When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi guys,
First of all, I would like to appologize for my lack of care to fix picture-sizes in the pics below.. i hope you will survive!
I thought i would share a little about/from my build.. (i'm sorry for some broken spellings and whatnots)
Background:
I started beefing up the cooling and week parts of my 1998 1.8 NB miata in the late winter 2018-2019/early spring 2019. Mishimoto radiator and dual fan setup, a mishimoto oilcooler with a thermostat. I changed to a stage 2 competition clutch with a 7-8lbs steel flywheel.
So #1 setup with some "external mods" (still now running on stock engine) was putting down 167whp @8000rpm. It drew som oil at that high rev so i lowered rev limiter to 7500 and then everything was good.
Some kind of parts list:
Mishimoto alu cooler with fan shroud for two fans
Mishimoto oilcooler with thermostat
Skunk2 ultra intake and a skunk TB (which might be to big for my low power output)
700cc Denso injectors
Noname 250LPH fuelpump (probably China)
Fab9 COP-setup
Qmax coolant reroute kit
CC stage2 clutch and light flywheel
Miataspeed engine mounts
IRP shortshifter
OEM Snapon hub and a noname steering wheel in suade
Snubby mid console
OEM seats with foamectomy
Racing beat 4-1 header (same lengths) and a 2.5" stainless exhaust with end can from mx5parts.co.uk
Ms2PNP running E85
At this point i had bought a used JRSC-kit with an m45 SC that was laying on the work bench staring at me. I didn't even go through the whole first seasong with new setup until i started to work on mounting that kit. The car was running great so i was a little hesitent..
In the N/A setup, I found 150whp streettuning but the dynotuner found another 17whp which was very nice! (this chart shows purple with N/A setup and blue with the later added SC@0.27bar/~4psi):
Second setup was as you probably figure, a SC-setup. I ran it first without intercooler, then changed pulley and saw the MAT which emediatly made me mount my ebay-kit frontmount IC.
After this second tuning/dyno-session i got bitten by the boost bug.. so started sourcing other pulleys for more and more boost..
In the end of the season i was running 130/62.5 only in pulleys..
you know what.. i will not write a novell here all at ones.. i will upload my build-pictures so you can see for yourself..
Currently i am running:
m45 supercharger with 150/62.5 gearing (lowered the rev limit to 6500rpm)
A lowmount Kraken cast manifold and 3" stainless exhaust with a magnaflow end can
A Garret GT2871R .86 turbo
Supercharger is feeding turbo, and is bypassed by pressure trigured level at 0.39bar ~5.7psi. (with an actuator from a m90 feed by a standalone boost controller/MAC)
I use two MAC-valves.. one is controlled by a standalone controller to open the SC bypass on given pressure, the other one is hooked up to the MS2-box to control the turbo boost.
Turbo is then feeding a frontmount intercooler.
Additional mods as before:
700cc denso injectors running e85 (about 50-60% duty if i remember correctly)
250lph fuelpump
light flywheel and "heavy" duty clutch ..
ms2pnp
Current dynosheet (and keep in mind there is a lot of tweaking to be done, but car feels completely bonkers), blue line is with only supercharger and turbo being passive.. purple is with sc and active turbo.. controlled with a toggle switch in the cockpit.
Here are some random build-pictures from the journey: T28R from a SR20DET to the left and the new garret gt2871r i ended up running to the right. Testing out fitment..
One of my goals to keep true to in building on this project car is to use prefab parts, and fabricate as little as possible to save time on sorting out what works and what does not.. for me time is more valuable than keeping a low budget.
I have done minor modifications to adapt parts.. added a barb here and there and cut the lengths of pipes/hoses and such.. other than that it is strictly a composition of bolton parts.
Welcome! Good to see another outside-the-box project that made it passed the sniffing-butt phase.
Awesome!..
I had a minor setback with my turbo today.. the impeller seems to be stuck.. but i guess it's one of the two.. either the lump of meat holding the wrench (me) f*cked it up.. mounting.. (but still with purchase parts including oil feed lines and everything) or this turbo was at fault from the get go..
Either way.. now to troubleshoot and then call the turbo supplier for some discussions on how to get a turbo in the car again..
Everything cannot be success all the time so why not a little bit of challenges..
This expired token thing on this forum drives me crazy..
Here i go again..
Tore down turbo setup today, did some tests.. found the culprit.. it was thread tape leftovers that was stuck in the hole from the plug i used and put there 1,5 years ago.. tomorrow i will talk with the turbo shop about what to do next..
here.. pictures..
Ouch! Well at least you have found the problem. Perhaps this was also causing the late spool on the turbo.
Well.. yes.. maybe.. but also maybe not.. since i don't get full boost from sc until 2500 rpm's or so and i still get very little boost from the sc.. i am really not having that much help from the sc.. since it only helps before spool starts and not so much after (after it starts the turbo is starting to be fed like normal/expected amount of exhaust.. ) .. it lowers the threashold but maybe not speeding up the spool so much.. and this turbo is supposedly expected to spool around 3750-4000rpm on this engine it doesn't have that many rpm's to come early ..
Now i will see what they say.. i don't think they will be able to restore/fix it.. perhaps to much damage to things.. and if it is so.. i will try to order a gtx2860r instead.. to broaden my torque-curve a little like i intended to do from the beginning..
