Terrible top end only 140whp?! Doesn't make sense
 

Not sure if I should just throw more boost and timing at it to try and force the graph to look proper when there is most likely an underlying problem. The log shows with RPMdot that there is something fishy unknown going on. I could really use some help please
obviously but something is not how it should be.

In a third gear or above pull the RPMdot always shows several points where the value is negative. Especially above high 4k to 5k RPM. It does not do this in a 1st or 2nd gears pull.

Several things tried already: I've gapped the plugs down to 0.032" all the way down to 0.027" as well as tried increasing the nominal dwell settings up a sensible amount with no good improvement. I can still shorten the spark duration although I wouldn't be SHOCKED if that doesn't help. ;) Anyways, also when dragging the pull logs into Virtual Dyno, it shows how the tq/hp looks (not good). Not only the peak figures but the shape of the graph overall doesn't look right for the boost, timing and setup I'm running. It should be more around 200whp+ and continue to climb as the boost slightly tapers higher towards redline.

Summary: I don't know what's causing this. Could detonation cause this? I checked in the combustion chamber with a mini HD camera and there is no pitting or signs of detonation other than a healthy looking engine. The compression is 182 on one cylinder and 195's on the other 3.

I'm running 93octane and using conservative boost/timing. Is that what a misfire looks like in logs? If it is a misfire, it's happening right when 1-2psi of boost builds but is intermediate. Enough to create a lack of power but not enough to ruin the livability a noticeable amount (at least until I can experience how it runs after this problem is fixed) Not sure what it could be. Wants those normal/good peak hp numbers for the top end!!

Oh and it's also important to note that I've checked for spark latency correction and the timing stays fixed properly at 10base timing with the value of 40 that the Megasquirtpnp.com turbo base map included so I've left that how it is (it shouldn't be latency correction).


https://cimg6.ibsrv.net/gimg/www.mia...1fc4f8366a.png

I just did two more pulls today with the boost turned all the way up, got the AFR's between 11.8-12.0 so there is no excuses. 16.5PSI and only 170wTQ?!!!! What the bleep.


That is definitely way too much boost for my stock internals and it still barely takes the numbers up to what you'd expect out of ~5-7psi power levels.

Soft top is up, windows were up, pop-up headlights were down, flat road and 3rd gear pulls.

3" free flowing exhaust, turbine and exhaust housing should be more than large enough for 300whp, 2.5" FM cast downpipe, cast log ebay manifold, stock coil packs, NGK plugs and wires, MS2PNP, Flowforce 640cc's which by the way, show a duty cycle of 89% at the peak of the boost it hits.

Anyone know what's causing this?

I should certainly have a 4.10 Torsen, 5 speed gearbox, 205 50 r15's on 15x8 rims. Weather is usually between 80-90degrees outside lately. That's everything I can think of right now.

virtual dyno?

https://cimg1.ibsrv.net/gimg/www.mia...905e005248.png

I mean, at 17 psi you're only asking what, 10 degrees of timing? I don't think you should be surprised.

Add 4* from 100kpa up, see what happens.






<---not responsible for what happens.

Add 6 degrees at 100kpa to end up where the spec Miata guys run. Get some det cans and try what Curly suggested.

Is virtual dyno set up properly?
Vehicle weight and wheel/tire size settings make a HUGE difference.

What's overboost protection set at? From the jiggly psi log right at 180kpa and seeing VD set at smoothing level 5 I feel like that's likely the issue.

From all of the other timing maps I've seen that others run to get anywhere from 230-250whp at the same boost levels i ran previously; 10 degrees at 200kpa should be completely good enough for for a baseline 200whp pull...

10 degrees should definitely make some proper power (above 270whp) when u throw 16.5psi at it.

This is all from my understandings.

I'm fairly sure that if i start adding 1 to 4 degrees at it, It should lively it up in increments and overall engine sound but something tells me based on ^^ up above, it's not the fix to the problem. And won't bring me to where i should be. At the very realistic risk of doing perminant harm to the car.

