB to mate to the NA6 IM. A nut and bolt will work here to clamp everything down. https://cimg4.ibsrv.net/gimg/www.mia...d670284b8f.jpg NB TB is mounted and mocked up! https://cimg6.ibsrv.net/gimg/www.mia...143eb0c1c1.jpg https://cimg1.ibsrv.net/gimg/www.mia...498dac2660.jpg https://cimg3.ibsrv.net/gimg/www.mia...189cfa5c15.jpg https://cimg5.ibsrv.net/gimg/www.mia...a5a6dd6363.jpg Mmm.. ported! https://cimg8.ibsrv.net/gimg/www.mia...5d7ae50e54.jpg |
NA6 Intake Manifold Install to NB6 Block
Modified NA6 manifold ready for install. We are crossing fingers that it may make more power.
https://cimg6.ibsrv.net/gimg/www.mia...16051d8b17.jpg It seems the JDM B6 has two water ports that connect with the intake manifold. https://cimg6.ibsrv.net/gimg/www.mia...2ac00ba3ce.jpg Though the gasket has holes for both water ports, both USDM NA6 and JDM NB6 intake manifolds have the trapezoidal water port blocked. Both manifolds have the circular water port to allow coolant to flow to both the NA6 and NB throttle bodies. https://cimg3.ibsrv.net/gimg/www.mia...774f394492.jpg https://cimg5.ibsrv.net/gimg/www.mia...17090c6dc4.jpg Backsides of the JDM NB6 (left) and the USDM NA6 (right) intake manifolds. It is interesting that the runners on the NB6 IM is more squared off than the smoother, wider radius of the NA6 IM's runners. Maybe the smoother, wider radius means more air flow and more power? We will find out on the dyno soon. https://cimg9.ibsrv.net/gimg/www.mia...1de0600ac1.jpg Side views of both JDM NB6 (left) and USDM NA6 (right) IMs with NB throttle bodies mocked up. Note the longer and straighter approach to the plenum from the TB for the USDM NA6 IM. https://cimg2.ibsrv.net/gimg/www.mia...a739dbf639.jpg Close up of the USDM NA6 IM. https://cimg4.ibsrv.net/gimg/www.mia...774734a31c.jpg Close up of the JDM NB6 IM. https://cimg6.ibsrv.net/gimg/www.mia...4c4035b5dc.jpg Handmade idle air control block off plate for the USDM NA6 manifold. https://cimg7.ibsrv.net/gimg/www.mia...e78946233e.jpg 59 mm inner diameter for the TB opening of the JDM NB6 IM. https://cimg8.ibsrv.net/gimg/www.mia...5e5600de0f.jpg 55.5 mm inner diameter for the TB opening of the USDM NA6 IM. https://cimg0.ibsrv.net/gimg/www.mia...2d70874509.jpg Verified: NA6 and NB6 IM gaskets are the same. https://cimg3.ibsrv.net/gimg/www.mia...15bffda468.jpg USDM NA6 dressed and ready for install. 1.6L fuel rails are interchangeable between manifolds. Also, 3 vacuum line bungs had to be capped. https://cimg4.ibsrv.net/gimg/www.mia...d16773c72f.jpg Swapping TB cables because of the different TB bracket mounting locations between the NA6 and NB6 IMs. https://cimg6.ibsrv.net/gimg/www.mia...f198f493e5.jpg New TB angle means new intake pipe routing. https://cimg9.ibsrv.net/gimg/www.mia...1846f2f42e.jpg New intake routing completed. https://cimg0.ibsrv.net/gimg/www.mia...b74eb23bdc.jpg |
Shorter runner length should tune the RPM range slightly higher, possibly at the cost of low-mid range.
|
Mazda marketing literature from NB6 era states that it was tuned for more torque. The B6 was already an archaic design in 2001. Tough to meet emission standards. No real reason to tune it for power when anyone that could afford power would just by the BP version.
Of note were the advertised peak power rpm of the 90bhp NB6 at 6200rpm, same we saw with ours in stock form. Swapped cams and still 6200rpm peak power. That is all intake manifold influence I think. For reference, a stock NA6 makes peak power closer to 7000rpm. The two key items of the NB6 responsible for it's meager output were cams and intake manifold. Changed both, Dyno this afternoon. We'll see. |
Can't wait for the update man.
|
Interested in your treatment of the throttle butterfly screws. Care to elaborate on the thinking there?
My collection of busted shafts and lost screws would like to know ... |
Originally Posted by Gee Emm
(Post 1531383)
Interested in your treatment of the throttle butterfly screws. Care to elaborate on the thinking there?
My collection of busted shafts and lost screws would like to know ... |
Oh well
No joy. Made a few more whp with the NA6 IM and RB header but still way below what we need to be competitive in ST6. Motor, at 6% leakdown is just too tired.
