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Garage Quinn Motors - GQM
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Discussion Starter #1 (Edited)
Some of you may remember my thread from a while back when I was able to extract 172 whp out of a stock block BP.

http://clubroadster.net/vb_forum/59-irtb-individual-runner-throttle-bodies/81194-my-172whp-n-engine-stock-bottom-end-no-porting.html

IMG_20150307_184451 by Maximus5891, on Flickr

Here is the next round of modifications I performed that brought that figure up to 185 whp.

The last setup consisted of a stock 02 Block, a BP4W head shaved to .060” (stock ports), 264’ Maruha Cams, Toda Cam Gears, Supertech Valvetrain, Mazdaspeed SUBs, TWM 45mm ITB’s, and a Maruha VP Race Header. The key was making this setup easily reproducible. If the block fails, you can go buy another stock block and be back up and running quickly. If you needed a new head, you could buy one and the only machine work needed would be a 135.00 shave. No rotating assembly work, no clearancing (other than cold lash), no balancing, no porting, etc.
The rev limit was raised for this setup to 7800 RPM. Rod strength becomes an issue past this point. This setup held up fine for me with heavy street romping and track time.

There was always the question of if there was still power left on the table. Factors like the size of the ITBs, the Venturi in the Maruha manifold, always left the question of a possible bottle necks. So after finding a slow leak at the oil pan (which I never changed from the donor 42k mile block I used) I pulled the engine and went forward with seeing just how far I could push this engine on the stock block.

Videos on this setup:

Overview:

ITB Filter Options:

Driving videos:



***WARNING PLEASE READ*** In regards to this latest build, I DO NOT RECOMMEND pushing a BP this far and is certainly not for the faint of heart. If you want budget BP power, there is nothing wrong with my .060” shave setup I have done above. That combined with mild cams and decent breather mods will provide a fun, reasonably priced, reliable power and an easily reproducible setup. If you want big N/A power (170+ whp), then go for a Honda K Series Swap. The motors are superior in every way possible compared to the BP. If the option was available years ago when I started this build, I would have taken that road in a heartbeat. The K-Series engines can do 200+ whp without bottom end work all day long and do it reliably for a while. A built to snot BP will just barely be touching those power levels and will certainly not last nearly as long. Also, let it be known that the 1.6 L B6 should not be considered for all motor power. Forced induction is fine (see my turbocharged 254 whp stock internal 91 Miata) however for all motor power, just save your money and frustration and go right for a 99+ engine.
So for my latest build, here is what changed over the last setup. The head is now ported. All of the flash was cleaned up and smoothed out. Just by doing this you increase the size of the port area. CNC porting and a proper port design will take you a little further, but most of the gain comes from smoothing everything out. The ITB’s were bored from 45mm to 50mm and the head side of the manifold port matched to the now bigger intake ports. The 60mm to 50mm Venturi in the header has been removed to prevent bottle necking the increased flow. The head shaved another .040” for a total of .100” head shave. By Solo Miata’s calculations, you gain .25 compression for every .010” you shave, this would mean that at .060” shave the 10:1 BP05 block becomes 11.5:1, at .100” it gets bumped up to 12.5:1. Bear in mind that bigger cams have overlap and bleed off compression. When I compression tested the block with a stock head it was ~200 psi per cylinder, after .060” shave and 264’ cams it was 205-210 psi per cylinder, now with .100” shave and 264’ cams it is 230-240 psi per cylinder. To top things off, I added a Boundary Engineering oil pump with billet gears and a 949 Racing Super Miata Harmonic Balancer.

Problem areas:
When you shave .060” off of the head, the stock timing belt tensioner can account for the slack in the belt. The engine does become interference. 10mm lift cams are interference valve to valve wise. After .060” however, the stock tensioner can no longer properly tension the gain in slack and the 10mm lift cams will kiss the crown of the valve reliefs on the piston. I saw this when I puttied the engine up again with the .060” shaved head and no head gasket, which is .020”, so this would simulate an .080” shave. To solve the tensioner issue, I used a puller to remove the bracket from a second tensioner pulley and put this in place of the idler pulley. This allows for tensioning at both pulleys and provides enough tensioning to accommodate the .100” shave. As far as the valve to piston clearance issues, I made a template to dremel the reliefs bigger the same amount across each piston. I did not disassemble the block to do this. It is a very small amount of material that is removed from each piston. With these modifications I was able to run this setup. There is still another ~.020 to .040” of material left on the head, but I don’t think it is worth shaving it that far.

