texastboneking

Its a tdo5h turbo. 14b for starting off and from what I've read should be good for close to 300hp. If I ever get to that point I'll upgrade to the 16g and be good for over 350. If I really wanted to push over 500 there is the 20g... I'm having a bud build the manifold. Stainless steal. He is a pro at what he does and guarantees no leaks or cracks. He will be building the downpipe also. I'll consider the lower injectors for now. And if I upgrade more I might buy a larger set. E85 is not all that common here so I don't want to have to rely on finding some.

StratoBlue1109

iTrader: (1)

I missed that it was a TD05... The RX8 injectors will still work well with that turbo, but you'll likely want a fuel pressure regulator with boost reference to maintain flow if you turn the boost up much past 10-12psi. Your NA runs a lower base fuel pressure than my 03 so the injectors will flow less and support less HP. But this is easily remedied by using an adjustable fuel pressure regulator and seting the base pressure to around 55 psi, then hook up a boost line to the FPR and you fuel pressure will increase 1 psi per pound of boost. This will offset the delta in pressure in the manifold and maintain your injector flow under boost which will help your injectors support more HP.

My recommendation to all of my customers is run the smallest injectors necessary to support your horsepower goals, and run way more fuel pump than you need. It's much easier to get smaller injectors to perform well at low pulsewidth (idle and cruise) and still flow enough fuel under boost with a big pump and an increase in fuel pressure. Plus the increased fuel pressure improves atomization, further improving drivability.

texastboneking

Still need to research that or someone explain it to me.. In the mustang world we would just sorry more fuel without really turning the pump up. But I've read a thread there the guy doubled his fuel pressure. I don't get this because I'm used to just seeing bigger injectors for more fuel. Not turning up fuel pressure.confuses me a bit lol

StratoBlue1109

iTrader: (1)

Injectors are rated at a set pressure. So for example the RX8 injector flows 480cc/min at 43.5 psi (most injectors are rated at 43.5 psi). If you lower the fuel pressure to say 35 psi, the injector flow will decrease. A VERY rough estimate would be to divide the new fuel pressure by the rated fuel pressure and apply that correction factor to the rated flow.

For example:
30 psi (current pressure) / 43.5 psi (rated fuel pressure)= ~0.69 <~~~ correction factor
480cc (rated injector flow) x 0.69 (correction factor)= ~330 cc/min
So if you lower your fuel pressure your 480cc injectors will actually flow like 330cc injectors.

Now if you raise the pressure to say 55 psi it looks like this.

55 psi / 43.5 psi = ~1.26

480cc x 1.26 = ~600 cc

So by simply raising your fuel pressure your 480cc injectors will flow around 600cc/min, which is a substantial amount of fuel.

The only caveat is that your fuel pump must be able to keep up with the increased fuel demand, and typically fuel pump flow decreases pretty rapidly with an increase in pressure. So if you oversize your fuel pump, a 255 lph pump to support 300 whp is quite oversized, you can run the higher pressure, support more power on smaller injectors, and gain improved idle and drivability from the improved atomization. Everybody wins!

Chiburbian

iTrader: (1)

While in general smaller injectors tend to give better low rpm low load precision, modern injectors like ID1000s are just fine even when dinking around town.

It has more to do with the injector technology than size at this point.

triple88a

iTrader: (2)

800s dws arent hard to tune for idle. I can idle mine at 15afr all day long. Which i actually do.

Fact that in the summer i can switch to E85 without having to do any bolting is a rather nice bonus. That said DW800 or similar is a much better choice than a smaller injector.


Btw Trent, have you done any internal work on the motor? Dont remember reading that.

texastboneking

currently no. one reason 225 is the goal. i hear that is a safe dd hp limit. 250hp is apparently when the rods like to bend. next years tax return im planning on going forged for more power.


side question. the test pipe and aem a/f gauge came in today. when installing the gauge should i get a hole made into the test pipe for the sensor? or do you remove the factory rear o2 and just program it out of the pcm? is the rear o2 port too far back for a good reading?

guess what im asking is where is the best place to mount this sensor right now without the turbo manifold and downpipe installed? i would like to put it in a part that i wont have to replace when i get the manifold and downpipe installed. if at all possible.

sixshooter

iTrader: (12)

What does the manufacturer say?

StratoBlue1109

iTrader: (1)

You can mount the wideband in the rear O2, no problem,for NA tuning as response is less critical.

Once you put the turbo on, move it closer to the engine. Usually 12-16 inches away from the turbo outlet works. That way you get good response but don't risk cooking the sensor.

You'll probably need to adjust the PID loop in Megasquirt to offset the transport delay caused by the sensor being further downstream, but no big deal.

StratoBlue1109

iTrader: (1)

Why is $400 worth of injectors better than $100 worth of injectors if the $100 injectors will support your power goals?

I've never had great luck with DW injectors, but most of my tuning is OEM flash programming, so injector data and response is VERY critical, but hey YMMV.

Chiburbian

iTrader: (1)

Strato, it isn't the cost that is the real issue, it's the technology.

