AnimalCrackers

Hello all, I am pretty new to Rx8's in general, and especially Turbo-Charging a car. After doing a lot of research on the subject I thought I'd ask for help to possibly validate/correct any information/parts-lists I have gathered.

First off ill state what my goals are for the car. I have a 2004 Rx8 GT 6 speed 6 port, and I'm looking to have a reliable 300 RWHP at possibly 10-12 PSI of boost, so probably a good 340-350 HP at flywheel. I've scoured multiple threads on here and found its pretty achievable already with kits like the Rx8Performance Turbo kit with the Precision 6266 dual ball bearing with a .82 a/r T3 V-Band.

Thing is I want to try and save as much money possible by building the kit myself (including making the exhaust manifold + stainless steel piping, as well as learning a Tuning software and flashing self made tunes) so lets call this a "DIY/budget" setup (I didn't put this in the DIY section mainly due to it being about everything I'd need for HP gains rather than a detailed list for something specific.)

With being new to this entire thing I've mainly based my findings off of other kits created by companies as well as turbo setups I've seen here, so far here is what my general setup would entail:

Turbo: Precision 5862 Journal Bearing W/ .82 A/R T3 V-Band (I choose journal due to it being a cheaper option, I could not find much stating it will be too big of a performance loss)($1200)

Wastegate: 44mm Summit Racing Wastegate (Using either the 6.1 or 5.5 PSI Spring, depending on how much Boost before Boost Controller) ($100)

BOV: Not sure, still doing research into choosing a good Blow Off Valve for my application, recommendations very welcome.

Boost Controller: Possibly a GReddy electronic Boost Controller, but for $374 I am considering going for a manual controller.

Boost, AFR, and Oil Pressure Gauges: Not Sure yet.

Intercooler: Treadstone TR8C Intercooler (Core 7.8" X 22" X 3.5") ($280)

Apex Seals: Possibly Goopy Apex Seals?

Corner Seals: Atkins Rotary Solid Corner Seals ($90-100)

O-Ring Kit: I have an Atkins Rotary O-Ring Gasket Kit ($180?)

Port: Street Port (will be done by self)

Oil Pan: High Capacity Oil Pan from Rx8Performance ($430)

Possibly a Solid Dowel set, and Turblown Rx8 Engine Stud Kit as well if needed, couldn't hurt to overkill for better reliability.

I've seen people get torn apart for these kinds of threads due mostly to unreasonable expectations with a Renesis, and maybe my goal is unreasonable, but I'm hoping it's somewhat attainable especially for a "newcomer" to all of this.

Any and all recommendations/help on this topic is appreciated, it's obviously easier to just go with a premanufactured kit + everything included but I'd like to learn while I have the opportunity even if it won't be the easiest, if there's already a good thread I couldn't find for basically my same situation I will delete this thread, same if it needs to be moved, thanks!

Brettus

iTrader: (2)

New to rx8s, new to turbocharging and wanting to do it on the cheap ...........what could possibly go wrong ?

turbo : good
WG ... ok
EBC ... Greddy is good
IC : good
Apex seals etc : only if already doing a rebuild otherwise stock engine is ok for your goal
Porting : don't bother
Oil pan : don't bother

Brettus

iTrader: (2)

Also ...learn to tune it NA before you even think about FI tuning!

AnimalCrackers

Hey Brettus, I appreciate you taking the time to respond and let me know that my future setup so far would work for my goal.

And yes, being new to all this and trying to do it cheap is usually a recipe for disaster lol, but I'm mainly doing it "cheap" by doing it myself or using connections to fabricate things that would normally cost a lot (like a custom stainless steel manifold, piping, and custom engine mount to fit the manifold and turbo)

And yeah I am already doing a rebuild due to buying the car with low compression, might as well go with more expensive + reliable internals while I can.