Results:
So this new setup achieved another 13 whp and 5 lb/ft of torque for a total of 185 whp and 134 lb/ft. The gain is from 6000 RPM to 7800 RPM rev limit. There was a slight loss in power below 4000 RPM, which is most likely the result of removing the venturi from the header and possibly opening everything else. I’d also like to not that at 11.5:1 compression and 93 octane I could advance timing up top past the point where there was no gain in power and there was no detonation issues. Now with 12.5:1 and 93 octane, I did have to retard timing a little, but am still running more timing advance than stock. With race gas or e85 this engine would make in the 190 whp range. Also note that conditions in the dyno compared to my last setup were 20’F hotter. I was running out of time from monkeying with the gears, so for the final pull I only let the engine cool down for about 6 minutes. This resulted in an additional 2 whp just by letting it cool a little. With cooler air temps and less heat soak it would probably make closer to 190 whp. So how fast is it in the real world? At 172 whp, my friend’s AP2 S2000 with intake duct, high flow cat, and 70 mm exhaust would leave me right away from a 2nd gear pull. Now I pull ahead of him right away and stay there up to about 100 mph and then the aero drag of the Miata and just lack of overall horsepower starts to make the car fall behind. However, it is definitely an overall faster car in the real world now. I'll end it with this though. I think this is the max I would ever do to engine. I plan on keeping this setup as long as it will last. The idea of eventually switching to a K-Series still lingers in the back of my mind though.

:icon_cheers:

quinn itb 50mm by Maximus5891, on Flickr

All 3 all motor setups this engine has had:

quinn itb 50mm vs by Maximus5891, on Flickr

Conditions during each dyno session:

quinn itb 50mm vs2 by Maximus5891, on Flickr

Engine:

2002 Block 10:1 compression
1999 BP4W head, ported and shaved .100”
Maruha's 264’ / 264’ 10mm Lift Camshafts
Toda Adjustable Cam Gears
Supertech Single Valve Springs
Supertech Titanium Retainers
Mazdaspeed SUBS
New OEM Valve Seals
OEM Head Gasket .020”
TWM 50mm Individual Throttle Bodies
36 lb Fuel Injectors
ITG Sausage filter and backing plate
Hondata Intake Manifold Gasket
Adaptronics Standalone ECU
Maruha VP Race Header without Venturi
Racing Beat Resonated Race Pipe 2.375"
Jet's Integral Kobe Muffler 2.375"
Garage Star Alternator and Waterpump Pulleys
949 Racing Super Miata Crank Pulley
Boundary Engineering Billet Oil Pump
6.2 lb Spec Billet Pressure Plate
7.1 lb Fidanza Flywheel
1.3 lb Clutchnet Unsprung Street Disk
Golden Eagle Vacuum Manifold
Chikara Motorsports Oil Catch Can
Koyo 52mm Radiator
Koyo 1.3 Bar Radiator Cap
Mishimoto Slim Fan
Samco Radiator Hoses
Flyin Miata Oil Cooler Kit
Beatrush Radiator Cooling Panel


Videos:

Engine Overview:

First start:

Dyno:


IMG_20150308_034330 by Maximus5891, on Flickr

IMG_20150326_233644 by Maximus5891, on Flickr

IMG_20150308_012206 by Maximus5891, on Flickr

IMG_20150711_175835 by Maximus5891, on Flickr

IMG_20150831_180918 by Maximus5891, on Flickr

IMG_20150912_230400 by Maximus5891, on Flickr

IMG_20151005_122001 by Maximus5891, on Flickr

IMG_20151003_214035 by Maximus5891, on Flickr

IMG_20150802_014943 by Maximus5891, on Flickr
IMG_20150808_230434 by Maximus5891, on Flickr

IMG_20151019_213912 by Maximus5891, on Flickr

IMG_20151016_202526 by Maximus5891, on Flickr


IMG_20151005_234559 by Maximus5891, on Flickr

IMG_20151010_140729 by Maximus5891, on Flickr

IMG_20151011_000034 by Maximus5891, on Flickr
 

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Garage Quinn Motors - GQM
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Discussion Starter #2 (Edited)

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I enjoy all your videos, and build threads. Congrats for the great numbers! I have a question though. The crowns of the pistons aren't supposed to have had special heat treatment (sorry, english is not my first language, I don't know how to translate technical stuff)? By removing material, don't they get weaker at these spots?

Στάλθηκε από το GT-N5100 μου χρησιμοποιώντας Tapatalk
 

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Garage Quinn Motors - GQM
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Discussion Starter #6
I enjoy all your videos, and build threads. Congrats for the great numbers! I have a question though. The crowns of the pistons aren't supposed to have had special heat treatment (sorry, english is not my first language, I don't know how to translate technical stuff)? By removing material, don't they get weaker at these spots?

