My way-over-budget...budget build thread - 99 Turbo
 

Well, after a year and a half of wrenching, my 1999 Miata build is nearly done. In an attempt to give back to the forum, here's a rundown of the build and a brief pictorial.

The project was NOT intended to be a big dollar/big HP build and ended up being much more costly than expected (doesn't it always); had i known where it was all headed, I would have chosen a few things differently. For example, higher comp pistons, better flowing turbo/exhaust setup, etc. That said, and all things consider, I'm please with the current results and the things I've learned throughout the process. There's more tuning to be done for sure, but I'm still learning that as well.

Enjoy!


Engine Internals / Accessories:
- Manley 14011-4 H-Beam Connecting Rod Set
- Weisco Pistons K553M835 (0.02 over / 8.4 comp ratio)
- ARP Main Stud Kit (218-5401) and Head Studs (2184701)
- Boundary Engineering Oil Pump Stage 1
- SuperMiata Harmonic Damper

Head:
- Sealed Power VS855 Valve Springs
- Supertech Valve Seals Miata

Engine Control / Spark:
- LS2 Coil-On-Plug
- Supermiata Trigger Wheel 36-2
- MegaSquirtPNP G2
- BKR7EIX
- Speed Density setup

Fuel:
- Injector Dynamics Fuel 1050X injectors
- Deatschwerks dw300 (hard wired)

Turbo/Exhaust:
- ebay GT35R (Stage III Ceramic Ball Bearing T04E GT35 Spec T3 5 Bolt .70 .63 AR)
- ebay T3 log Manifold
- Precision Turbo PTE PW39 39MM External Wastegate (dumps directly next to trans)
- Customer turbo elbow
- Flyin Miata Turbo Downpipe (Lower Section) w/ 2.5 boost actuated dump
- Flyin Miata 2.5" Resonated Turbo MidPipe with Milspec 3" 100 cell Catalytic Converter
- 2.5" 63mm Exhaust Control Valve Set boost Actuator CLOSED Style Stainless Steel

Intercooler/Cooling:
- KOYO V-Core Radiator
- ebay 29x9X3.0 intercooler
- ebay universal 2.5inch intercooler tubing kit
- ebay universal SQV Blow Off Valve
- Rival Autosport Type 1 Universal Aluminum Hood Louver

Transmission/Clutch:
- 6 Speed Swap
- Shifter Rebuild Kit (5xRacing)
- Flyin Miata Happy Meal Clutch (Level 1)
- Flyin Miata 10.3 lb flywheel
- Stainless Steel Braided Clutch line

Drivetrain / Body:
- 3.9 Torsen Swap
- FC RX7 Rear end Housing
- Delrin Rear Differential Bushing
- Delrin Door Bushing
- Mazda Competition Motor Mount

Suspension/Wheels:
- Flyin Miata V-MAXX Classic Coilover
- Flyin Miata Front and rear sway bars (1.0" front and 0.625" rear)
- Flyin Miata Frame Rails Reinforcement Kit
- 15x8 Jongbloed w/ Toyo 225 R1Rs

Other:
- Jeggs oil catch
- Innovate LC-2 Digital Wideband
- 5X Racing Miata Oil Pressure and Water Temp Gauge Kits
- huge amount of OEM seals, gaskets, nuts, bolts, bla bla bla

And thanks to everyone who's posted helpful content on the forum. Without it, this project would not have been possible.
Special thanks, in no particular order:
- Reverant
- Braineack
- 18psi
- Savington
- stefanst
- patsmx5
- thecarpassionchannel (youtube)


----------------------------------------

June 2016 - With just under 98k miles, the car arrives home. It was intended as a casual toy to putts around in on the weekends.
https://cimg6.ibsrv.net/gimg/www.mia...134496c725.jpg

In under a week of ownership, wheels and roll bar arrived. A month or so later, I started ordering the FM suspension parts mentioned above.

