Why am I only making 160WHP
 

Hello all

I recently install a flyin miata custom turbo kit on my 2003 miata. Below is a list of everything currently on the car. Initially I started at 4.5 pounds of boost and made 140whp. After I tuned the fuel table at 4.5 pounds I decided to turn the boost up. Now the car is running 8.5 pounds of boost but is making less then 160whp according to virtual dyno??? This is 20HP short of my 180WHP goal. The car pulls smooth it just isnt making the power I want. Also I think the spark plugs are showing signs of detonation? I have been running datalogs and my AFRs look fine, around 11.5-12.5 under WOT. The engine is in good condition and compression test showed 160 psi across all four cylinders. Any suggestion would be appreciated. Thanks

List of mods:
Flyin Miata Turbo manifold and downpipe
Flyin Miata Intercooler
Garret GT2560R Turbo
AEM FIC6 ECU
AEM X series wideband sensor
Cobalt Dual Tip Muffler
Flyin Miata Sway Bars
NGK BKR7E gapped to 0.032"

The Clutch and Cat are still stock. Below are images of my ignition retard map and also one of my spark plugs I pulled out today.






https://cimg9.ibsrv.net/gimg/www.mia...8e34851de9.png
https://cimg0.ibsrv.net/gimg/www.mia...186eb67c16.jpg

I am sure you know this, but your clutch will start slipping if it hasn't already. The added torque from the turbo isn't helping it hold, not sure if that's why you are short of your goal but it could be part of it.

Your comp test numbers make me think you may be at elevation. Where dou you live?

Like others said your stock clutch needs to me upgraded. Also you said stock cat and Cobalt muffler. You need at the very least a full 2.5" exhaust if not a 3". You will pick up 20-30whp from a proper exhaust. The plugs look ok, those speckles on the porcelain could be light detonation but it doesn't look bad to me. I'm not super familiar with the aem fic, i would think if your total timing at 8psi is in the 20* range you should be fine.

So far my clutch is holding rock solid. Knock on wood. When I did the compression test the engine had cooled off a little but was still semi-hot, not sure how much that matters. When I put some oil down the spark plug holes my compression went up to 170. I'm pretty sure the tester wasn't sealing 100% though because I could see oil mist coming out of the spark plug hole when it was cranking. I live near Phoenix AZ so i'm at little elevation. The gas here seems pretty terrible. The highest octane is 91 and i've heard the stock engine pinging on that stuff a couple times. The timing is basically the factory map plus the FIC map. So i'm running about 16-22 degress of timing in the 160 kpa row.

As long as the compression is even across all cylinders you're looking good. Your clutch won't hold when you get a real mans exhaust haha

Yes, the flecks on the porcelain are likely a detonation indication.

I don't know of anyone here running the FIC on our cars.

160whp is 200whp on a Flyin Miata dyno.*

If you were running a megasquirt we would ask you to post logs of the engine running and a copy of your tune. Pretty difficult to see what's going on without more help.

With the 1.75 in stock exhaust you aren't going to make any more power. You ideally need a 3in catalytic converter and Muffler through which a golf ball can pass unimpeded.

*That's a joke but it is very close to being true.

91 vs 93 also explains the difference imho. That plus blowing through a straw... Are we actually surprised?

Make sure your map is actually for the fuel you're using and not someone else's setup.

I would also think that you would need to upgrade your injectors. I know that isn't your problem now but if you are looking to swap out your exhaust and run near 200whp, the stock injectors won't do the job well.

Thanks for the suggestions. I couldn't find a AEM FIC spark map so I had to make the spark map myself. I have no idea what the factory spark map looks like so I had to guess when I made it. The fuel injectors are already at 100% under full boost so those will need replacing. I thought the stock NB2 injectors were good for 180-200WHP? I guess not.

I was running an MS3X for a short period before switching to the AEM FIC. I had a lot of issues with megasquirt so I gave up and switched. Currently I have closed loop AFR, open loop boost control, ignition mapping and fuel mapping with the FIC. The car runs great and the factory ECU takes care of all the other stuff I don't care about. In case you guys are interested I attached a datalog with some WOT pulls and the file can be opened with the megalog viewer.

What exhaust system do you guys recommend? I would like to keep the exhaust noise level down for highway driving.

Anyone know how much power the Tochigi-Fuji diff can hold?

I think i have the rules of thumb down correctly...but... stock clutch > stock engine > stock transmission. Thats the order at which things needs to get replaced as power goes up. Dont know much about diffs.

As far as exhaust...replace the midpipe with something at least 2.5". Make sure it has a resonator for extra silence...but the turbo should already be doing a good job at cutting decibels.

