gearsoft

Haven't posted for a while so I thought I would give an update.

Just pulled the car into the garage and putting in the SC and the updated arduino/every/bluetooth, wiring and gauges. I'll post after the weekend to update on how it's running after the install.


New control box Still using the piggyback for fuel but this will control the SC, WMI, Bypass, look at WM pressure, air tank PSI, and passthrough info for oil temp and PSI and fuel PSI. It has bluetooth and an interface that will be in the car to make any adjustments and monitoring



Documented the wiring this time...



Using great app that's free from Bluetooth Electronics to make the interface.

Dilshan Liyanage

Hi any new updates? Any plans to put a intercooler

gearsoft

I had a few setbacks with my last rebuild. The housings that I had machined and re-nitrided wore out in 3K miles. So I bought a low mile motor and put my good parts in it. All good now. I have great compression (about 8.5 psi on all rotor sides) and it runs awesome as an NA.

That said, I am working on some mods to the supercharger. One is to add an intercooler, the other to to add a better bypass to run in NA mode when I'm just cruising the daily driver. I have a few pics of the ideas and will be starting on these soon. Any feedback is welcome, good or bad...


I'm going to be doing some cutting and welding on the SC manifolds so I threw together a hollow block using some spare cases I have so I can have a jig for the mods I'm planning and still keep everything lined-up


Cut off this part of the manifold and seal that side and then open the other side and weld it back on.


Same mod as this guy made to the manifold but I won't be using this size intercooler. I'll be moving my battery to the trunk to free up some space and run the intercooler tubes up to an air-to-air in the front.


For the bypass I'll cut off and move the section that deals with the fuel purge solenoid and the vacuum box and open the manifolds where indicated.


After that I'm planning to use a 'cutout' valve to control the bypass. It's a 2 1/2" bypass valve and should be plenty to run NA. I'll make the flanges with some aluminum plate I have and some aluminum tubing and connect one side with the blue intercooler hose and clamps. I'm open to suggestions here but I think this will work ok. I am a little concerned with the cheep cut valve I bought but I'll throw a tack weld on the bolts of the flap so they don't fall off in my intake and eat my engine.


Been doing a few projects welding aluminum like this rechargeable bluetooth speaker


This stuff is pretty easy to weld compared to the cast aluminum but I've also been doing some practice welds on some old aluminum cases and water pumps I have to make sure I don't totally destroy this SC manifold.

Dilshan Liyanage

Well i’m glad you have made some progress .From my side the situation in srilanka was not so good with the covid..we have just passed the peak and the life is not normal yet..i’m still waiting to do my custom intercooler work..


Glad to see you have great compression numbers..i think what you are going to do is correct concerning the intercooler side but i would think twice before cutting the purge solenoid part..for me i had no issues with N/A drivability with compressor off..yes it will free rotate.. but i don’t see a big power loss or anything with superchager off mode..my plan is to make a front mount intercooler setup.i will not add a bypass mode..not sure it will effect my N/A driverbilty..i like the idea of greaddy style intercooler set up..



What do you think about this idea?i just did a rough test and i think there is enough clearance for the lines..

Dilshan Liyanage

Finally, I was able to find the time to start this project.
As I said earlier, I wanted to go with the FMIC setup without the bypass. I went to a local custom silencer shop to do the velding part. Everything was done as per my instructions. I went with a Sard 600 x 300 x 65 x 2.5 intercooler size. (500x300 core) I decided to go with 2.5 inch pipes all the way and made a custom manifold for the supercharger outlet side. The battery was moved into the trunk.Everything went as per my liking.

After the first start, the car didn't stay idle after warming up, but it went away after a couple of cycles. It still stalls after high RPM pulls. I suspect small vacum leaks . I'm still using the Blitz controller box. I've noticed a very small lag when compared to the non-intercooled setup, and the drivability isn't as smooth as it used to be. I hope this can be addressed with a tune. Now the max boost I'm seeing is 38KPA (5.5 psi). I don't know the pressure loss due to the intecooler choice. Overall, I felt like the pull was a bit stronger compared to the non-intercooled setup.