I need to make some det cans soon but i can't really go forward when the timing and boost should make atleast 40% more wtq/whp

Like i bet u if i added 4-5degrees it's not ganna bring it up to 210whp @ 16psi.

Idk i just think it's risky to do that when it should've made tons of power at 15-16psi with that spark map!
Right??!

I turned it up to like 230kpa? Just when i recently tested bringing up the boost by a large amount. It's plenty above where it needs to be.
16.5 should be borderline limits of stock rods even with 10degrees timing. Right? It was only a test

11.5psi made like 160whp
16.5psi made 169-179whp

As long as overboost is above the psi you're running then that shouldn't be an issue. It just looked like a possibility when I saw the log.

Inb4 op posts "blew my motor trying to make 200whp"

Sounds accurate haha. The timing boost is beginning to sound like a decent enough idea..

If i have time tomorrow after work if the weather allows, I'm ganna aim to first set the boost controller back to start at ~10psi with a less aggressive taper = ~12.5psi peak.

Do a base line then add about 1 to 2 degrees in two test runs and see how much it likes it. If it likes it by 2.0 - 5.0 whp per added degrees, then no. Not going further. Ganna put it back to where it first was & try to get LS coil packs soon.

But on the other hand if it adds at least 10-15whp or more per 0.5 to 1.0 degrees added then yeah I'll believe it was the timing all along /me shrugs.

In theory, if it is timing that's the problem, then adding only a few degrees should def bring me to 200+ easily no hassle

Thx | will be reporting back!! #WBRB

Back when i had the car on the stock ecu for a little while after freshly rebuilding the engine, i accidentally had the base timing set to 14-16degrees. There was 93 in the tank. I added some 89 to save some money, figuring nothing much of it. I drove to some backroads and it sounded happy during the trip there but Once i was in the twisties and put load on the engine, to get up hills and stuff, i felt the power disappear and heard the metallic rattle snake noise coming from somewhere lol. Realized after about 2 minutes what it was an limped home to fix it. It was only happening when i was going up any kind of hills.

Thankfully no damage occurred because it wasn't boosted and i wasn't really pushing it too far. That was way back last summer. Anyhow i know what the noise sounds like. I freaking felt it and heard it at the same time. But now days the car has aggressive poly engine mounts, tons of NVH, wind noise tire noise etc so I'm not ganna get as much of a notable difference if it knocks especially in boost. So i have to try and be smart about it and be as cautious as i can be. (KNOCK on wood)

You only hit 89% injector duty cycle when your shitty TPS signal spikes and triggers AE. You are, however, reaching 82% duty at 11.5 AFR with gasoline on 640cc injectors.

That much fuel should be good for very roughly 325-350 crank HP. Your logs look closer to what I'd expect a 4th gear pull to look like.

As for the excessive fuel spike due to AE; I plan on fixing that better once the fuel table is better once the timing is closer to what I will use. XD


I promise you it's third though lol thanks for looking into it tho. Forgetting the fact that if I did a 4th gear pull out to 6-7krpm, i'd be going 80-99+MPH. Nah I can't do that around here that many times lol or at least not without being seen. I can only do 4th gear pulls to like 5.8k without going too far over the spee limit RPM so i stick with 3rd gear for Virtual dyno logs

Got a random question. My tach is always kinda wobbly around 4k rpm but it seems to smoothen out above 6k to 7k. Do you think that noise is translated into a tuner studio log? Ideally I understand there should be no noise bcuz noise is in actuality a circuitry problem in the hardware that needs to be addressed rather than just tuning out the noise on tuner studio. But can that noise translate to the log and then its what's throwing off the power in virtual dyno? o.O

Idk I think I'm just missing fire and it's ruined the power. /me shrugs | Hopefully today I can add a little ignition advance to see if it adds tons of power per degrees (with the boost lowered a lot).