https://cimg7.ibsrv.net/gimg/www.mia...e50fe881fd.jpg
https://cimg8.ibsrv.net/gimg/www.mia...f28199bc79.jpg



November 2015 - After driving the car for about 5 months, I noticed the oil pressure gauge flutter. Long story short, I apparently had a small oil leak that i didn't catch in time. The somewhat noisy rod bearings only became worse at this point. Since the winter was about to set in, i decided to pull the motor. This being my first deep dive into an engine of any sort, it was nerve racking.


https://cimg9.ibsrv.net/gimg/www.mia...2aaf1b358a.jpg
https://cimg0.ibsrv.net/gimg/www.mia...2970edc1a1.jpg


Gross
https://cimg1.ibsrv.net/gimg/www.mia...f85f0ef079.jpg

Here's a comical attempt at trying to hold the crank bolt in place with some extra metal i had in the garage.


https://cimg2.ibsrv.net/gimg/www.mia...54bbd068a0.jpg


FAIL

https://cimg5.ibsrv.net/gimg/www.mia...217d23508c.jpg

January 2016 - Picked up the block from the machine shop.

https://cimg7.ibsrv.net/gimg/www.mia...376a7ec723.jpg

Engine parts also began arriving

https://cimg6.ibsrv.net/gimg/www.mia...3f3289746c.jpg

February 2016

https://cimg8.ibsrv.net/gimg/www.mia...b912d974d8.jpg

March 2016 - disassembling the head on the living room floor.

https://cimg9.ibsrv.net/gimg/www.mia...923839467a.jpg

May 2016 - The engine is slowly coming together.

https://cimg0.ibsrv.net/gimg/www.mia...db67d559cb.jpg

June 2016 - Head back on the block. Turbo mounted

https://cimg1.ibsrv.net/gimg/www.mia...3788703eed.jpg

Additional Items on (please ignore that stupid turbo head shield)

https://cimg2.ibsrv.net/gimg/www.mia...6b212828b7.jpg

Cat helping

https://cimg3.ibsrv.net/gimg/www.mia...12d666e9e5.jpg

July 2016 - It's back in the car!

https://cimg4.ibsrv.net/gimg/www.mia...6fdce0cc82.jpg

My cat providing direction on intercooler piping routing

https://cimg5.ibsrv.net/gimg/www.mia...a241b2e407.jpg

August 2016 - Finishing up the interior wiring (with additional guidance)

https://cimg6.ibsrv.net/gimg/www.mia...38b6823ff4.jpg

September 2016 - It runs! For the next few months I worked on getting the tune "correct" and adding other parts. Most of the time the car just sat in the garage due to crappy weather.

https://cimg7.ibsrv.net/gimg/www.mia...fd6203952f.jpg

May 2017 - Swapped the rear end to a 3.9. The 6 speed combined with the stock 4.3 open rear was a nightmare.

https://cimg8.ibsrv.net/gimg/www.mia...080ff2c6dd.jpg

May 2016 - The final product (for now):
https://cimg9.ibsrv.net/gimg/www.mia...2dc0909a82.jpg



Edit: Removed VD dyno graph and log. I suspect the hp numbers were a bit inflated.

Thanks!

Oh. That's what my car would actually look like if the paint wasn't shiet and it didn't have dings everywhere...

Awesome build. Hopefully I get to see it in person while I'm around town.

I'm guessing you bought stefanst's kosei's?

Congrats on getting everything running. Are you planning on doing the coolant reroute soon?

Just for lolz, you spool about as well as a s2000 making 800whp.

Best of luck with your build mate :likecat:

Thanks! I got the kosei's from tire rack. Probably won't do the reroute unless the car sees sustained track time.

Lol. Right? It recently dawned on me that I haven't touched the waste gate preload. I'll be messing with that today. I have a strong inclination it's set way too soft. Fingers crossed it helps!