Any reason to not bother with the oil pan? I thought it was oil cooled and needed extra oil + a tapped oil pan. Could I basically tap a stock pan and wouldn't need to worry about any oil loss to the engine/enough for the turbo?

I might end up having the car dyno-tuned depending on how difficult I find NA Tuning then, or if there's good pricing in my area.

Again I thank you for giving your insight, I read through a lot of your threads on turbo charging while researching everything I'd need so they helped a lot. If there's anything else I might need or other recommendations I'm all ears.

Brettus

iTrader: (2)

Oil pan : everyone seems to think they need this ..... i've been running a stock pan for years including multiple trackdays without issue. For drain it depends on if top or bottom mount ...for bottom, just weld an AN 'weld nipple' to the side of the pan and you are good.
For rebuild :rx7 apex seals , rx8 corners with grooved plugs , plus 11mm stud kit and oil press increase.

AnimalCrackers

Good to know regarding the oil pan, I will be doing a bottom mount due to reading its generally better all around compared to a top mount besides space.

For the Rx7 apex seals, I imagine you're referencing Rx7 REW or Turbo II apex seals, but for any Rx7 Seals I would have get the Rx8 rotors machined to fit said seals since they are deeper right? I'm guessing the grooved plugs on the corner seals ties in with fitting deeper apex seals but I can't find any threads or other sources that explain their purpose. Are Rx7 Apex seals better than basically any aftermarket Rx8 seals? At least for turbo application?

Brettus

iTrader: (2)

Yes re machining rotors . Yes re grooved plugs. The deeper seals are better because they have more side bearing area ......no other reason. Think of putting a fence post in the ground 4" and working it back and forth ...now bury it 3 feet down and do the same. Same effect with deeper apex seals. The stock seals are fine NA but for FI the side loads are doubled which increases wear significantly.

AnimalCrackers

Makes sense! It looks like mazdatrix does the machining work for $500 or so, and Rotary Performance does it for $200? but ill check around me as well if there are any rotary specific shops.

Now I guess I should ask what kind of Rx7 Apex Seals should I go for? Should I aim to have the Rx8 Rotors + Plugs machined to fit 2mm Rx7 Seals, and purchase something like the FD Rx7 2mm PowerSeal apex seals? Or machine it to 3mm, and purchase the Rx7 3mm PowerSeal Apex Seals.

There's also Turbo II Seals but I'm not sure if they would be better or if there is a significant difference.

Brettus

iTrader: (2)

I just use stock Mazda 2mm rew apex seals (3mm can be problematic on Renesis rotors) .... there are many arguments for and against after market but I'm not going into that ... search rx7 site if you need more info.

RotaryMachineRx

iTrader: (1)

I think you have a pretty good looking list so far and your goals are definitely achievable. I ran an HKS SSQV BOV for years just vented to atmosphere without issue, although I'd say 90% of the forum will say recirc the BOV back into the intake post MAF. Recirc is technically the better options, just wanted to state that I was able to run that particular BOV in a a VTA configuration without issue. If you are looking for any budget areas I would skip the boost controller for now and just run your wastegate on spring pressure. An EBC is always easy to add after, I recommend a good electronic EBC (I have a greddy Profec that once I had set-up, was basically a set it and forget it kind of scenario).

For your gauge selection, I'd argue that Fuel Pressure will be more important than Oil Pressure if you had to choose just one of the two. In my experince I'll see my fuel pressure gauge drop off prior to my AFR's being affected letting me know I need to get off the pedal. Typically if you see the AFR gauge lean out, specifically under boost, it's likely too late.

You are going to want a larger than stock exhaust setup for going FI. Anything to reduce backpressure and EGT's will go a long ways for engine longevity.

IMO the most difficult part of this DIY project is going to be the exhaust manifold fitment.

I think it's also pretty common for people to stick with stock corner seals. From what I've read the Atkins seals wear the irons more.