That sort of proves that it must be spark timing or misfire related (spark blow out)

So I brought the boost back down to the reasonable 200+whp levels I started off with today; like 11-12psi but also added around 4degrees in the 100kpa row. And anywhere from 1.0 to 2.0 in the 128kpa and above rows. The results of many logged pulls only yielded a net gain of a 2wtq peak more than the previous timing at the same PSI of boost. Therefore, if I were to chase more and more timing, I should most likely hit detonation before achieving 200wtq levels. Estimated. Doesn't that logic seem reasonable?

Doesn't seem like it should be so difficult to reach 190-200+whp with a standalone, 640cc's, semi large churbo, free flowing exhaust, running similar spark advance as others who are able to net much more than 200whp at the same boost, unless there is misfire the moment it runs above 100kpa; right? But if it was misfiring I'd expect to see the AFR readout in the logs and VE Table to hint more at it rather than looking kind of normal.

It's either intermediate spark blow out at low to high boost levels through out every pull OR the settings I have in virtual dyno are off by a lot. Has got to be one of the two o.O;; It does feel like it runs good.

In virtual dyno I noticed the RPM difference between the peak HP and peak TQ is a longer distance apart from each other now with the added timing. For example, before it was only 400-500rpm apart from one another. Now it's more like 1,000RPM different. That's probably good

When I added the timing advance, the IAT's / MAT's finally went up a whole lot more as the boost & RPM climbed in the logs. Rather than before I would never see more than 101 degrees f after several boosted pulls. Note that my intercooler is rather large 28" with 2.5" inlet/outlets. Where as today I finally saw 110degrees f during one pull and that excited me. It also feels faster but virtual dyno just says it barely added 2wtq at the peak. I'm still only at like around 173lbft and 179whp @11-13PSI. The added timing definitely increased MAT's somehow... Could that clue into any answers?

Don’t look at peak, that’s only half the story. Post the new graph. If you had a misfire, you’d see a dip in power and torque. Your issue sounds more like incorrect timing or some sort of clutch slip

What rear end do you have? Also 2500lbs seems heavy for an na8.

Rear end is 4.10 Torsen which came stock with the car. I'll try the ratio of the viscous LSD and see if that makes the graph look more realistic but it's likely not that final drive bcuz the car drifts and handles perfectly fine even with the boost.

The clutch is a sprung 6 puck with stock flywheel. The pressureplate and clutch is rated for like 280ftlbs of torque and only has around 10k miles on it or less (and was broken in properly).

Plus if the clutch slipped you'd feel it the revs definitely don't spike up or anything lol it grabs really hard all the time.

Here's the VD screen shot. The first 2 pulls are the baselines after I added some timing @ 11-13 PSI. And the last 3 pulls are after I added even more timing. Same boost levels. Same day. The smoothing at 2 is similar to smoothing 5. So I took the screen shot at 2.

https://cimg5.ibsrv.net/gimg/www.mia...39f278f8e9.png



Here's the timing before, this is the same map I used when I did the 16.5PSI runs and got nearly the same power as 11-13psi.
https://cimg4.ibsrv.net/gimg/www.mia...e62b86d101.png



And the timing afterwards, I set the boost back to 11-13psi did the first 2 baselines then added all of that advance and still only netted 2wtq. I feel like if the problem were the advance, you'd yield a whole lot more than 2wtq overall. More like 10wtq+.

https://cimg2.ibsrv.net/gimg/www.mia...e192241066.png

Be honest guys, don't try to push me to add more timing lol You know I should have 200whp with that spark map and 11-13psi of boost taper. Plus I personally know I can keep the advanced timing table it has and up the taper to 16.5psi again and still not hit that close to 200whp. Something is definitely wrong with either the ignition system or the virtual dyno settings.

Oh and to go back up a couple of posts to where somebody asked why I had the weight set at 2500. That's because I have a whole crap ton of stuff in the car that should add about 100lb roughly. I have the low-profile harbor freight jack in the trunk and my tool box which adds roughly 100lb. So I figured I'd up the weight to play it safe but it still doesn't make that much of a difference.

It did actually add about 9.0 WHP at 6500 RPM when I changed the 13.0 timing at 184kpa to 15.5 of advance at 184kpa (after comparing a few logs to one another).

