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My 172whp N/A Engine. Stock bottom end. No Porting.

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93K views 149 replies 63 participants last post by  ManiacLachy  
#1 ·
I am posting this in the ITB section because I know my build thread is not seen as much throughout the board. I hope this will be of some use for people trying to make N/A power without getting into expensive and risky bottom end work.

The head on my engine is not ported at all, just shaved .060". Supposed to be around 11.5:1 compression now, but I am not sure if it was actually raised that much. The key here is making this setup easily reproducible. If the block fails, I can go buy another stock block and be up and running quick. If I needed a new head, I can 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.

Engine:

2002 Block 10:1 compression
Cams are 264 / 264 10mm Lift Maruha's
Supertech Single Valve Springs
Supertech Titanium Retainers
Mazdaspeed SUBS
Toda Adjustable Cam Gears
New OEM Valve Seals
OEM Head Gasket
TWM 45mm Individual Throttle Bodies
36 lb Fuel Injectors
ITG Sausage filter and backing plate
Hondata Intake Manifold Gasket
Adaptronics Standalone ECU
Maruha VP Race Header
Racing Beat Resonated Race Pipe 2.375"
Jet's Integral Kobe Muffler 2.375"
Garage Star Alternator and Waterpump Pulleys
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

This stock 02 block at 10:1 compression, tested at 200-205 psi in each cylinder with the stock cams in previously. With the new cams creating more overlap and the head shave at .060" supposedly 11.5:1 compression, it tests at 205-210 psi in each cylinder. So with stock cams in the head creating less overlap it would most likely test much higher compression on the gauge. Honda's F20c at 11:1 compression on the non-VTEC lobes compression tests around 230-240 psi depending on the gauge.

With a .060" shave and 10:1 factory pistons, there is still a good 1-1.5mm of clearance in the reliefs. My friend/tuner was telling me to shave .080", but I was scared because the highest I was told I can go was .030", and I asked a lot of the big name Miata guys this too. I should have done .080". If the head ever comes off, I am going to shave it again to .080".

The results of all of this? Here are before and after comparisons of both the corrected dyno numbers and the uncorrected (what car was actually making at that very point in time). We fiddled with the cam gears on the street and on the dyno as well. These engines are not very sensitive to timing changes. Changing the cam and ignition timing yielded very little results. We advanced and retarded both the intake and exhaust cam quite a bit, but nothing significant changed. When we originally baselined the car it made 168 whp and 124 ft/lb's. We were however able to pick up a good chunk of mid-range power and settled with both the intake cam advanced about 6-7 degrees and the exhaust cam advanced about 3-4 degrees. We spent some time trying to get that funky dip out at 2600 rpm, but were only able to flatten it a little. We think it is just the nature of the cams and maybe the combination of them, the ITB's, and the header as well.

So there you have it. The idea behind this build was to avoid getting into costly bottom end work or head work and making the setup easily reproducible. Literally the only machine work required if the motor were to fail worst case would be shaving another head for 135.00.

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#3 ·
Awesome stuff man! What's the rev limit set at? I'd assume those cams like to rev a bit higher than oem red line. Your MS sub lifters should be good for it IMO.
Edit* looking at the dyno graph it seems the power plateau's at around 7800 rpm.. Not bad lol

Makes me wonder how much my engine would safely make using the ex-in cam and stock exhaust cam with a ported head and 84.5mm pistons.. I'll be glad if I can achieve 165 whp..

Enjoy the car, I bet it's sweet as **** to drive.
 
S
#10 · (Edited)
Got a few questions I guess somepeople might be thinking about.
1. What kind of gas are you using?
2. How are your rods? I've heard substained 7500+rpm is bad for them. I would probs run some cheap $300 rods, just swap in your old engines bearing, right? Should keep the same clearances, as the only thing difference would be the rods contacting the outer bearing surface, but then they are made to take stock bearings. Well, mean while your "replacement 01+" engine is in your backyard might as well work on it. And..balancing! I'm sure while your at the machine shop, this shouldnt break the bank. The question is, do you take the crank and flywheel to get balanced as well? Maybe pull the pistons out as well, a piston ring compressor shouldn't cost that much and it shouldn't be that difficult to take them out and put in for the newb.
3. For those that don't need $$$ lifters/specialty cams if you stay below 7800, or so I've read. Just adding to the thread.
4. Besides the awesome header, whatelse are you running as exhaust. Would using a 2.25 FM midpipe help?
4b.I've read that the stock 99 muffler flows well up to 6psi of boost, so I would think it would do fine for a moderate NA build or whatever 6psi equals to power-wise. I'm sure you used a different one due to weight and not flow. Correct?
5. What gains do you expect to see going from .060 to .080th of a shave?
5b. I've been told after a certain shave the top rubber of the waterpump doesn't fit and timing the engine/belt is more difficult as thing don't line up as well.
 
