Power issues with EUDM VVT I/H/E + MS3
 

After dynoing my EUDM NB2 I had some really low results.
Modlist:
Rev MS3Basic
Simple 180 degree "cold side" intake (similar to what 949 used on their TH car, not ideal length for now so there is the classic torque dip at ~3500rpm), no MAF
Japspeed Ebay headers (same layout as stock EUDM vvt tubular headers)
Stock Cat
Custom straight 2.375' ID midpipe
Custom straight through (perforated) 2.5' ID muffler.

Misc items:
New (~15k km) NGK Iridium Plugs (same heat as stock), replaced stock cables with Magnecor at same time.
5W40 Shell Helix/Rotella Oil
Setrab 310mm x 19row Oil cooler with Mocal Thermostat plate and -10AN Lines
'Ebay' 52mm Radiator, 10% EG Coolant
Waterpump, Belts, Pulleys, Tensioners replaced 15k km ago.

First Dyno was a Dyno Dynamics, values are STD Corrected and are Flywheel HP:
https://cimg7.ibsrv.net/gimg/www.mia...9c74f70931.jpg


The Pink line is a Fully Stock + Racing Beat muffler NB BP4W done during similar environment conditions (but not same day)
During this dyno there were a few other cars, a low mileage S2000 AP1 that put out 242 flywheel HP, some 1.5 ND miatas putting out 128-135hp, So the Dyno seems to be decently well calibrated.

Noticeable, the +20NM torque @ 2500rpm, and a decent torque margin all the way to 5500rpm, but then the line follows exactly the same as the NB1.

Went to another Dyno just to get another baseline (seeing as the other dyno is used by other people I know, its nice to have a baseline for comparison purposes)

Dyno is a "Bapro", unknown. Values are in line with the Dyno Dynamics.
Blue Line is WHP, White is Flywheel HP, Green is "Loss" from what I understand.
https://cimg3.ibsrv.net/gimg/www.mia...6d20a9d2b3.jpg




Before going to the dyno, I fully tuned the car, it drives perfectly smoothly, even smoother than Stock since my EAE is tuned to near perfection. The car feels more powerful, but I cant really say it pulls any harder at redline than stock.

Doing some Virtualdyno pulls with timings from the Rev basemap (~26 degrees at 7000rpm), after everything else was tuned, it measuring average 135whp, up and down same street, same 30 minutes, 3rd gear, driver and car weight were accurate (measured with truck scales at 1040kg with half a tank + 75kg driver).
After adding about 4 degrees of timing from 3000-redline it went up to ~140whp. Tried adding another degree or two of timing but no power increase, so its fairly close to MBT

Some of my tables:
Attachment 229725
Attachment 229726
Attachment 229727

AFRs are stable all the way at 12.8, I have full time EGO closed loop control.
VVT angle is about 4.7 degrees at redline (so you dont have to interpolate :P)
Injector timing is 360 on all cells.

Im Stumped as to the abysmal result, how can so much more timing over Stock, seemingly at MBT, none of the stock intake restrictions, very little exhaust restriction post cat, produce such results?
Could it be the shitty Ebay temporary intake? The Cat is clogged (looked fine few months ago before MS3)?

After the first dyno, I ordered a compression tester, will do that and attempt a leakdown test.
A racing beat header will also be purchased and will be installed with a custom test pipe to mate with the custom midpipe.

Any other ideas on what it could be?

Honestly, seems inline with shitty intake and headers (Why switch an eudm header? Only for a racing beat and still the gains would be minimal).
​​​​​

The intake isnt shitty, its been tried and tested in this forum and others many times, it just lacks the correct length leading to torque dip at 3500rpm, it doesn't have any negative effect at high RPM.
Attachment 229724
Its a temporary intake until I can make one the correct length out of aluminium instead of silicone.

The header was replaced because it was very rusty and impossible to replace without cutting.

These power levels are extremely out of target compared to similar builds I've seen (with both USDM 10:1 and JDM/EUDM 10.5:1 engines). Ive seen several within 140-150whp dynojet numbers. Even if dynojet "reads high" I would be expecting 130whp for this car at the minimum. Just adding a megasquirt I would expect AT LEAST a 7-10whp increase based on timing increases alone.

Post a log with a wot pull. A good intake should get you near or at 100 kpa.

This intake shows the same values at WOT than the stock plastic tube with just the filter at the end (no maf), lowest I see is ~98.5-99 kPa at redline, at 80F ambient and few hundred feet above sea level.

This is one of the logs for when I did a Virtualdyno test about a month ago, showing ~140whp (with about 2 more degrees of VVT advance at redline than im running now):

https://cimg1.ibsrv.net/gimg/www.mia...68f3d6efc4.png

Crap header, stock cat. You are expecting fully optimized numbers from a setup which is not fully optimized.

Thanks, I decided to post here to get even more feedback, I might have been overlooking something or my tune might be garbage.
I am very surprised just the header and cat could produce such an insane power drop.

I will update the thread when I replace the header and add a test pipe until I can get my hands on a 200-300cel cat, and after the compression test.

Don't be.

Status update.

Went all out to rule out the exhaust. Now running RB header + RB resonated race midpipe (no cat). Same straight through 2.5" Muffler.
Re-did the intake tube in aluminium just to get the appropriate length to get rid of the 3500rpm torque dip

Dyno run (compared to old one):

https://cimg8.ibsrv.net/gimg/www.mia...c7612943f7.png

~10 bhp gain.
As you can see the intake now has the correct length and the torque dip is gone.

The only explanation for this I have is the low-ish compression.

How do you know its the correct length? did you dyno tune different lengths to find the best one for your car? An inch off is noticeable whp/wtq difference.

Imagine if you spent that 2000 dollars on a budget turbo setup instead of na mods...

This has been documented extensively over the years, there seems to be a magical number of 21" as the minimum, this one is >23" without the filter.
Its weird that you would even bother posting since you even commented on a thread with this very info last year
Intake length effects on torque dip are extensively documented on this forum and others for many years with further evidence that it barely has any effect elsewhere. In this case the tube diameter is the same and so is the elbow radius.

Your post was useless, it didn't further the thread topic, derailed it by questioning established knowledge and wasted everyone's time.

IMAGINE IF YOU SPENT HALF THE TIME ACTUALLY LEARNING THINGS THAT YOU SPEND POSTING GARBAGE ADVICE AND NEGATIVE COMMENTS NON-STOP





Just imagine

How is that negative? He's spending thousands of dollars trying to make more hp, when there are quality budget turbo options out there. (MKturbo and Kraken)

I figured this was a safe post to make, seeing this is miataturbo.net? Im honestly really confused.

This dude has a legit thread, with dyno plots, testing, numbers, and generally worthwhile content. You're crapping it up for no reason. Stahp