But the peak numbers/mid range stayed about the same. Perhaps going by that, I could rule out that the mid range wants more timing, but the top end likes it. Ganna see what I can do.

Can anybody suggest a spark map for me to try out today? If you promise to keep me within what you know for sure as a safe limit. Just a turbo base map that should be relatively safe for 91-93 octane yet still easily produce 190-200whp with before hitting the dyno; i would very much appreciate that! I use 93 octane.

I've always thought that you can make 200whp at conservative timing (pretty much base map) as long as you have your boost at around 11-12 psi. Heck I've tilted my spark map a fair amount more aggressive than the turbo base map and even tapered the boost as high as 16.5PSI without going near 180whp. @_@

This should be easy to solve

Usually N/A timing (100kpa) is around 28*.

Usually your rows go up by 2-4psi at a time. Yours are 4psi

Usually you go down 1 degree for every psi.

Your 100kpa row doesn't look terrible. Copy it to 128, 156, 184, 212, and 230. Then take 4, 8, 12, 16, and 18 degrees out of those rows respectively across the board. You'll want to taper the higher KPA rows up because you'll be negative and even though you'll never hit those high boost numbers at lower RPM, I hate having negative timing numbers on my map.

Get your car weighed, check mechanical timing, then check leak down and compression, we can't help much more until all of the above is done. And don't like, get back on the internet and start arguing with me, go out to the garage and start working on the car and test/fix/measure these things.

^ what he said

Although I'm on team "blow it up" for the sake of my own pretentious entertainment.

Thank you!! That's a nice guideline to use. Appreciate it

Compression is 195ish on 3 cylinders and 187ish on 1. I hooked a air compressor up to where the intercooler piping begins out of the turbo outlet and BOV/intercooler piping doesn't have boost leaks. There was some constant air escaping somewhere post-throttle body though. I was pretty sure that should be normal.

As for the mechanical timing, I used a timing light on fixed timing less than 3 weeks ago to rev the engine RPM high to make sure it wasn't a spark latency correction issue. I did 3 tests and they all looked to stay fixed at 10 degrees of advance. Tried my best to slowly increase the RPM's then Even bounced off rev limit during those tests.

The weight of the car isn't too important if you've ever added or removed a couple 100 lbs you'd find that it doesn't have a huge impact on the VD reading. So as long as you're in the ballpark of give or take 100-150lbs it's ganna be close enough. What's more important is making sure you do a pull on flat ground. And probably the aerodynamics effects of 3rd, 4th gear pulls. I keep everything as constant as I can. One time I did a 3rd gear pull down a mild hill and it read more of what I'd expect to see ~300whp lol

Only thing mechanical I think is left to check is make sure the timing belt isn't off by a tooth (maybe the crank pully top dead center mark is clocked roughly a tooth off too advanced or retarded in comparison to where the camshafts should be and if that's not it then idfk should I get LS coils @_@

It runs and sounds good that's the part that makes a lot of things seem out of the possibility

I meant crank and cam sprocket timing

Yeah good point. I'm ganna try to check that today after lunch before I even do more spark advances. If it looks like it's off I'll try to take a picture for reference and post on here. If it seems to be off, I'm not ganna keep pushing the timing. Gotta fix that first!

In theory, if it is too advanced or retarded by being off mechanical timing, wouldn't the aftermath be something like a better mid range for a lesser top end or vise versa or would it mean that the base timing is not actually true. Or would it result in both of those things being the case lol It's a 95 1.8l with a CAS.

Honestly that looks like a BEAST table for a turbo base map lol

https://cimg8.ibsrv.net/gimg/www.mia...82a08d910d.png




But this is the most I'll be willing to push it (If the mechanical timing looks right).
https://cimg8.ibsrv.net/gimg/www.mia...cdd29ee061.png

I just got done checking the mechanical timing. The #1 cylinder goes up to TDC, right about when the 2 timing marks on the crank pully lines up to the meter on the black plastic cover. Right when the camshaft sprockets hit their marks. I'm actually surprised it's better timed than I remember being able to get it at the time. I was struggling to get it as good as I would've liked when I remember back but it turned out good from the looks of it. It's not like it's backfiring or anything when the low kpa and cruise regions are of decent spark advance. Runs good.

