The EFR Turbo Thread

[The American]

I've searched this forum and it does not appear that too many have ventured far from the Garrett fold when adding forced induction to Mx5's in Australia.

From what I can gather, RXMX has a car so endowed, Timk put one together (sold) and Lokiel is working on one and has documented his ongoing EFR adventures.

Are there any other lurkers who have EFR experiences to share?

[NitroDann]

Ive done a few, what questions do you have?

Dann

[The American]

My question leaves it open for people to tell what they they think stood out from their experience. For that reason I did not have a particular question in mind, but how about these:

Which one did you use - 6258 or 6758?
Did you achieve your power, and power delivery goals?
If happy to share, what did it make, (dyno graph to share?)
Fitment - did you have any unique plumbing or mounting challenges?
Boost control - where you able to eliminate boost creep or otherwise control boost?
Waste gate - did/does yours blow open, under what conditions, and how did you manage it? Could you achieve the waste gate control you wanted with one of the stock actuators?
If your car previously had a Garrett (which one?) how would you describe the difference in power delivery and response?
What was going through your mind just before your gear box detonated?
If you're in Brisbane, would you be happy to take me for a drive around the block?
Etc....

Lokiel's experience is pretty much the only detailed account here, and I thought it would be useful to hear from others.

My personal interest is a future upgrade for mine. I've got a 2560 + e85 producing 256hp, and its really good fun to drive. However, I don't think I'd be prepared to sacrifice response for more top end. An EFR might be the way to go?

[NitroDann]

My question leaves it open for people to tell what they they think stood out from their experience. For that reason I did not have a particular question in mind, but how about these:

Which one did you use - 6258 or 6758?
I've been involved with 62 series EFRs and also much bigger ones on other projects, currently my shop has a 1000whp commodore with a huge Borg on it.
In terms of mx5s, the 6258 will scare the living sh*t out of 99% of people but the 6758 is the pick based on international dyno sheets and discussions.

Did you achieve your power, and power delivery goals?
sh*t yeah, the turbos are the earliest spooling turbochargers currently available per hp. Nothing else that can make 400whp will spool like a 6258 right now.

If happy to share, what did it make, (dyno graph to share?)
Google like mad and head on over to miataturbo and read some build threads.


Fitment - did you have any unique plumbing or mounting challenges?
The EFR series is particularly long, a couples of inches longer than a similar 5 bolt garret or v band precision, and as lokiel has pointed out, the round bar style threaded wastegate actuator -> flapper door arm connection is more sensitive to odd angles than the sloppier garret style internal wastegate connection, but its not a hard fix and the EFR has the BOV and wastegate built in, AND you can mount the wastegate actuator canister anywhere radially without having to weld aluminium brackets to the compressor housing like I usually have to on a garret.

Boost control - where you able to eliminate boost creep or otherwise control boost?
You want creep. Let me repeat that. You want the creep. On a stock mx5 head you absolutely have to have the boost rise with RPM after the midrange delivery of initial boost if you want to make big reliable power and have something that resembles a flat torque curve. If the setup doesnt achieve this mechanically i always tune it in with electronic boost control, there is a few reasons my builds are the highest hp stock motor builds in the country AND they dont fail. This is one.
Having said that the creep issues are overblown. Check the track speed manifold thread over at MT, Andrew has a 6258 on hisbtest car making only 200whp just to prove it.


Waste gate - did/does yours blow open, under what conditions, and how did you manage it? Could you achieve the waste gate control you wanted with one of the stock actuators?
Not on the setups I have dríven or done fab work for. With proper closed loop ecu based boost control there are very few setups anywhere that can't achieve the torque curve you are looking for. But there are a tonne of poorly setup turbochargers which misbehave due to lack of experienced setup and tuning.


If your car previously had a Garrett (which one?) how would you describe the difference in power delivery and response?
The EFR series can be looked at 2 ways compared to a GT series garret, you either can say "it makes 30% more power" or you could say "it ramps up onto boost 30% earlier". The biggest difference however is transient response. Sure having a car that comes on HARD at 3000rpm rather than 4000rpm is nice, but your tyres/street clutch/skill/gearbox probably won't like that anyway, but what everything will like is how snappy the throttle is above the boost threshold. Old bush bearing turbos have that feeling where you are at 5000rpm and you snap the throttle to the floor and you have to wait for the turbo to START spooling. Garret GTs start spooling immediately but you have to wait for full boost, the EFR range will literally go from vacuum to target boost as fast as your ankle can move if you are above the boost threshold rpm.