An 0.86 AR hotside 2871 will not spool below 4k on a 1.8. At 5280 ft altitude an 0.86 ar hotside gtx2867R spools at 5000-5200. A 0.64 is around 4500. At sea level these numbers will reduce by ~12-15%.
An 0.86 AR hotside 2871 will not spool below 4k on a 1.8. At 5280 ft altitude an 0.86 ar hotside gtx2867R spools at 5000-5200. A 0.64 is around 4500. At sea level these numbers will reduce by ~12-15%.
So that means we actually did see a spool threashold improvement due to the sc.. because my 2871 .86 did start spooling around 3300 or so on high gears..
There certainly should be.
The supercharger creates more exhaust flow, and the turbo helps fill the blower rotors.
They should help each other, and pressure ratios multiply not add.
It may require a smaller turbine housing, and/or a smaller supercharger pulley, but both are fairly easy to change.
Yeah, at 5-6 psi I would expect the spool to go down ~30% for a turbo not riding the compressor surge line.
It might be so, that the threashold was helped and the lack of oil and consequenzes of it hurt spool in the end.. but to be honest i don't know much about where the surge line goes.. that might have hurt the turbo aswell in this.. although running dry was definately the main issue in this failure..
Originally Posted by Warpspeed
There certainly should be.
The supercharger creates more exhaust flow, and the turbo helps fill the blower rotors.
They should help each other, and pressure ratios multiply not add.
It may require a smaller turbine housing, and/or a smaller supercharger pulley, but both are fairly easy to change.
Well.. i think in this case it only gives more exhaust flow before the turbo starts to build boost and the pressure between sc and turbo is above atmospheric.. after that it doesn't produce more boost or exhaust than with a single source setup (because the pressure drops quiet fast).. the exhaust amount is in straight relation with amount of total boost.. and as you could see in my dyno sheet the midpipe looses pressure really fast.. after that it doesn't multiply anymore.. the m45 is not really a big blower in this .. but it helps alot in low rev range.. (actually i thought it did alot in the whole rev range but just lacking on top and noticed when pulling side by side with other turbo cars).. bit by the boost bug i had to have "a little bit more.. and a little bit more.. ".. yeah.. you know the story
Of course, please correct me if i am wrong!.. i am really just a novice in this field.. !
Unfortunately, with a super-turbo, I don't think you get a compound effect. Increasing the PR across the turbo decreases the PR across the SC. That said, you are correct, the SC does provide a pseudo displacement multiplier from an exhaust energy perspective.
The SC is still a win, and you are not limited to a lower total PR by the SC like you would be with a compounding turbo-super.
Unfortunately, with a super-turbo, I don't think you get a compound effect. Increasing the PR across the turbo decreases the PR across the SC. That said, you are correct, the SC does provide a pseudo displacement multiplier from an exhaust energy perspective.
The SC is still a win, and you are not limited to a lower total PR by the SC like you would be with a compounding turbo-super.
When i think about this i gain what i aim to gain.. i get less feeling of "lag" in low rev range.. and i get less parasitic loss than at the higher rev range because the sc is bypassed.. although it does give more loss than a turbo it is a very good compromise and more power can go to the wheels.. which is good at least until something breaks.. hehe.. but i am trying to learn from you guys with the aim to keep at tops 220wtq (298WNm).. but to perhaps keep the torque there as much as possible.. the absolute optimal setup for a stock engine (i'm guessing based on this experience) would be just a clean mp62-setup and then you are there..
Twincharged is more exciting though.. and challenging.. and odd
I intentionally ride the surge line, it is why I run an 0.64 hotside and what makes the gtx2867r gen 2 a fantastic turbo for my application.
How much power output do you get?. what i read about the gtx2860r gen2 is that it supposedly flows enough for 475hp.. which is alot!.. what do you gain from having a bigger compressor ? (i understand that would be the difference between 60 and 67?)
I have built several of these turbo/blower compound systems over the years, and as Ted says, the supercharger multiplies engine capacity as far as the turbo goes.
The turbo does not "know" the engine is supercharged, it just sees flow. So if you add a supercharger run at a drive ratio that provides for example a 1.5 density ratio, a 1.86 Litre engine looks like a 2.79 Litre engine to the turbo. Now maybe a 2.79 Litre engine (or whatever it works out to be) is still not big enough to spool the turbine you have.
So you get two choices, drive the blower faster, or reduce the turbine A/R. The whole thing needs to build up enough flow to the point where the turbo can begin to work, otherwise not much is going to happen.
It certainly does compound, and spectacularly so. The most noticeable effect is how rapid boost can build, especially in the lower gears, and the absence of lag.
I have built several of these tubo/blower compound systems over the years, and as Ted says, the supercharger multiplies engine capacity as far as the turbo goes.
The turbo does not "know" the engine is supercharged, it just sees flow. So if you add a supercharger run at a drive ratio that provides for instance a 1.5 density ratio, a 1.86 Litre engine looks like a 2.79 Litre engine to the turbo. Now maybe a 2.79 Litre engine (or whatever it works out to be) is still not big enough to spool the turbine you have.
So you get two choices, drive the blower faster, or reduce the turbine A/R. The whole thing needs to build up enough flow to the point where the turbo can begin to work, otherwise not much is going to happen.
This is my conclusion also, which is why i will change to a smaller turbo i think.. the supercharger is already at a 150/62.5 pulley setup and to not grenade it i lowered the rev limiter to 6500 (which is still overspinning it.. just not so much.. )
07-19-2020, 05:48 AM
Twincharged NB Miata
3