You should have figured out how to operate the megasquirt. We could have helped.

You won't make enough power with your setup to destroy the TF diff.

All stock injectors are tiny. Making much more than stock power requires raising the fuel pressure significantly and stock pumps aren't always up to the task. It is better to use stock pressure, 400-600 cc injectors, and a megasquirt for around 180-250whp.

For the exhaust a good "muffler shop" can make a 2.5" or 3" set up fairly inexpensive, throw a magnaflow muffler on the back ( don't remember the part numbers) and it won't drone or be terribly loud.

If you have a turbo and the big MagnaFlow we always use it will be quiet. The forum has a preferred model of MagnaFlow for quiet power.

Check fuel pressure?

Well, I put the car on jack stands today so I could track down a large oil leak that recently started. I started the car and noticed oil dripping out of the bell housing weep hole. Looks like i'm going to be replacing the clutch sooner then expected. In hindsight I should have did the clutch and rear main when I had the sub frame off. :vash: Is there any reason I should spend the extra money on a 3" over a 2.5" exhaust? I don't mind if the spool is a going to be a little slower. Also what are the limitation of 91 octane? I'm wondering if switching to E85 would be necessary to make 200+whp without access to 93?

More power at less boost, there's no more upgrading past 3 inches and I 100% disagree with you on the spool part. The response is fantastic.

91 octane is more than ok for 200 hp. Just make sure you don't yank someone's timing table that was built on 93 and you'll be just fine.

What on earth makes you think that removing restriction from the exhaust is going to cause the turbo to spin up more slowly? The opposite is true.

With a straight-through muffler (eg: Magnaflow), a 2.5" exhaust system will more than suffice for 200 HP.

I'll admit to never having used Virtual Dyno. Did you happen to do a baseline run before making any modifications to the engine?

I haven't used it either but he way I understand it the results rely heavily on the inputted vehicle weight. To make sure as much accuracy as possible I would get the car weighed.

If there aren't any DOT scales near your house you can pay for a cat scale at a truck stop. Pull up to the scale and stop so that the front and rear tires are on different pads. Hit the button for the intercom. They will ask if it's your first weight or a re-weight. Tell them first weight. They'll ask for a truck number, them re-weight. They'll ask for truck number. Make one up (007, 69, 420 A1... What ever). Park, go in and go the the fuel desk (register in the back near truck pumps) tell them you need your scale ticket, they'll ask for the truck number. The first scale ticket is $13 after that they are a dollar each. It will give total weight and weight per axel. I have access to one at my company that is accurate to 20 lbs. My car came in at 2220 lbs with a full tank without me in the car...

Many industries use vehicle scales. Scrap metal yards and places that sell or charge to dump bulk materials like sand, rock, or construction debris often have them near the entrance. Park and go in the scale house and ask nicely if you can drive across the scale and get the weight of your car. The display should be where you can see it while sitting on the scale.

Ok let me rephrase that, IMO the faster spool of the 3" isn't worth the extra cost. So I'm probably going to get a 2.5" midpipe and see what happens. Not sure how restrictive the cobalt muffler is but if it becomes a problem then i'll remove it. I did do some virtual dyno runs when the car was still stock and it showed 107-109 at the wheels. This makes me think that it is pretty accurate.

So, to summarize the thread to date:


Using an app on your phone, you estimated the output of an unmodified '03 Miata at 108 HP. That's within the realm of plausibility.

You then bolted on a turbocharger and increased manifold pressure by around 58%. Despite the fact that you've made no upgrades to the fuel system, are running a somewhat restrictive exhaust system, and are clearly pinging, you still managed to increase HP by around 47%. That's also within the realm of plausibility.


What about this scenario is confusing?

Nothing is confusing. I just thought 180whp was attainable with my current setup. I clearly need to make some upgrades before I can make more power. Later this week I will dropping the transmission and putting in an ACT HD street clutch. While I've got the exhaust off I will also be swapping in a FM 2.5" midpipe. And to top it off I will install some new forceflow injectors. FYI virtual dyno is not an app on your phone. It is software that looks at a datalog and then computes your whp based on the datalog.

Virtual dyno is only as good as the data you feed it

Coming from someone who makes miata exhausts, the cost difference in material between 2.5" and 3" is extremely small. I would go 3" all the way back. Yes it does make a noticeable difference.

Virtual dyno requires a flat road on which you can safely make full-throttle accleration runs up to over 100 mph without any legal consequences. It also requires an accurate weight for the car as well as an accurate coefficient of drag. These are not trivial things, and hoping to get a number you can compare to a dynojet on your first try is asking a lot. While there are people on this forum who have had success with virtual dyno, personally I have never managed to get a reasonable number out of it.