Now the next challenge is finding a way to tune this, as I don't have any tuners locally. My plan is to remove the blitz system and power the superchager clutch directly with an off/on switch and tune it with a versatuner. I have noticed that even with the superchager off mode, the car runs OK.

My concern is the pressure drop. 5.5 psi, previously it went up to 8 psi. I'm not sure if my intercooler choice is correct or not, but I hope my gains are greater with intercooled air.
Overall, I'm happy with the setup.Soon, my intake airfilter will be relocated to the front as my old AEM filter is too big to fit inside the front bumper.

I am open to everyone's suggestions and ideas.

TeamRX8

iTrader: (25)

the before and after IAT difference will likely explain the before and after pressure difference
.

Dilshan Liyanage

Good point..my intake air temps were anyway bit high as my intake is still inside the engine bay. next mode is AFR gauge and the IAT senser to the intercooler outlet side..
i think the intercooler is doing a good job. more dense, has less pressure

jcbrx8

Couple of observations...

• First, looks like you were ingesting ambient air from the bumper area w/ the OEM air box originally, and now you're ingesting hot engine bay air. If that's correct... you're ingesting hotter air now..., then IC cooling it, i.e. 3 steps forward (IC), 1 step back (eng. bay air). Recommend you move the filter into the bumper area.
• Secondly, as you stated, you've introduced a new pressure drop across the IC, but the IC cooled air should more than overcome that.
• Finally, you've made significant changes. I suspect you'll recover your boost w/ a solid tune.

Edit:

• Also watch coolant temps w/ your 300mm (11.8") high IC. Those of us who've run a 12" FMIC have had issues keeping ECTs down d/t the IC obstructing rad airflow.

Good progress.

TeamRX8

iTrader: (25)

unlikely imo due to the SC being on a fixed pulley ratio rpm relationship which then firmly sets the flow output as opposed to a turbo with an adjustable flow/rpm relationship

it will likely take a pulley change to see any noticeable pressure change, that’s how SC’s work.

I get why you say/think that, but even though it’s ingesting hot engine bay air now it still has the IC to handle it along with the SC mechanical heating where before it more or less had nothing at all to alter IAT.
.

jcbrx8

I can understand your logic ...having referenced the direct belt driven relationship inherent to a SC design. Yes, a belt change is required to see significant boost increase, but he's currently reporting a 30% reduction in boost after installing an IC. As I stated IMV he should recover that 30% w/ good "sorting" and a tune. We'll see what happens...

TeamRX8

iTrader: (25)

you’re likely also overlooking the added piping length, elbows, coupler joints, and IC itself and the resulting dP increase that didn’t exist before.

Dilshan Liyanage

Thank you for all the inputs,
As mentioned soon i’ m going to relocate my air filter to the front bumper.

coolant temperature was never a issue so far as i’m from a tropical country all year average temp is around 30 degrees c.i think my cooling system is doing a good job(fal setup with a reamemiya radiator)

since this is a root style blower(ogura TX12)i dont think changing a pulley will make any pressure increase. max boost comes around 6000 rpm (8.5psi) and later it slowly drops.so i think i’m limited to max 8.5 psi.

anyone think changing my current intercooler size from 510*300*65 to smaller 550*180*65 will recover some boost pressure ?i’m going to swap intercooler and see if that makes any difference.

or maybe my intercooler is too restrictive and need to go for a bigger .. i’m bit puzzled

gearsoft

Hey Dilshan, Great accomplishment! I really like how you decided to go with the custom manifold for the supercharger outlet side. I've been hungup on this part for modifying mine. My plan was to cut and modify the original manifold but I've been nerves about doing this because welding aluminum is difficult and even more difficult being old and imbedded with oil and gas. Where did you have that done? can you have another one made or give me a contact that I can get a copy of the one you made? The setup you have does look very clean.