Of note is how much less the RB fell off after the power peak. JR vs RB header. In the past, with much bigger cams we saw the 4:2:1 JR worked better than the RB. As the cams get milder, the RB seems to have more total area. https://cimg7.ibsrv.net/gimg/www.mia...e6073bd994.jpg NA6 intake manifold vs NB6. We expected to see the power peak more than the 150rpm we see here. Also expected another 8-10whp, not 2whp :p. https://cimg1.ibsrv.net/gimg/www.mia...0c7b91120f.jpg I made a lot of pulls doing sweeps on injection timing, ignition timing and AFR on each hardware combo. So each was optimized. Based on the 125whp we made with a Mazda NA6 crate engine, E85 and RB header, I think we would hit 135whp or so with the Kelford 203B cams. Sonny will decide if he wants to put a BP back in or not. |
Man.... y'all sure that dyno isn't reading low here recently?
|
Nuts :(
|
Originally Posted by Arca_ex
(Post 1531396)
If the screw head snaps off it will be captured instead of getting into one of the cylinders and destroying your engine.
I was actually more interested in the material added, what it was and what if any steps were taken to ensure that none of that came off. (* although the last time it happened, the screw got caught in between the closing valve and the seat, allowing the SUB to float sideways and jam the valve slightly open. Had to pull the head off, touch up the seat(s), and all good - not what I call destroying the engine. That was when the Skunk TB was installed. Another Skunk TB on my current car.) |
Emilio, it may be a tired engine, but if you have another TB I'd suggest a TB swap and another dyno run, to ensure that the additional material on the TB butterfly is not disturbing the airflow. The top looks OK (as far as can be told with photos), the bottom doesn't look as smooth.
|
We did not use that throttle body. It was only used for mock up. We used the TB that came with the NB6 engine.
For the epoxy to work you have to get the butterfly and shaft clean... cleaner than is possible with ordinary methods. We were going to experiment with ultrasonic cleaning and various epoxies, and then curing them in an oven. That project got sidelined years ago. Too many projects and not enough time for me to do them. |
Originally Posted by Satisaii
(Post 1531668)
We did not use that throttle body..
Agree about the surface prep! I'd also be looking at anything mechanical that might help the epoxy adhere, maybe even a couple of extra holes in the plate to help keep the epoxy on board. Sounds like it's academic now anyway. Skunk is an easy button fix, rules permitting, but may be too big for the 1.6? |
Originally Posted by Gee Emm
(Post 1531658)
None of the four(?) that I lost damaged* my (atmo) engine, but a turbine wheel would be another matter entirely.
http://www.codrus.com/miata/teardown/head4.small.jpg --Ian |
Originally Posted by codrus
(Post 1531671)
They do a number on turbines, but pistons & heads aren't immune.
--Ian |
NASA ST6 Power to Weight Optimization
Since it would cost more money to rebuild the B6, it's time to swap back Miller's original SuperMiata S2 motor (BP5A) for ease and convenience for achieving our power-to-weight goals. In theory, the B6 engine can make the power target requirements, but we need a fresher motor. Maybe one day a fully-optimized B6-equipped ST6 Miata will be verified on track.
https://cimg4.ibsrv.net/gimg/www.mia...e2c0b2628f.jpg Here's a comparison for Miller's current tune for ST6 on a BP5A motor vs. the best B6 configuration before the swap. Our target is 133whp average HP for 2474 lbs minimum competition weight, so Miller also had to gain weight to fit the adjusted power-to-weight (P:W) ratio. Also, we had to further optimize for less P:W penalties for swapping extended lower ball joints for front control arm offset bushings(from -0.2 to 0 P:W penalty) and gain a weight class from 2250 lbs to 2400 lbs (going from -0.4 to -0.3 P:W penalty). A bonus for being heavier (over 2400 lbs) is that now we get to upgrade to better contact patch by switching from 15x8 to 15x9 on 205 Hoosier R7s. https://cimg0.ibsrv.net/gimg/www.mia...a52f4282be.jpg https://cimg3.ibsrv.net/gimg/www.mia...bd8fd599d0.jpg We had to take two days for dyno sessions to diagnose a fueling issue. A dying fuel pump was culprit. We replaced the fuel sock and the in-tank fuel pressure regulator as a precaution. Good to say, we have power for full ST6 optimization. https://cimg7.ibsrv.net/gimg/www.mia...7aad3a8fa8.jpg https://cimg6.ibsrv.net/gimg/www.mia...cc29be65d4.jpg https://cimg5.ibsrv.net/gimg/www.mia...8ba0d3e0d6.jpg While I'm in there, changing out XIDA Race front springs from 800 lb/in. to 900 lb/in. for more handling balance fine tuning. https://cimg7.ibsrv.net/gimg/www.mia...c740b1f730.jpg https://cimg0.ibsrv.net/gimg/www.mia...1037471462.jpg https://cimg2.ibsrv.net/gimg/www.mia...7d325f3b16.jpg |
Eager to see what a fully optimized NA/NB can do in ST6. I think the 944's still look better on paper but hoping some Sonnymod and Supermiata tuning expertise will make up the difference.
|
Never underestimate the #sonnymod.
Plus, I turned wrenches on the car. Now it's guaranteed to win :ugh2: |
| All times are GMT -4. The time now is 07:05 PM. |
© 2024 MH Sub I, LLC dba Internet Brands