What was going through your mind just before your gear box detonated?
The torque limits of the 5 and 6 speed are well known and understood. Breaking them if they were in good condition, on a road tyre is not a concern on a well setup car. Kens ('crons_rotary') na8 is a rods/studs only build with a 5 speed and makes nearly 290whp. On a log manifold. On gasoline. And it gets -driven- to the track to collect trophies every month. And to work every day.

If you're in Brisbane, would you be happy to take me for a drive around the block?
Etc....

Lokiel's experience is pretty much the only detailed account here, and I thought it would be useful to hear from others.

My personal interest is a future upgrade for mine. I've got a 2560 + e85 producing 256hp, and its really good fun to drive. However, I don't think I'd be prepared to sacrifice response for more top end. An EFR might be the way to go?

Seeing as how you are on E85 you can do a tonne of good things, you have the option of buying a cheap and available disco potato and bumping your compression a tonne and making 350whp with the same or better response than you have now. You also have some sub-optimal hotside parts/setup if your car can only make 256 on a 2560.(assuming you have a built motor and if you don't there's no point to an EFR).
My personal record on a 2560 is 325whp, and recent builds like Ian's car make a comfy responsive 325whp using a really simple motor build that still has a totally stock head and pistons and he has a mediocre manifold and downpipe at best.
So there is plenty of options outside of the EFR. The only reason I'd discourage the EFR is because the cost of going to that setup if you aren't going g to run 400whp. I've built literally dozens on stock motor cars that are making the power you are and a tonne of 300whp cars with pretty basic parts that no one would describe as laggy. At the end of the day it comes down to picking out the weak links and using the few (correctly selected) parts on the build to their full potentially, all working in harmony.

What is your setup right now? Manifolds, headwork, internals, downpipe, exhaust, fuel system, ecu, boost control method etx?

Cheers,
Dann

[The American]

Nb8b (flat top?) intake, avo exhaust manifold and cast down pipe, mild head port/polish, 8.5:1 pistons, Carrillo rods, 2.5" exhaust, ps1000 ecu, MAC valve for ebc, ID1000 injectors, 450lph pump.

[NitroDann]

You could crank the compression, swap to a better flowing manifold and downpipe and exhaust and turn the power up to 300whp with no other changes AND get even better response than now.

Dann

[cookie]

You could crank the compression, swap to a better flowing manifold and downpipe and exhaust and turn the power up to 300whp with no other changes AND get even better response than now.

Dann

Dare I say 11:1 would be a great ratio for e85? I went 9.5 but wanted to run on 95 when stuck in the middle of nowhere.

[NitroDann]

Higher maybe. The last BIG boost MX5 build was 11.2:1, 27psi, 360whp, 1.6L.

Ians flex setup lets him make 270whp very safely on 98 at 10:1 and 325whp on E85.

Dann

[The American]

I think I'd go for a higher compression build if I was starting from scratch. I haven't run mine on anything but e85 since converting. I've already got a built engine that I'm not keen to tear it down unnecessarily.

[NitroDann]

Your loss?

Rattle gun the head off, shave 40 thou off, torque it back on. The cost is nothing except machine work if you do it yourself, you wont need any parts if you have a built engine (metal gasket right? Head studs right?) and now you have extra power per psi and a tonne of extra response.

Dann

[davekmoore]

Watching this with interest as I still have an IHI.

[cookie]

Your loss?

Rattle gun the head off, shave 40 thou off, torque it back on. The cost is nothing except machine work if you do it yourself, you wont need any parts if you have a built engine (metal gasket right? Head studs right?) and now you have extra power per psi and a tonne of extra response.

Dann

Problem is you're messing with the flame fronts etc. No idea if decking a head with e85 isn't an issue as its almost impossible to predet.

[NitroDann]

Its 108 octane, 40 thou will bring it to less than 11:1 and you'll have a tonne of quench area, it's sweet.

[davekmoore]

Your loss?
Rattle gun the head off, shave 40 thou off, torque it back on. The cost is nothing except machine work if you do it yourself, you wont need any parts if you have a built engine (metal gasket right? Head studs right?) and now you have extra power per psi and a tonne of extra response.
Dann

Will this also work with a built SE motor with 9.5 pistons, E85 with Haltech PS1000, flex sensor and everything else properly sorted apart from still having (for the moment) an IHI with 2.5" exhaust - presently running low boost on a conservative tune with 150/170rwkw on 98/E85?

[NitroDann]

Yeah. Of course you'll have to be full time e85 at 10.x:1 + boost.