All that's left really is to narrow it down to spark blow out (need to buy LS coils) or Ignition timing (about to go out and try out the more aggressive map and HOPE it doesn't bite me in the ass really bad bcuz the Miata is my only daily right now to get to and from work... stupid, yes)

At this point it can't be Virtual Dyno settings because so many people have looked over the datalog in their own VD and didn't find anything irregular.

Will report back in a couple hr on how the advance goes! Ganna drive to dunkin donuts & re-adjust the fuel table for it, grab a coffee and then go do several pulls at the normal place!

I finally actually looked at your log instead of just glancing at the tables you posted, is there a reason your MAP signal starts oscillating at 4800RPM? It starts as a slow ~2kpa oscillation, but from 5800 to the end of the pull you go up and down 10kpa 4 times. It starts right when your boost duty starts coming up to maintain boost at higher RPM. Have you done any tests to verify that you can't go above 0% DC without affecting boost? You're boost duty cycle map has you going from 0 to 21%DC in 1500rpm.

Yeah i just started using the EBC solenoid not very long ago. It was when i installed it, and started to use it that i started to try to tackle the reason why virtual dyno never shows nearly 200whp for me. Ever since i started to work on that problem, it's been my major focus and distracted me from really dialing in the EBC duty table anymore than when i first installed it. That oscillation is from the boost solenoid because it never did that when it's only on wastegate spring pressure.

When it's on WG, the boost slowly climbes to around 190kpa peak and doesn't oscillate. It's like a 10-11psi spring i think but i can adjust the preload to get it to function at between 8-14psi.

Do you have a log of it running on the wastegate? That'll help set the boost duty table up, along with finding what DC actually starts to produce more boost when the EBC is hooked up.

Did you see where he said he had a boost leak but dismissed it as being normal?

If you plug an air compressor and run compressed air through your intercooler piping, it's going to come hissing out of your PCV valve and crankcase vents.... What did you think I meant? "Oh, I heard air but no boost leaks, nope" You must of read like half of the sentence lol

Btw reporting back, the increased timing didn't help much today either. I used the more aggressive map and it added maybe 5whp to the top end (averaged). Mid range still the same as before for the most part. Still running boost at between 11-13psi constant

I noticed something 10mins ago tho if I change my final drive ratio on Virtual Dyno to 3.9:1 it starts to look more reasonable. o.O
But I should 1,010% have a 4.10:1 final drive. Torsen diff.

I am the 7th owner of the car tho that I am aware of. It's a early 95 1.8l. What's the odds that a previous owner changed the final drive gears when the car had lower mileage? Pretty slim meh

I'm coming to the conclusion tonight that I just haven't been plotting accurate enough VD logs. If I get time tomorrow, I want to try and find a better suited road. Try not to turn or wiggle the steering wheel at all, and see if I can plot something better. Will report back in 1-2 days.

I'm interested to hear your theory as to why air coming out of your PCV while pressure testing your intercooler piping (preferably to at least 20psi to be on the safe side) is normal.

Regarding the gearing, you have an ECU that can accurately tell you what RPM you're at. I would just GPS your speed and compare your RPMs to what they are to what they are supposed to be. 4.1 is 3400ish @ 70 and 3.9 is 3250ish @ 70.

Me too.

Only time you'd expect it is if the hotside rocker vent is plumbed into the intake somewhere, like the OEM system.

The quick and shitty way to check the ratio is to rotate the tailshaft once and count how may times the wheels rotate.
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 shit depending

Sure, but that's A) not where i'd be testing and B) not what we're referring to when we say "PCV."

True, but i've seen people do weird shit when it comes to the Rocker vents.

(also, fair enough re: part B, i've always referred to the whole lot as the PCV system, since it's all linked/related anyway)

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?

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 ;)

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