As Brett mentioned, Rx7 deeper apex seals are a great upgrade, there is sooooo much info on brands for these it's not worth clogging up your thread with. But stock Rx7 seals will be just fine at 300whp. If you do want to look at aftermarket you mentioned Goopy which is a popular brand and will likely serve you well also. I personally went with some E&J apex seals on my most recent engine but these are slightly more expensive than goopy. Rx7club has Apex seal info for years, but no guarantee you'll read all that and have any better idea of which way you'd like to go They are just one of those things everyone and their dog has an opinion on.

Like mentioned, porting doesn't really gain a lot on the Renesis, but that doesn't mean you cant go a clean/smooth all of the ports out for a more laminar flow while you have the engine apart, I just wouldn't spend much time focusing on enlarging the ports.

Other than that, Brettus has a tremendous amount of experience with these engines and setups. He had mine running like a top for 9 seasons before I decided to change things up. The one thing I see missing from this discussion is your fuel setup. Brett has a thread or two will excellent information on recommened injectors. You should be fine upgrading to a DW200 fuel pump, or DW300 if you plan on using any ethanol fuels.

Consider replacing your ignition coils with either new Mazda ones, or from my personal experience the BHR coils lasted the life of my boosted Renesis and then I was able to sell them in still perfect working condition when I swapped.

Cheers!

Brettus

iTrader: (2)

I know others that have said the same ... I think it's because of the two step opening sequence these have. Most BOVs will cause massive backfires if run VTA.

AnimalCrackers

Great to know, I'll check out all the threads regarding aftermarket VS OEM Rx7 REW Seals on Rx7Club.

AnimalCrackers

I really appreciate your insight on this! It's been good to hear so far that my goal is achievable from you and Brettus.

Good to know about the BOV and venting it into the atmosphere or not, I will try and recirculate it after the MAF as you said.

Also good to know regarding the Fuel Pressure gauge, I'm still doing research into what I'd like as a gauge setup but I'll aim for fuel pressure first. Planning on eventually ending up with at least the Fuel Pressure, Oil Pressure, and Boost gauges.

Definitely will be going with a larger exhaust setup, I already have something that came with the car but its only axle-back, will purchase a good downpipe as well.

Regarding the exhaust manifold, I'm first going to attempt to make a stainless steel one myself (after using plastic parts to mock up a manifold and making sure it all fits, including Turbo) and if I can't ill look into premade manifolds for Rx8 T3 Turbo application.

I will most likely end up going with OEM Corner Seals, and having them grooved to fit 2mm Rx7 Seals.

Both of you guys have mentioned there are many different opinions on aftermarket VS OEM Rx7 Apex Seals, so I'm definitely going to be scouring Rx7club apex seal threads for the next week or two trying to come to a decision lol.

Rather than porting I'm going to do exactly what you said and just smooth the ports out more for better flow.

And yes, I haven't been fully sure about a fuel setup yet, I wanted to go E85 but need to research more about its benefits and disadvantages, as I don't know a ton about it yet.
I'll look more into the DW200 fuel pump, as well as high CC injectors that would fit my application, I'll check out Brettus's threads regarding those as well.

I believe I actually bought the car with BHR coils but I'll have to check, I know they were swapped a couple times while the previous owner tried to rebuild it.

Again I appreciate your help a ton, if you have any other recommendations feel free to let me know!

RotaryMachineRx

iTrader: (1)

In regards to gauges. You'll want a way to monitor AFR. IMO this is the sole gauge that has the highest priority over any other gauge. Now this can be monitored with an OBDII reader, but make sure it's something that you have a visual on at ALL times. FYI, Lotek makes a good and fairly easy to install center gauge pod for 52mm gauges. This seems to be a bit old school nowadays due to how advanced many of the aftermarket ECU/Dashes are, but I'm assuming you'll stick to the stock ECU and having it flash tuned. Here's an example of my gauge setup that I installed with my boosted Renesis. My current setup has all of this info directly measured by the ECU now too, but I left these in as independent indicators and they double up nice to confirm my ECU is reading the same values. You'll notice, up front and center is my AFR gauge (AEM UEGO). Still the gauge I monitor/glance at essentially every few seconds under all conditions while I'm driving.