After seeing the issue you're dealing with the boost drop I started looking at alternate pulleys. Either for the alternator pulley that drives it (larger) or for the SC clutch pulley (smaller). Looking at AC compressor clutch assemblies that might fit so I'll let you know if I find something that fits and what ratio. Anyone on this thread know how to calculate the ratio difference needed to get from 5.5 psi back to 8.5 or 10?

My engine rebuild is really running great though. 120 psi hot on all rotor sides! So I've just been having fun driving this NA for now but I want to get back to the SC this summer and add the IC. I'm really glad you went ahead with this project though as I'll most likely just copy what you're doing except I'll also leave the water/meth setup I already have and work that into the arduino program and e-manage ultimate tune.

Dilshan Liyanage

Thank you,it was lot of work, i never wanted to cut the original manifold,so decided to make separate one. It was done in a small local silencer work shop in srilanka under my instructions.(made out if alloy) Maybe i can help you with that. i can make a same one and post it to you if you want.

Do you think tx12 can make more than 8.5 psi?since this is a small root style blower maximum boost comes at low rpm.let me know if this can make more psi increasing the alternator pully size. If so making a custom pulley is not a big deal in srilanka. I can help with you that also


Okay for pressure drop issue i’m thinking to go for 2inch pipe on hot side and keep the same 2.5 pipe cold side and going to try a slightly small intercooler core. 21*8*2.5.. let’s see what will be the results.

i will share more pictures of that custom manifold.. maybe you can copy the same. Happy to see your engine rebuilt went well.. those are great numbers.

gearsoft

Dilshan, I'm thinking that the roots blower is linier and that as long as we don't go over the max rpm it will keep pushing more air and give a higher boost. I think the reason that the boost tappers off at high motor rpm is that the rotary is pulling more cfm then the blower outputting so there's not as much backpressure (boost). If we decrease the pulley on the blower or increase the drive side it should up the cfm output give more boost as long as we don't exceed the max rpm of the blower. I'll look at calculating the current setup blower rpm and see how much pulley size we can add.

As for the manifold anything you can help with would be great. Mainly at this point what tubing sizes you're using? Is that a 2.5" or a 2.75" for the main tubing and a 2" for the boost controller? I am drawing it up right now in autodesk inventor and can probably have it fabricated from that. (Hey if that works I might just draw the other side too and look at offering a kit with the tx12 in it and either a standalone ecu (ADAPTRONIC) or a piggy back along with the Arduino controls and a boost controller...)

Just started the cad drawing and got stuck on the tubing sizes...

Thanks for your r&d on this and for helping motivate me too!

Dilshan Liyanage

Thanks for the information,and that’s a good news.so i did some research and found ogura tx12 is similar to toyota Sc12 superchager,(think both made by ogura) but tx12 is bit more updated and efficient.found plenty of people running 10psi or more on sc12. I think increasing boost pressure to 10 psi is not a issue. it’s easier to make a slightly bigger alternator pulley for this. So we increase the belt area (good for belt slip) plus can keep the magnetic clutch.


Regarding the tube size I went all way 2.5 inch tube size.i did’t change the original tube sizing for the pressure bypass actuator side.(boost controller) think it was originally 2 inch.

Since i’m experiencing a pressure drop and slight throttle lag thinking to change the supercharger outlet side tube to 2inch till the intercooler inlet(hot side) and after the intercooler 2.5 inch all the way to engine.(cold side) Found lot of system use this pipe size..i think greddy turbo system also uses the same piping method.Hope this can increase the throttle response and help the pressure drop.yet again a theory. Most probably i will do it next week and can share the results.

Thanks for your R&D too.. hope we can get better outcome from this.i think you have lot of knowledge and ideas. If i can get closer to 300 whp i’ll be more than happy. I will share the tx12 specs.. so others also can get a idea. Let me knw if you can find anything regarding the alternator pully size to run 10 psi.