#17 ·
That would defeat the purpose of what I am doing here. I don't think you understand the repercussions of taking apart the rotating assembly. Factory stuff is assembled in the right conditions and clearanced properly. If you are going to go into the bottom end, you need to do it all and do it right. It's not going to be cheap and it certainly doesn't mean extra reliability. With timing tuned correctly, 7800 rpm is fine.

Exhaust is full 2.375" as noted above.

If I thew a stock exhaust on this setup I would certainly lose power. Why bottle neck all the high dollar parts when a matched flowing muffler costs less then 300.00?

You are throwing out a lot of random **** here, built motors, stock exhausts? You need to have a goal and build according to that goal. My goal was to pull as much horsepower out of my motor, while making the setup easily reproducible. Machine work, headwork, is not as easily reproduced and everytime you have a failure it costs that much more and takes that much longer to get your setup back up in running. I can easily have this car back up in running in a matter of hours by swapping in another stock 01-05 block. You can't do that with a built block. Replacement head? 1 day turn around for another shave. Only thing that will take time is waiting for lash caps to come in if I have to order more. Turn around for a ported head? Definitely longer. Will it match how the head was ported previously? Probably not. Will another built block and ported head cost a lot of money? You bet. Will the tune be the same? Probably not.

When I checked clearance after the shave, I did it with no head gasket. OEM gasket is .020, so it was actually simulating a .080 shave and it was fine.


miata2fast said:
I would like to hear the OP, but would like to comment on some of the items.

I built a pretty healthy motor, and because I was on a budget, I stuck with the stock rods. I turned my motor to 8000 on the occasion, but usually around 7500. I did not do any hard sustained runs like on a road coarse. Many trips down the drag strip, and some playing around on the street.

It is not like the stock exhaust will prevent you from making power with other mods up to a point. Doing so is not getting the most out of the motor or other mods. Uncorking a motor that inhales better will get considerable gains.
Click to expand...
The tune is everything. Like I said before, advancing timing up top was not making anymore power, so we dialed it back, keeping the engine as smooth as possible without sacrificing power. When timing is advanced too much, this will put more strain on the rods and bearings. I am not worried about revving this engine to 7800 rpm.

1vicissitude said:
No signs of detonation with 11:5 and pump?

Very impressive. Good job making everything work so well together.

Just 10hp shy of 949racings 182whp build. Which makes this even more impressive when you compare the two engines. Now I'm curious what that engine would have done with itbs and an extra point of compression...

This the perfect example of why building a 1.6 doesn't make a lot of sense.
Click to expand...
No detonation issues whatsoever. The car is tuned on 93 octane, which is available everywhere in CT. What was the specs on the 949 car? Was that the 2.0L?
 
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#11 ·
I would like to hear the OP, but would like to comment on some of the items.

I built a pretty healthy motor, and because I was on a budget, I stuck with the stock rods. I turned my motor to 8000 on the occasion, but usually around 7500. I did not do any hard sustained runs like on a road coarse. Many trips down the drag strip, and some playing around on the street.

It is not like the stock exhaust will prevent you from making power with other mods up to a point. Doing so is not getting the most out of the motor or other mods. Uncorking a motor that inhales better will get considerable gains.
 
#12 ·
so much awesome in this thread....so with the 99-00 head you wouldn't need a VVT tuner?
 
#14 ·
No signs of detonation with 11:5 and pump?

Very impressive. Good job making everything work so well together.

Just 10hp shy of 949racings 182whp build. Which makes this even more impressive when you compare the two engines. Now I'm curious what that engine would have done with itbs and an extra point of compression...

This the perfect example of why building a 1.6 doesn't make a lot of sense.
 
#18 ·
Will likely be stealing this set-up. I'm not even shooting for those goals with a motor, I'd be content with 160whp, nice to see that's realistically possible. I've always not wanted to build an engine for my track car because if it blew I'd be out a lot of money, but now that I've seen a proven OEM based set-up, I might have to give this a shot. Like you say all the stuff that could potentially break is OEM and easily replaceable. Chances of tossing a rod so bad it takes out the ITBs or something isn't likely.
 
#21 ·
I bet you when that one dude from Florida who spent almost $10k trying to build a 200whp motor (but ended up with a 180whp instead) stumbles upon your thread, he'll be kicking himself up the ass. LMAO!!!!
 
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#24 ·
I am pretty sure he went wrong with the cams. He was running 302' cams on 11:1 compression. He would probably need around 13:1+ compression for that aggressive of a cam. I said that to him in his thread, but he stopped posting a while ago.

silvermazda said:
Interesting answer. But would you mind answering all my question? It would really help me understand why it all works. And about the newb questions, please forgive. I'm just trying to learn.