You may want to reconsider the reroute.

The track time line of thinking is more for NA cars. FI introduces a whole new level of heat/hurt.

Especially if you still have AC installed, the condenser has an impact on airflow. One data point (of many) in a recent build thread: https://www.miataturbo.net/build-thr...t-90646/page2/ No track work, just interstate cruise.

Interesting. I'll strongly reconsider it. Let me do some reading.

Side note: shortening the wastegate arm actually hurt spool/power :vash: :facepalm:

A vendor here sells them. I really need to install mine. I've been lucky so far with driving temps. I'm still running lulz power (170ish rwhp) so it's a wash, but it'll need to go on rull soon since I have AC as well.

Here's the link: https://www.miataturbo.net/miata-par...r-mount-88962/

With your hot side the spool doesn't surprise me.

Don't listen to RTC, he makes less power = less superior. But I VD at 84whp so don't listen to me either.

Your cat is adorable

:(

When did you start making more power!?

I am sorry RTC. It was the binge rum drinking after finals talking.

Haha, thanks. He's an odd ball and friendly nearly to a fault lol

Attachment 180842

Update:
I ordered a new (better fitting internal wastegate actuator). It includes a few springs including a 1.5 bar that I plan on installing.

That said, i don't think it's going help. I found that:

• When completely CLOSING my boost controller, the wastegate still opens at ~22psi (intake pressure). That's with standard preload on a 14psi spring that came with the current actuator.
• This means back pressure in my turbo/exhaust must be so high that it's overcoming the spring, opening the flapper, and bleeding off boost - even without boost pressure assisting to press on the spring down.
• Thus, I think one of my biggest issues at the moment is too restrictive of a post-turbo exhaust (the ebay turbo elbow, the 2.5 inch piping, and the inclusion of a catalytic converter).

I plan to see if the new wastegate and stiffer spring has any effect. Otherwise I may be looking into other exhaust options. Outside of Begi and Flyin miata, any reasonably priced turbo elbows out there?

Update:

• The new wastegate (with a 1.5bar/22psi spring) did nothing for spool or power.
• I found an exhaust leak (pre-turbo) that I'll be fixing this weekend.
• I orded a Flyin' Miata cast log manifold to replace my current eBay one.

Bonus: Anyone want to guess why my tunerstudio logs won't capture a psi reading greater than 22.9psi? I'm pretty sure my map sensor is the standard 2.5bar mpx4250.

Because 14.7 barometric pressure + 22.9 psi boost == 37.6 psi absolute, which is 259 kpa. You're probably a thousand feet above sea level to get it that high. :)

--Ian

I'm at about 250ft :-/

https://cimg3.ibsrv.net/gimg/www.mia...509d59b349.jpg
Came across this on the underside of the intake manifold. Certainly not helping spool. :vash:

I'll be interested to see how much difference a single unplugged intake port makes with performance (though remedying the exhaust leak should also help).

Ohhh hayyyyyy.

Looking forward to the next VD pull result!

IIRC that's the one that feeds the VICS port -- if so, then it'll make a much bigger difference than just the vacuum leak.

--Ian

Yup! That port fed the VICS. Unfortunately, after reconnecting it and fixing the (small) exhaust manifold leak, the car only made marginally more power.

I did some more investigating and it looks like your guess was spot on: the MPX4250 2.5 bar map sensor is only "Good for 21-22psi of boost"
I'm considering picking up a MapDaddy 4 bar sensor, but I'm concerned about being able to remove the MPX4250 without damaging the board. Is this something that's even possible within reason?

Alternatively, I'm also considering just replacing the twisted motion gt2871 knockoff with a genuine Garrett gt2560r or gt2860r, but i'd hate to throw more money at this and only end up with 5 more peak hp. Right now it's taking all of 21 psi to crack 250hp. :-\

I'm also tempted to disconnect the exhaust pre-cat to see if the flyin' miata HF cat is hurting performance, but i'm not hopeful.