My plan is to get rid of the Blitz piggyback box and give a direct voltage(12v)to superchager clutch to keep it engaged all the time and tune it with versatuner..I will put a switch to power off the clutch if required..So i can turn off the supercharger for lazy driving.Want to keep it simple.what do you think?do you think versatuner will be able to tune this? I’m lack of tuning department.

thatguy308

Wow, very cool project.

gearsoft

I guess I'll wait to see how it goes with the tubing size change you're making before I finish drawing the manifold.

Great work on researching the blower. I found an article that's pretty interesting about the MR2 Toyota (can't find it right now). Also saw this video that shows how they're using a bypass like I'm talking about doing.
I was trying to calculate the final rpm of the supercharger but I couldn't find my alternator pulley so I just took a guess at it and called it 80mm. Can you try to measure your alt pulley that drives the SC and let me know what it is or just plug the numbers into the spreadsheet I uploaded.

If this is right then it's already max'd out.

TeamRX8

iTrader: (25)

if I calculated it correctly and making a mountain high pile of assumptions, 5.5 psig would be approx. 270 whp based on the chart above

in reality it’s probably less.

.

Dilshan Liyanage

OK guys I'm back on business . finally managed to recover the lost pressure. Default pressure increased from .24 kpa (3.5 psi ) to .37 kpa (5.4psi)so with the boost controller i can increase the pressure up to 7.5-8 psi. Average pressure drop with the setup is 0.6 psi now, which is very good.

made following changes

1 As I mentioned in an earlier post, intercooler pipe size was changed 2.5 to 2 inches on the hot side (staggered pipe setup).

2 Air filter moved to front bumper (this made a huge intake temp drop)

3 Replaced the intercooler to a Deltafin one from bar and plate. new core size is 20x8x2.5

4 replaced all the hose clamps to super clamps.

5 found a vacum leak and fixed.

ok this made huge difference. now throttle response further improved..lag is almost unnoticible.made a 5.2 psi pull and my rear went almost uncontrollable.can feel a very good power. i never wanted to increase the boost as i'm still on original Blitz fuel control box.definitly car needs a new tune. But what a difference!

Gearsoft, sorry still i coud't calculate my pulley size, but will let you know. Honestly, I'm very happy with the current results.i thinlk increasing the pully size to 10 psi is not a issue, saw lot of mr2 guys runing 12 to16 psi on sc12 using oversized pullys,( http://mr2.com/TEXT/SuperChargerInfo..._QQdD2tEirUR9w )

TeamRX8

iTrader: (25)

You might try to remember that a rotary engine needs about 30% more airflow than a reciprocating engine for the same power output level. Then also the additional fuel to maintain the correct AFR. That’s why fuel mileage on a rotary engine is what it is.

I’d be leery of the size 12 being capable of that boost level within the maximum speed ratio limit it has.
.
.

jcbrx8

Congrats Dilshan for getting things sorted. That's why we do this: more power, the challenge of solving problems, creating something unique, and enjoying the journey and product. 6-8 psi should put you in the ~ (270 - 310) wHP range. Enjoy.

Dilshan Liyanage

Thanks to everyone for all the valuable inputs.

Gearsoft,
I managed to calculate my pulley size diameter and insert it onto your xl sheet(rough calculate). Are you sure that your crank pulley diameter is 177mm (inner one)? If that is so, you are already maxed out at 9500 engine rpm sc rpm14327 ?you should be able to get 9 psi or so with boost controller

Since I have a lightweight underdive pulley set, my crank pulley diameter is 110 mm, the same as the SC pulley (rough calculation with the belt on).
so at 9500 engine rpm max sc rpm is 11626






So let's say we increase the alternator pulley size to 95mm. At 9500 rpm, the SC rpm is 13470. That's below the max short time rpm. I think that is acceptable as we don't always exceed 8000 engine rpm.