While it is theoretically possible to get 180 rwhp out of the stock injectors, that assumes you've got the car tuned ideally and that the rest of the system is built out not to present limitations, and a stock exhaust doesn't qualify. Personally I have reservations about a piggyback system like the FIC ever providing enough controllability to do that. The problem with this kind of thing is that it's programmed as a series of deltas off the stock ECU's output, and the stock ECU is not totally predictable. Timing is trimmed by many factors like intake air temp, coolant temp, time the car has been running, etc. You don't know what all of the tables in the stock ECU are, so you can't ever know exactly what timing value it's going to give you. Imagine a given cell normally gives you 24 degrees, but maybe one day it gives you 25 or 26 instead, another day it gives you 23. To accomodate this you can't tune a piggyback system to the limit of detonation, you need to leave 3-4 degrees of safety margin in to prevent it from pinging itself to death on the day when the ECU gave you 27 for no reason you can figure out.

Other complications of a piggyback system include that it's difficult to change injector sizes, and that you need to keep the stock MAF in the intake. The MAF is restrictive, and once you hit around 220rwhp the stock ECU will stop believing the signal that it's sending and take away all the fuel.

I had a system similar to this (a Link Piggyback) many years ago and after a few years of tuning I outgrew it and moved to a full ECU (first Hydra, now MS3). Piggybacks are great for the reasons you listed -- simple to set up, stock idle, etc, and they can work very well for someone who isn't interested in ultimate power, but just wants to add 40-50 hp without having to think about it too much. If you're worried about 160 vs 180 rwhp, well, a piggyback is probably not the right solution for you.

My advice is to get a 3" exhaust (yes, the small additional cost is worth it), a set of bigger injectors, put the MS3 back in, and spend a few hours tuning it on a real dyno. 230-250 at the wheels awaits. :)

--Ian

Ian,
I agree with you on the piggyback ECU. It only gives you so much control over the stock ECU and is really just a delta map, not an actual map. This car is my DD and street driveability is very important to me. When I had the MS installed the car would often stall and buck at low speeds. This is ultimately what made me switch to the FIC. I'm thinking about giving MS anther try but I don't want to waste time if OE like driveability isn't possible.

While the MS3 is never going to have 100% of the drivability of a stock ECU (*), there's no reason it can't be tuned well enough to be a perfectly usable DD.

--Ian

(*) This is IMHO. Note that there are other people on this forum who would disagree and say that it can be BETTER at drivability than a stock ECU. Maybe they're better at tuning than I am, or maybe they just have lower standards, I'm not sure.

Better than stock is achievable but it takes a minute. Close enough for happy smiles is pretty easy.

Just took the car out for one last drive before dropping the tranny and replacing the clutch. It seemed to be down on power a bit and not running like normal.. After about 15 mins of driving the CEL light came on. Just scanned it and got P0012 intake cam over retarded?? :crx: I recently took out the oil plug out on the back of the VVT so I could check my oil pressure. Not sure how this would have killed my VVT but it's the only thing I can think of.

Not sure what the problem was but I got my VVT working again. I redlined the engine a couple times and manually supplied 12v to the solenoid to verify operation. The car picked up a bunch of low end torque after doing this. Maybe some air got in it and was casing the issue? Now its time for the clutch replacement.

Aka also time for ECU replacement.

The 'trick' with a standalone is to limit what you change so you can tune for a singular variable everytime, get that down, and then move forward.

You can get away with swapping pump and injectors together if the data on the injectors is bullet proof.

Do too much at once and you have a headache because it's next to impossible to figure out what's causing what deviation... Unless you really know what you're doing and have some good base stuff to figure out from.

If it helps, my car is also disappointingly slow. But hey it makes angry turbo noises :bang:

My Hydra has 99% like stock driveability. Granted it took a long time to get it to that point. The only issue I have is on cold starts the car isn't perfect, cranks more than it would with a stock ECU. Other than that for a car with 300hp I think it's pretty darn good. Ditch that piggyback

I just finished pulling the tranny and clutch out. The clutch was almost worn down to the notches and the flywheel has some grooves in it. I got very worried about the transmission when I felt some play in the input shaft but after doing some research I guess this is normal?:confused: There is about 1/8" to 1/4" of radial play and no axial play. When I spin it by hand it feels smooth but lumpy at the same time. Could someone confirm that this is normal for a 6-speed? I don't want to reassemble everything if the tranny is toast.