That said, i've been playing with timing, fuel and boost quite a bit, and only boost seems to affect power above 5K. Bringing up the timing, hearing knock, and then backing it back down, seems to have little impact on hp. (all as per VD). :vash:

Well damn. This explains a lot. Cam timing is off. :facepalm: https://cimg2.ibsrv.net/gimg/www.mia...34f584c21b.jpg

If it's a ceramic core FM cat, then the answer is yes.

As far as the MAP sensor goes, generally when reworking boards to remove components you have the choice of saving the board or saving the component. So yes, it's possible to remove the on-board MAP sensor without damaging the board, if you have a decent amount of skill in doing solder rework. I'm guessing you don't. :) (I'm not confident I could do it properly, either).

I like the off-board GM 3 bar MAP sensor from DIY. With that the on-board sensor can become a separate baro sensor.

But yeah, stupid cam timing is stupid. :)

--Ian

Map Sensor:
Great info! A "decent amount of skill in doing solder rework" is something i certainly don't have. It looks like this is the "off-board GM 3 bar MAP sensor" you mentioned is the way to go. I'm going to order it in case I decide to push more boost through the system - that said, I'm not 100% sure that's my plan forward.

I currently have peak boost sitting just over 22psi to avoid overrunning the current MPX4250.

Cat:
I'm running the 300 cell ceramic cat that comes in FM's 2.5 turbo midpipe. You feel this is restrictive huh? Good to know, but i may still just live with it....b/c environment :hs:

General Update:
With the cam gears correct, the tacotaco manifold replaced with a FM cast manifold, and seemingly no boost leaks, here's a Virtual Dyno readout on the smoothest road i can find in my area.

• It's currently running a very similar ignition map to Flyin' Miata's hydra map. There's NO knock with this map (the ONE exception, I can hear one count of knock in 5th gear at 6K RPMs ONLY if I'm running the car hard through 4th and into 5th).

https://cimg6.ibsrv.net/gimg/www.mia...e7ce7c8a7a.jpg
https://cimg8.ibsrv.net/gimg/www.mia...2528f16afc.png


Strange Voltage on Datalog:
As you can see in the screen shot about, my Voltage is showing >17. I can't explain this and need to look into it.

Next Steps:
I'm torn between: 1. Spend the time/money on dyno time to try and get the car dialed in better myself. 2. Replacing parts to unlock more potential (e.g. bigger/authentic Garrett turbo, different cat, etc). 3. Finding a reputable MS tuner familiar with Miata's and have them finish the tune. (Or some combination of the three).

In any event, i'll likely bring it to the track next week and to see what mph it can trap.

Update:

• 3 bar GM map sensor installed
• eBay GT2871 (a/r 64) removed
• Garrett GTX2867R (a/r 86) to be delivered by end of week. :)

Also did some exhaust testing. Fully removing my muffler (axle back) and it made no difference in performance (according to VD). So if there are any exhaust restrictions, it's not that. The exhaust is now 2.5" all the way through (though I'm still running a FM cat). More to come.

FWIW, I have a 2.5 FM exhaust setup with a Cat.

I think I just hit 200ish HP and that was at about 10-12 PSI. This is on what is the equivalent of a 2560.

Hmmm, interesting. That sounds roughly around where I'm at with the same psi.

At this point I should have the new turbo on by Sunday. If the car is still down on power relative to PSI, I'll pull the cat off - though I don't have high expectations with removing the cat.

If the cat and the turbo are still not effective, I'll be taking the head and revisiting the valves. More to come.

I'd like to see at least 270whp with 20psi based on my other variables.