AnimalCrackers

Nice I really like how your setup looks, I was considering a 3 gauge setup like that before cause I don’t have the OEM GPS.

Honestly even if older I want to go with a more mechanical setup first since it’s a bit cheaper and might be easier to install while not being as invasive as a new screen to plug into my OBDII reader/replacing the dash for electronic readings. I’ll probably get a laptop for reading codes/electronic gauges/saving tunes and keep it in my passenger seat lol.

And yes I was planning on having the stock ECU flashed tuned, possibly with Versatuner or MazdaEdit, but it really depends on how I’d go about getting the car tuned and if it’s like dyno-tuned or not.

Regarding the AFR gauge, what am I meant to look out for when driving? I imagine it will change depending on how my car is tuned and will change consistently with RPM, am I basically just watching out for abnormalities?

RotaryMachineRx

iTrader: (1)

It's not so important in vacuum. At idle you'll see around 14.5, will dip a bit richer under load (maybe 14.0ish)...... but under boost, thats where you want to see around 11.2 or richer depending on how much boost. If you go leaner than that you risk pre-detonation, extreme EGT's, and overall just less coolling and lubrication from the fuel. FYI, you will want to add premix to your fuel when boosted. Roughly 8oz per tank should suffice if you keep the OMP operational.

ethanlee197@icloud.com

I got a brand new turbo kit never used I’m trying to get rid of. It won’t let me post pics yet that’s why I’m commenting on here. Lmk if anyone interested. 1K obo

Loki

iTrader: (1)

Personally I don't see any point to an AFR gauge. You want to read AFR as a curve vs boost, rpm, load, etc., while tuning and it the tuning is done right, you don't need to monitor AFR while driving. It's running in closed loop most of the time anyway. Conversely, by the time you notice AFR problems on a gauge, it's probably too late and there's not a ton you can do about it. It's not useful at best, a distraction at worst.

Source: I had one on my old car, which was boosted.

Brettus

iTrader: (2)

Well if you don't know what to look for and are not concerned with keeping your setup optimal ...I'd agree.
For me and those I tune for I consider it essential.

Loki

iTrader: (1)

What action are you taking from an AFR gauge reading while driving?

Brettus

iTrader: (2)

In tuning phase it is critical to monitor if you are street tuning ( laptop wont cut it for that - too dangerous). Also critical if making any changes to system or if system is dismantled to check it's not gone rich or lean for first few runs. Then over time it's critical to monitor the tune periodically to make sure it hasn't drifted away from initial settings and become lean or rich under load. On top of that ...it's always the first gauge to look at should the car start behaving oddly . An essential gauge IMO but not one you have to constantly refer to once you know the setup/tune is working as it should.

ciprianrx8

I agree with just one statement of yours: "by the time you notice AFR problems on a gauge, it's probably too late". That doesn't mean computers can't do something faster than I can react, and that's exactly why I've gone to great lenghts to guard myself from myself. There are programmable AFR + boost gauges that sound a horn if boost > some level and afr > some other level. At least that much should be run in any boosted car.

The rest of the statements I disagree strongly with so to avoid flaming I'll stop here.

Loki

iTrader: (1)

I hear you, and we can disagree without flaming
My point is that, alarms aside, AFR monitoring is better done with a logger where you can correlate AFR with other data and make decisions from there. If you're at full boost, you're probably going somewhere fast and should be watching the road, not your gauges. But it's a free world, you can do all of the above.

AnimalCrackers

Sorry for the late response started a new job, but that’s good to know for future reference.

And yes I was already planning on premixing even without boost cause I want to make sure my engine lasts more than 70k miles lol, but thank you for adding an amount that helps a ton.