Στάλθηκε από το GT-N5100 μου χρησιμοποιώντας Tapatalk
I don't think the factory pistons are coated.

Where does the oil catch can breather tube go? And why didn't you just put a small KN filter on?
It vents out of the center of the belly pan. I had a filter but it would spray oil vapor residue all around it.
 

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Every full-on NA build I've ever read (non-Miata) has always ended with the same conclusion: it's all in the head. Going by your description of what's been done to your cylinder head, basically a mild PnP on stock size valves, I think there's still a good amount of power that's been left on the table. I'd wager that 200whp is perfectly achievable, if not more.

However: the money you'd spend on properly developing the cylinder head would likely be much better spent on a K-swap that would already be making those numbers stock, pretty much, as you yourself have said.
 

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Firstly both your threads are extremely informative and this is fantastic information all round.

I only had one question, do you know what the dip at 5500rpm is? Is it trumpet length or cam timing?
 

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Garage Quinn Motors - GQM
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Discussion Starter #10
Firstly both your threads are extremely informative and this is fantastic information all round.

I only had one question, do you know what the dip at 5500rpm is? Is it trumpet length or cam timing?
Wondering about this as well.

The cams. The engine didn't have the dip before with the cams. I have seen others that have cams with the same thing. However, it could be the combination of the cams, header and ITBs.
 

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Hey Quinn, I saw this and thought you might find it useful whenever you start building the bottom end. It's an interesting article on how Formula Atlantic 4AGE engines are built to have 200whp. My favorite technique here that I've never heard of is polishing and shotpeening the interior block to speed up oil return and prevent casing from breaking off and entering the oil. http://www.motoiq.com/MagazineArticles/ID/1356/Extreme-Engine-Tech-Technosquares-Monster-Naturally-Aspirated-Toyota-4AG.aspx
 

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Very awesome!
 

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The engine looks magnificent... makes me want to pretty mine up a bit!

I have a BP05 head that's been decked a bit more than yours. To fix the belt tension issue I run a KIA idler that is 2mm larger diameter than the Miata one. I can't remember what model it's off though. The larger pulley tightens the belt up a fair bit, however I have still had the belt skip a tooth once on a big backfire whilst cranking.
 

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Garage Quinn Motors - GQM
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Discussion Starter #14
The engine looks magnificent... makes me want to pretty mine up a bit!

I have a BP05 head that's been decked a bit more than yours. To fix the belt tension issue I run a KIA idler that is 2mm larger diameter than the Miata one. I can't remember what model it's off though. The larger pulley tightens the belt up a fair bit, however I have still had the belt skip a tooth once on a big backfire whilst cranking.
How much did you shave and on what bottom end? I'd be interested to hear more about your build.
 

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I don't want to clutter up your thread but basically I'm running Crowler rods, Wiseco 84mm 10.5:1 pistons, external oil pressure valve, no squirters. I rev up to 8500 which is where my power band is so a stock bottom end wouldn't hold up for long.

Compression is somewhere between 12-13:1. I need to measure the head to know how much was shaved off but I think it was 2mm which is 80 thou. I need big reliefs in the piston crowns due to high lift cams, oversized valves and cut head. All up I'm only about 3-5 degrees from interference on both valves.
 

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Garage Quinn Motors - GQM
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Discussion Starter #17
I don't want to clutter up your thread but basically I'm running Crowler rods, Wiseco 84mm 10.5:1 pistons, external oil pressure valve, no squirters. I rev up to 8500 which is where my power band is so a stock bottom end wouldn't hold up for long.

Compression is somewhere between 12-13:1. I need to measure the head to know how much was shaved off but I think it was 2mm which is 80 thou. I need big reliefs in the piston crowns due to high lift cams, oversized valves and cut head. All up I'm only about 3-5 degrees from interference on both valves.
Ah good stuff. I shaved .100" off of this head, which is 2.54mm. The factory valve reliefs aren't very big so I had to make them bigger to make the setup work :)

I like what you did with the Honda intake manifold. That is a great route to go to free up flow to the head without using ITBs.

Yes, my 264' duration 10mm lift cams are also interference valve to valve wise.

What are the specs on your cams?
 

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My cams are a custom grind at around 310 duration. They are so wild I get lots of people asking if I'm running a rotary! Idle is very lumpy and really the engine doesn't work until around 4000 rpm.

I would have liked to try ITBs but the Honda manifold popped up cheap on eBay and I couldn't resist trying it. It ended up working far better than expected.
 
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