Virtual dyno with no retuning isn't necessarily the best way to check for exhaust restrictions, because there's too much noise in the signal. A better method is this: run VEAL a few times to get the fueling dialed in, then turn off EGO correction. Do a few low-RPM to redline pulls in 3rd using the same piece of road and datalogging them. Change exhaust, then repeat the pulls and compare the logs. A freer-flowing exhaust will manifest as quicker spool, a leaner air/fuel ratio, and will also affect the boost. If you're running open loop EBC you'll get higher boost, if closed loop then you'll get lower duty cycle for same boost. (mechanical wastegate will also have lower duty cycle, but since it's mechanical it's not logged so you can't tell).

The best way of doing it, though, is to actually instrument the backpressure and monitor it. To do this, you need a pressure sensor from mouser, similar to the one used inside the ECU as a MAP sensor, and you need a way to hook it to the exhaust. I've done this by getting an O2 sensor bung plug, drilling a hole in it, tapping that hole for 1/8 NPT, then getting a 1/8 NPT compression fitting from the hardware store and a coil of copper tubing. Use that to go 4 or 5 feet from the exhaust and by that point it will have cooled down to the point that you can stick a rubber or silicone vacuum line onto it. Run that to the pressure sensor, then wire the sensor to a spare analog input on the ECU and datalog that value. You can then do pulls and actually measure the backpressure in the system. If you've got a tapped hole in the exhaust manifold for an EGT probe, then you can pop that out temporarily and add the sensor there too, to get exhaust manifold pressure.

When I did this on my car, I discovered that the "high flow" cat that I had was a much greater restriction than advertised. Swapping it out picked up over 40 hp on the dyno (with retuning).

--Ian

Thanks Ian!
I should have been more clear: When i removed the axle back, I did some fuel optimization (via VEAL) and took multiple pulls on a (nearly) flat road from <3K to read line. (I did NOT turn off EGO correction though).
If there was some change in spool or performance, it was canceled out by noise/other variables. I'm not saying the axle back ISN'T a restriction, but it's certainly doesn't seem to be the biggest one currently in my setup. In other words, it could become an issue after i remove the cat, for example.

Regarding back pressure monitoring, I totally agree. If some of the easier solutions don't pan out, I'm definitely going to exactly what you outlined above.

In the meantime, here's the new genuine GTX2867R next to the Twisted Motion (eBay) GT2871.

Interesting development:
The GT2871 from eBay was advertised as an .64A/R turbine housing. I found a ".86A/R" embossed on the housing today.
THUS! I have a hunch this GTX2867R is going to make nearly the exact same HP/PSI i'm currently at! :vash:

https://cimg9.ibsrv.net/gimg/www.mia...734c36fefc.jpg

So 20 lbs of boost is 270 hp huh?

I'm pretty sure that the 2560 runs out of steam around 15-16psi and makes more heat than anything else past that, but I've seen dynos of it (JasonSBB?) at about 270hp. And he had a 2.5 exhaust at the time afaik.

I think Vlad (18psi) does some road tuning. Maybe talk to him as a first step? I think his prices are pretty reasonable and it might be helpful to have him run through your tune to see if anything jumps out at him. I think PatMX5 does this as well. Worth a shot before you throw more money at parts...given that the limiting factor here is your understanding of tuning ish, right?

Well, 22+ lbs on a ebay GT2871 is ~ 270whp. :-\ But again, that's with 8.4:1 pistons and the FM cat (all through the 2.5" exhaust).
I'm really hoping that the eBay turbo was greatly holding me back, but i'm not optimistic (especially if the ebay turbo had a .86 turbo housing and not the .64 advertised). :dunno:

If the new turbo + dropping the cat doesn't EASILY make over 300whp at <24psi, I WAS going to pull the head; it's the only item left in the system that could be greatly holding me back.

All that said, thank you very much for mentioning Vlad and PatMX5! I'll certainly be reaching out to them if things don't greatly improve with the turbo swap. I probably should have already :).