So at 8000 engine rpm, SC rpm is 11343 with a 95mm pulley size. I think this is acceptable as we are close to the max continues rpm



So I made this calculation
8PSI(MAX) divided BY 82MM PULLEY SIZE (current setup ) [8/82] = 0.0975
0.0975 multiplied BY NEW PULLEY SIZE 95MM [0.0975x95] = 9.268 PSI

This is a rough calculation to get a idea what 95mm alternator pulley will be like, so we can increase the boost to 9.3psi approx if my calculations are right.

Dilshan Liyanage

Here some updates..

Finally managed to make the custom pulley as said above




and i made a electric bypass system to fully open close when i want.. this way i can control it with a switch.. so idea is to run N/A with supercharger disengaged..and i have a separate 12v switch to turn on/off the supercharger when i want.. planing to add a air diverter valve with a 6psi spring to control the boost.






so with a new pulley i wanted to test the boost.. and made a one pull with a blitz piggyback connected and i saw 0.6 bar psi and that was closer to 9 psi which i was calculated. decided not to play anymore as i wanted to tune this properly. So this is the final setup..




i had a issue of stalling idle after revving above 4000 rpm and that was there from the day one after installing the intercooler and i checked vacuum leaks, cleaned the maf nothing can solve the problem. So i installed varsatune and decided to play around with Throttle position map..and made some changes and managed to get rid of the issue.. throttle response also now greatly increased.now throttle is so smooth with the N/A mode and no more stalling after revving the engine.


as i have no previous experience with tuning decided not to touch anything with fuel,ignition related maps..

is there anyone who can remote tune this with versatune ? as i don’t have any local tuner to do the job.@gearsoft can you do it ? or anyone else?

gearsoft

Dilshan, Love the new mods! I'm still waiting to put my SC back on till I smog. But I would be so grateful if you had a cad of the pulley or at least just the dimensions you used so I can copy what you made. Were you also able to reuse the same belts? The spring pressure on the bypass looks like it will work great but I like using the Greddy boost controller I have and an Arduino to hold the bypass open while in NA so I think I'll just stay with the setup I have for this. I'm also really glad that you have the Versituner software as so do I and with the latest update 22.1.6.0 they have additional rx8 gen 1 tuning support!
Here's a few things from they're site that I think I'm finally on board with using it to tune with:

"The OEM Mazda RX-8 ECU tuning tables are limited to low loads of naturally aspirated engines and are quickly maxed out when a turbo/supercharger is installed. VersaTuner allows you to edit the axis values of tuning tables, so you can precisely control the engine even at higher than stock loads or RPMs.

It can also automatically interpolate the table values so that engine operation at normal loads remains unchanged. All this allows you to create robust and accurate tunes for turbocharged or supercharged Mazda RX-8 vehicles."

I did successfully tune my car with the e-Manage piggyback pulling multiple runs and editing the maps to keep the AFRs in the low to mid 12s but Versituner will let you base the timing and the injector duty cycles on engine load and lets you modify the table axis to increase the normal loads, RMP, etc that the a NA maps use and also use them to run both in NA mode and SC mode with the same maps. Too complicated for me right now to be honest so I'm going to hire an e-tuner from the list of tuners on Versituner's site. Maybe after I see their mods I'll start doing my own. Here's the list of tuners: https://www.versatuner.com/etuning. I also am looking at wiring in the MAP sensor into the MAF input and remapping the input but I'll ask the tuner if that's really necessary or if the stalk MAF can handle it. I'm using an addon AFR sensor with an LC-2 Digital Air/Fuel Ratio (Lambda) Sensor Controller for the e-Manage and also to readout the AFR inside the car. Do you have an AFR? I guess you can just use the stalk one since you're using Versituner but I think it's good to be able to watch this while you're in boost.

Don't forget that Versituner works great to set dwells aftermarket coils, increase oils injection and set your cooling fans to come on sooner...

Anyway, congrats on the awesome work!!