Terrible top end only 140whp?! Doesn't make sense
#41
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Not ideal, but i'm going to assume you dont want ti crack the case open and count the teeth.
Otherwise, chuck it in 1:1 gear (4th on a 5 speed, 5th on a 6 speed) and do 60mph (assuming wheels/tyres with the factory 576mm diameter)
4.1 will be at 3625rpm
3.9 will be at 3448rpm
well, around those numbers anyway, tyre pressures/sizing and all that **** depending
#44
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Join Date: Sep 2017
Location: Baltimore; States
Posts: 190
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So when u hook up a compressor to the intercooler piping (in my case i did it at the very start of the intercooler piping) you're not supposed to hear any air escaping through the throttle body/iacv?
I've always assumed the air that goes past the throttle body gets into the intake manifold, goes through 4/8 intake valves, depending how the engine is clocked, enters cylinders and oh yeah, in fact if air can enter the combustion chambers via intake valves due to paused rotation of the engine, then it wouldn't be able to exit because the exhaust valves should be stuck closed for the cylinder that's intake valves are opened.
Okay as for my pcv system reasoning at first, i assumed it was possible for air to get by the piston rings and end up in the crankcase to vent out the valve cover breathers.
But again, in theory that shouldn't happen.. Bcuz when I do a compression test, they all hold over 180+psi of pressure.
When i rebuilt the engine, the cylinder head was placed upside down and i used xylol (xylene) aka paint thinner to fill up the valve seats with thin solvent and nothing leaked through. The valves held shut and kept any leaking very well.
I'm thinking the air leak must be from a combination of ebay tbolt clamps on my intercooler couplers or something intake manifold related.
Anyhow i only run 10-14psi of boost on average and that amount of air flow far far exceeds loosing about 1psi every 15-20seconds when charging the system up to 20psi via air compressor.
Besides the MAP sensor and interior boost gauge use different locations and they are quite accurate. It isn't a boost leak that minuscule that's ganna keep me from making 190-200whp; especially when the map sensor/boost gauge vacuum inputs are always on point. It's just not so. I'm sure it will help with spool up when i fix that tiny leak but it was very small. Overall i was impressed with how good everything kept over 20psi of pressure.
As for not making 200whp, I'm thinking it's virtual dyno settings and the quality of the data captured... Bcuz when i take those same logs and reduce the smoothing to 0, it shows crazy looking spikes and a ugly graph but the spikes read out power levels that seem way more realistic. I think it just has to do with getting the perfect datalog in order to set the smoothing at 1 or 2 and get back the right power levels. Whatchu think?
I've always assumed the air that goes past the throttle body gets into the intake manifold, goes through 4/8 intake valves, depending how the engine is clocked, enters cylinders and oh yeah, in fact if air can enter the combustion chambers via intake valves due to paused rotation of the engine, then it wouldn't be able to exit because the exhaust valves should be stuck closed for the cylinder that's intake valves are opened.
Okay as for my pcv system reasoning at first, i assumed it was possible for air to get by the piston rings and end up in the crankcase to vent out the valve cover breathers.
But again, in theory that shouldn't happen.. Bcuz when I do a compression test, they all hold over 180+psi of pressure.
When i rebuilt the engine, the cylinder head was placed upside down and i used xylol (xylene) aka paint thinner to fill up the valve seats with thin solvent and nothing leaked through. The valves held shut and kept any leaking very well.
I'm thinking the air leak must be from a combination of ebay tbolt clamps on my intercooler couplers or something intake manifold related.
Anyhow i only run 10-14psi of boost on average and that amount of air flow far far exceeds loosing about 1psi every 15-20seconds when charging the system up to 20psi via air compressor.
Besides the MAP sensor and interior boost gauge use different locations and they are quite accurate. It isn't a boost leak that minuscule that's ganna keep me from making 190-200whp; especially when the map sensor/boost gauge vacuum inputs are always on point. It's just not so. I'm sure it will help with spool up when i fix that tiny leak but it was very small. Overall i was impressed with how good everything kept over 20psi of pressure.
As for not making 200whp, I'm thinking it's virtual dyno settings and the quality of the data captured... Bcuz when i take those same logs and reduce the smoothing to 0, it shows crazy looking spikes and a ugly graph but the spikes read out power levels that seem way more realistic. I think it just has to do with getting the perfect datalog in order to set the smoothing at 1 or 2 and get back the right power levels. Whatchu think?
#45
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Thread Starter
Join Date: Sep 2017
Location: Baltimore; States
Posts: 190
Total Cats: -35
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Problem FIXED!!!!
so i just wanted to follow up incase anyone was having the same exact problem.
It was the mechanical timing for me.
The crank pully was mechanically timed as advanced 10degrees. And the camshaft pullys were angled properly in relation to (if) the crank was at proper TDC.
But because of the way it was oriented, both of the cams were like atleast 5 degrees retarded. If I'm not mistaken.
Anyhow i fixed it and It's timed right mechanically.
And the ignition base is right with 10 degrees of spark advance before tdc.
Basically, before i had the crank clocked the way you'd want it to appear when u were doing timing with a timing light.
So does that mean exactly that this whole time the entire spark map was running 10degrees retarded across it?
Or i think it meant that the spark timing was still correct, just the cams were both either advanced or retarded like 5 to 10degrees or something lol
If anyone else can elaborate and picture it in their head better than i can plz do![wink](https://www.miataturbo.net/images/smilies/wink.gif)
But anyways!
I put the first spark map back on that i had all the way from the beginnings.
After the first pull at only 9.5psi (and only up to 6k rpm)
It made 203whp / 190wtq with VirtualD filtering set at 2 or 3. =)
Bingo was his name-o
Thanks everyone. I still learned a good amount from this thread
And this fix happened by chance, the cheap dnj timing belt snapped and so when i put the old oem timing belt back on and re did the timing, that's how this got discovered haha
so i just wanted to follow up incase anyone was having the same exact problem.
It was the mechanical timing for me.
The crank pully was mechanically timed as advanced 10degrees. And the camshaft pullys were angled properly in relation to (if) the crank was at proper TDC.
But because of the way it was oriented, both of the cams were like atleast 5 degrees retarded. If I'm not mistaken.
Anyhow i fixed it and It's timed right mechanically.
And the ignition base is right with 10 degrees of spark advance before tdc.
Basically, before i had the crank clocked the way you'd want it to appear when u were doing timing with a timing light.
So does that mean exactly that this whole time the entire spark map was running 10degrees retarded across it?
Or i think it meant that the spark timing was still correct, just the cams were both either advanced or retarded like 5 to 10degrees or something lol
If anyone else can elaborate and picture it in their head better than i can plz do
![wink](https://www.miataturbo.net/images/smilies/wink.gif)
But anyways!
I put the first spark map back on that i had all the way from the beginnings.
After the first pull at only 9.5psi (and only up to 6k rpm)
It made 203whp / 190wtq with VirtualD filtering set at 2 or 3. =)
Bingo was his name-o
Thanks everyone. I still learned a good amount from this thread
And this fix happened by chance, the cheap dnj timing belt snapped and so when i put the old oem timing belt back on and re did the timing, that's how this got discovered haha
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