Read this if you're bored and want to see folks muse about just about everything.

https://www.miataturbo.net/dynos-tim...-272-hp-60479/

Well, without touching ANYTHING except fuel and boost, here's a ROUGH comparison between the Twisted Motion (ebay) GT2871, and the Garrett GTX2867R.
As you can see, the GTX blows the eBay turbo away with efficiency, making 30+whp with 3+ (15%) less psi! (Obviously the car became very rich up top).
Much more tuning to come this weekend, but I'm very happy with the rough/preliminary drive.

https://cimg5.ibsrv.net/gimg/www.mia...3ad5d8b440.jpg

This is likely the cleanest/flattest pull yet. Power is ok I guess. I'll likely be bringing the car to the track tonight to see what MPH it turns (weather permitting).

https://cimg7.ibsrv.net/gimg/www.mia...038f64f815.jpg
https://cimg8.ibsrv.net/gimg/www.mia...6df19450e1.png

Are you using ebc?

No. I'm using a super cheap DIY manual one.

Anyone want to play: guess my trap speed?

I'm just kind of lost as to why your spool is so seemingly slow. Though that might just be the bigger turbo. My tune isn't great and I'm making more torque than you till a bit past 4k. That's on a JB 2560

What fuel are you using? 93?

I guess 120mph

118.69mph

109.65mpg :ugh: Running standard 93 pump.

I think I'm losing a lot in the back half. For example, I was running 10+mph faster than a stock/new WRX in the 8th, and by the end of the 1/4, i was still only about 10mph faster than him.
I had a best of 89mph in the 1/8th which could/should have put me around 112 in 1/4.

ridethecliche has me wondering if my $20 Amazon boost controller has anything to do with it.
I may also be swapping out my upper down pipe (i.e. turbo exhaust elbow) but I doubt that'll do much and going with a smaller A/R exhaust on the turbo. We'll see though.

Something's definitely not right. Here's part of a log from the 109mph pass. With each gear change, the car drops boost down to <5PSI, and then takes 1K rpm to recover back to peak boost. That doesn't seem right?


My waste gate flapper may be getting stuck against the inside of the upper section of the down pipe. I've tested this and know it COULD happen, but I didn't think it was opening enough to actually cause it. Taking it apart as we speak.

https://cimg8.ibsrv.net/gimg/www.mia...c67a646297.png

What's wastegate for you?

This is something I was told to do to test spool:

-set boost cutoff at a level just around what you're tuned for. Mine was set to 12. You can also be more conservative here and go a few psi below that because you want to see ramp up.
-disconnect vac tubing to the wg.
-do a pull in 1:1 gear starting at 2k.
-let off when your boost cutoff kicks in

This shows your best case spool scenario. If you're way under this, then it shows that things aren't optimized. Obviously I'd only did this once or twice and only if your shit is working by testing at a lower cutoff with everything plumped properly first. Danger to manifold! But it gives a best case scenario you know? A benchmark of sorts.

I posted a few logs on my thread recently.

Also EBC!



​​

I'm running a 1.5 bar (21.7psi) wastegate spring.

What you're proposing makes sense. And just so I'm clear, it would confirm there:

• Is not an issue with the the wastegate opening early/staying stuck open, correct? It would not be proving anything boost leak related.

Yeah, I don't think it would show anything leak detected. You have to listen and use a boost leak tester for that. It just shows you a theoretical max spool speed since the wg never really opens.

I'd wait for a senior member to chime in before doing the above though. I know why this works and think I'm correct but id rather have someone agree with me first lol. This isn't the best thing for your turbo, which is why it needs to be done once and done right. I did it 2-3 times on the same strip to make sure I had good data. But it's definitely a thing where you get to where you test, stop, disconnect, run test, then stop to check the log and see if it's good and reconnect if it is.

I'm not sure how much it helps with an mbc, but it basically showed me the theoretical max I can get with ebc tuning. I found out I had far more work left to do than I anticipated!