Let me clearify a few things. About the rods. I'm worried about the stretching at high rpm. So I suggested using cheap forgies. They are similar in weight to stock rods. And as I suggested, just pulling them out, swapping them. Keeping the same bearings should theoretically keep the same clearances. I'm just saying as long as you have that engine open, why not bullet proof one of the only things that goes wrong with the factory bottom end?
-shouldn't take much longer or cost much in labor as the only thing needed are pressing the pins out and weighing the rods. -Now- I am not certain if this will need a full balance (pistons/crank/rods).
Click to expand...
You didn't read what I wrote above. Stock rods are fine at 7800 rpm with a good tune. There is no such thing as a cheap bottom end and certainly no "bullet proofing" as you keep saying. Throw that mindset out. The only reason to go with internals like that is when you are trying to exceed what OEM can do. By doing that you are accepting the price and the reduced longevity of the motor. Show me a built bottom end BP revving to over 8k that has 100k miles on it. I bet it doesn't exist. Plus, half the time something isn't balanced correctly, clearanced properly, etc. So you are already taking the chance that something will go wrong. Built motors cost a lot more money. Period. Built does mean better and certainly does not mean more reliable.
 
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#22 ·
Interesting answer. But would you mind answering all my question? It would really help me understand why it all works. And about the newb questions, please forgive. I'm just trying to learn.

Let me clearify a few things. About the rods. I'm worried about the stretching at high rpm. So I suggested using cheap forgies. They are similar in weight to stock rods. And as I suggested, just pulling them out, swapping them. Keeping the same bearings should theoretically keep the same clearances. I'm just saying as long as you have that engine open, why not bullet proof one of the only things that goes wrong with the factory bottom end?
-shouldn't take much longer or cost much in labor as the only thing needed are pressing the pins out and weighing the rods. -Now- I am not certain if this will need a full balance (pistons/crank/rods).
 
D
#23 ·
Nice build, Quinn. It is nice to see the final product!

I have the head built with Intregal cams and shaved only .020. I cleaned up the ports myself and gasket matched the intake and header to the head. Going for a .5 compression bump.

Looking for a tired 01 - 05 short block to rebuild using OEM parts, but am going to source some 84 mm pistons. I was going to balance the crank during the build.

I am going to use the toyota itb.

Thank for the post! Did you say the is a build thread?
 
#27 ·
Just out of curiosity. Pardon my ignorance on the matter. Would shaving the head as much as you did still maintain the engine as being a non interference motor?


Sent from my iPhone
 
#31 ·
The motor is now interference both piston to valve and valve to valve wise with the 10mm lift cams.

lowandslow24 said:
Very nice.

What is the stainless tank on the right side of the motor with the breather on top in the engine bay shot?
Click to expand...
Oil catch can

miata2fast said:
I think he did not quite have the combination of parts right, but I personally suspect there was something wrong with his tune as well.

Damn I wish he would get back on that project and start posting again.
Click to expand...
Yeah, I told him to just try a less aggressive cam as that would be the cheapest option, but he said something about rebuilding the bottom end with higher compression? For that money might as well of put an F20c in the damn thing. If I had to spend any more money I was just going to do that. I was actually really looking into it before all of this. The only thing that sucks is that it would have to be a lot of one fabrication to get it in there and if the car get's totalled you'd have to do it all over again to another shell.
 
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#32 ·
If e85 is readily available in your area I would love to see if you could make more power. Although since you said advancing timing more yeilded no results it may not.
 
V
#36 ·
Yeah, all of the Volvo "white" engines to present are interference. You have to make sure you change their belts at 100k, or you're playing with an expensive valve bender.

By timing correctly, do you mean just properly setting the stock timing on the belt change, or did you have to adjust the valve timing with your cam gears to get proper valve clearance throughout the opening and closing operation. I know you have valve to valve interference due to your higher lift cams, but because you're running more duration than stock, is the stock valve timing no longer correct for your application?
 
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#37 ·
vintagerust said:
By timing correctly, do you mean just properly setting the stock timing on the belt change, or did you have to adjust the valve timing with your cam gears to get proper valve clearance throughout the opening and closing operation. I know you have valve to valve interference due to your higher lift cams, but because you're running more duration than stock, is the stock valve timing no longer correct for your application?
Click to expand...
Stock valve timing is fine. With every adjustment of the gears, I spun the motor gently by hand to make sure nothing was touching.
 
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#39 ·
The dyno sheet shows the before numbers with the stock head minus the BP5A intake. I did the cams, head shave, gears all in one shot. More aggressive cams need more compression. My motor is still a 1.8L, if anything its a pinch less displacement because now the combustion chamber became smaller after the head shave.
 
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