Both the $100 injectors and the $400 injectors will work, but the $400 injectors are more likely (than the $100 set) to be EV14 or something similar. They will have better spray patterns, better dead times etc. By all means, run what works for your application but at the same time don't be afraid of running big injectors if they are newer technology. Specifically I am referring to the ID1000s that many people here run.

StratoBlue1109

iTrader: (1)

I agree that ID's and any EV14 injectors are great, and necessary when your power levels warrant the need for large injectors. But the OP stated he's working with a tight budget. RX8 injectors are EV6, which are still light years above the RX7 and Supra injectors in terms of control and quality, and the same in terms of quality as the NB2 OEM injectors. If he can avoid spending an extra $300 on something he doesn't need to reach his goals, then why not?

concealer404

iTrader: (3)

ALLOFIT

Chiburbian

iTrader: (1)

Good point. So much discussion happened that I forgot that the guy was on a budget.

I sent the OP a breakdown of what I paid for my turbo setup, but here is a link to what I think you should pay and how you will meet the budget:

Manifold, used: $175-275
Manifold, new: $400
Acceptable manifolds are Flyin Miata or Begi. Might be others but ask opinions on any manifold you find that ISN'T an ebay tubular

Downpipe, used: $150-350
Downpipe, new: $505
Flyin' Miata has a DIY manifold + downpipe kit. It's new so you are paying more but it is solid parts... Flyin' Miata : Turbochargers : Parts and upgrades : DIY turbo manifold/outlet/downpipe

Megasquirt: $450-700 depending on options
Wideband: $180
Injectors: $70-150

Clutch: $300 (approximately)

Piping and elbows and stuff for charge pipes: $120
Ebay intercooler: $100-200
Turbo: ???? all depends on what you want $100-1,800
Turbo oiling and cooling: $50-400 (anything from rubber hoses to BEGI distribution block)
Air filter: ?
Assorted other costs: $200

That is just off the top of my head.

texastboneking

been busy with work and stuff. finally got around to installing parts! still have a lot of parts to order and a lot of parts on the way . just got the megasquirt installed today. took forever for me to figure out how to get it to idle down.. think i set the timing right. going to spend alot of time trying to figure it all out as it stumbles under light acceleration and i think i might be hearing it ping in low rpms under load... so going to recheck timing tomorrow. gonna spend a lot of time reading in the tuning section. would i be safe making a post in that section for me to explain things out and get advice? total newb to tuning so dont want to **** ppl off in that section for asking possible stupid questions. taking time on this build to make sure i do it right (and to keep from starving my wallet. im seeing to do this right its gonna cost a bit more than my initial plan but thats ok ill save up as im going.)

texastboneking

been a little while since ive posted (been a while since ive got to really work on the car...) anyways. made a quick video showing off the launch control feature of megasquirt


sending the two turbos i have off to get rebuilt and balanced. keeping one as a backup. getting closer and closer.. texas weather decided my car shouldnt look good.. so its gonna be an ugly "fast" car lol

more to come in the next few months as it starts coming together


edit.. dont know why the video is posting twice...

Chiburbian

iTrader: (1)

Ouch! We had hail like that a couple weeks back. Nearly caught a couple friends but they were able to duck under an overpass before the heavy stuff came down.

Twodoor

iTrader: (2)

Driving me nuts seeing yellow RX8 injectors called 480cc. They are 425cc injectors. I (and anyone else who has them cleaned and flow tested) know they are 425 because I have the flow sheet that shows before cleaning and after cleaning results. And yes they were tested at 3 BAR (43.5 psi) There are larger RX8 injectors from other than the North American market that flow more. They are blue or purple depending on who you ask and don't idle worth a ****.

About the 14b, it is a great TD05 turbo, that in the stock DSM application puts out 11 to 12 psi... but this is because the DSM's have a boost control solenoid bleeder valve that ups the the boost 4 to 5 psi above the wastegate spring pressure. They did this so when some idiot put 87 octane in the car it would sense the knock from the low octane and close the bleeder solenoid to lower the boost pressure. This means that you should get 7 to 8 psi out of your wastegate actuator before putting on a boost controller.

Keith

texastboneking

been a while since ive posted. turbo is still happening. just might take 2 years of tax return to finish it lol. i have received 3 free turbos in the last month (pretty sweet lol) 2 need rebuilding. one is good to go. the good to go one is big though. really big. i dont mind it being big and having some lag if it is capable of spooling. so im googling like crazy trying to find out what big turbos have been used on miatas. so far the hx35 seems to be the biggest i can find. if this big one cant be used then ill just sell it and use the money to rebuild one of the smaller ones. the small ones are tr0760 garretts with .48 compressor a/r and .45 turbine a/r. ive been told i could safely get 250ish out of one of these turbos. the big turbo is a garrett. the only numbers i can find however are the a/r numbers. compressor is .60 and turbine is 1.15 turbine. any input from the guys with experience will be awesome. (pretty sure this turbo will not be usable for me)

texastboneking

lots of googling later the turbo is a garrett t04b