Do you hear anything that sounds like a leak when you pop the good while idling? I know my BOV leaks. I know colipto just went through and chased down and fixed a lot of leaks on his setup and the bov was one of those spots leaking.

That's partially why his spool is slow.

I'm 100% confident I have no leaks BETWEEN the turbo outlet, and the throttle body (which obviously includes the BOV). I made a boost leak tester and that entire section can hold 30+psi for minutes on end. I wonder if my BOV is set too tightly, not opening long enough, and is stalling the turbo between gears.

In any event, I ordered a flyin' miata upper downpipe section (turbo exhaust elbow). This will stop the wastegate flapper from interfering with my current turbo exhaust elbow (and possibly getting wedged open), though I'm still not convinced this is my issue.
I guess I should also order a quality boost controller as well....b/c at this point, why not :facepalm: (ffs)

I'm also actively going to try and trade my A/R .86 for an A/R .64.

Try what I said too. The mbc is out of the equation at that point.

What's the highest wastegate pressure you can run? If you can reach that faster without the mbc, well then you've found your holdup!

Thanks for the tips!

Remember the boost leak i was 100% sure i didn't have? Well.... turns out I had a slightly deformed intercooler pipe that was causing the coupling to leak only if the band clamp was clocked a certain way.
In addition to fixing that, I replaced my homedepot boost controller with a Hallman Pro (extreme waste of money in my opinion), and my eBay turbo elbow (upper down pipe) with a Flyin Miata cast unit (again, a waste of money considering my issue was a boost leak).

Spark notes: Spent nearly $400 on replacing working parts, trying chasing a boost leak :facepalm:

The car should be together by Tuesday night and back to the track by Friday. My arbitrary goal is to put down some solid hp numbers across the RPM range and trap 112mph.

How's it going? Any progress with the changes?

Mehh...I guess it's going ok.

I swapped the 2.5 inch / 300 cell / ceramic / megaflow cat (that comes on Flyin' Miata's 2.5" mid pipe), with a 3 inch / 100 cell / metallic / mil.spec cat.
Below is a VD comparison pull between the two cats (same stretch of road, both in 3rd gear). The blue line (old cat) was from the morning before going to the track mentioned earlier in the thread.

While it helped boost/spool a bit, overall power is still lackluster (compared to the imaginary numbers I've got in my head from reviewing other people's setups). The power flattens out so dramatically after 5K

I'm going to make one more road tuning session one night this week and see where I land. I'll then be either setting up a dyno session, requesting paid tuning help, or both i guess

https://cimg6.ibsrv.net/gimg/www.mia...725d89f097.jpg
https://cimg8.ibsrv.net/gimg/www.mia...eb6689737a.jpg

Talk to vladdddd

Though he might be overbooked at this point lol.

EBC is faster and better spooling than a spring, as big as it might be.

I'm curious about your eBay turbo. Looks like a T3 copy to me from the compressor wheel (size/fins)- completely different from your Garrett GTX2867R. Did you pull housings to measure the wheels and check fins/contours?
Here's an eBay t3 compressor on the left (next to a Garrett T4 compressor). The wheel sizes will make a bigger difference than AR. I narrowed down my poor spool to a housing swap- from a Garrett to eBay turbine housing (both stage 3 t3). Turned out that the turbine wheels (though same specs) had different contours. In my case the blade to housing gap was excessive at the turbine inducer.

I scanned the thread and dont' see it: what is OP using for boost control?

At the start of the thread, I was using a $20 diy special off Amazon. About a month ago, I upgraded to a Hallman Pro.

I thought you were only using a 20 psi spring. Anyways, ebc is also better than a manual :)

While true, the difference is nowhere near as drastic as many make it out to be.

Yeah, but there's about five strikes against this car showing good boost response. Too-big A/R, too-small exhaust, lousy cat (OK, one is fixed), no EBC, and pulls in 3rd instead of 5th.

--Ian

Let me attempt to grab a 5th gear pull tonight and report back