MR2 Owners Club Forum banner

21 - 40 of 79 Posts

·
Registered
Joined
·
1,540 Posts
Discussion Starter · #22 ·
You're probably not anywhere near 25% drivetrain loss. These modern automatic transmissions aren't like the old slushboxes from back in the day. As much as i'm a solid fan of manual transmissions and would never want to own an automatic i can't say that efficiency is the reason for that anymore...
This is a very good point. And it would mean probably that the power output is being capped by the exhaust. Depending on how the turbo is done, this limitation might be removed entirely. But it still puts the flywheel goal in the range 470-500.

The twin scroll just helps the spool, if you're trying to stay on a budget build there are still options out there. Here's a quick one i can think of for $150: https://www.ebay.com/itm/2006-Ford-Powerstroke-Super-Duty-F-350-6-0L-Garrett-Turbo/142715195743
This is a great find. For $150 there's almost no reason not to go with this, and at least use it to shake things down.
 

·
Registered
Joined
·
1,540 Posts
Discussion Starter · #23 · (Edited)
Have any of you thought of running twin G25 550 turbos .72 AR.
I looked at this yesterday while picking out a twin candidate from the Garrett range. It looked at first glance like it might be better suited as a single turbo for the 2GR. Without doing any detailed calculations my guess it would be slow to spool and late to hit max boost as a twin. The map looks similar to the EFR6258 that I looked at previously.

https://www.turbobygarrett.com/turbobygarrett/turbochargers/g-series-g25-550



I know this is available in reverse rotation which means it is positioned for a V-engine but possibly it would be better for a V8.
 

·
Registered
Joined
·
107 Posts
I looked at this yesterday while picking out a twin candidate from the Garrett range. It looked at first glance like it might be better suited as a single turbo for the 2GR. Without doing any detailed calculations my guess it would be slow to spool and late to hit max boost as a twin. The map looks similar to the EFR6258 that I looked at previously.

https://www.turbobygarrett.com/turbobygarrett/turbochargers/g-series-g25-550



I know this is available in reverse rotation which means it is positioned for a V-engine but possibly it would be better for a V8.
This turbo should spool as quick as the gtx2860 and make more power. The gtx2860 is no mean a slow spooler. 2GRFE (direct injection stuff removed) + twin GTX2860
That is some impressive low end power for a relatively stock V6. My goal is around 500whp pump gas this turbo might be the perfect candidate. Easier to fit into the MR2 engine bay due to its smaller frame design.
 

·
Registered
Joined
·
107 Posts
Sorry, I pulled up an old link as a starting point and i did not realize it was on twin turbo, that explains why it took so long to bring the boost on. here's a single turbo setup that i meant to put show: BorgWarner MatchBot note how high the wastegated flow is, the higher this the more responsive the turbo is because you generally have a bunch of excess exhaust energy for what you're looking to do with it. You can manually sweep through the boost pressure curve to check that you have high wastegate at all intermediate boost settings to make sure of this but at a 9psi setup you can generally be sure that this won't be a problem. when you're doing 15psi plus that's when you can easily have dead spots that prevent you from building boost that high.

I did have to bump up to the 6758 but the 6758 is about the same price and significantly cheaper than the bigger ones. but the airwerks turbos are much cheaper also but they use journal center sections so they don't tend to spool quite as quickly.

With the 2GR i would run the normal headers and put it under the trunk floor. it does complicate oil return plumbing but it greatly simplifies the exhaust and reduces the heat in the engine bay.

Fitting twins in the MR2 engine bay would be doable with more of a log style manifold on each end. there is plenty of room in the rear and the front is tight but doable especially with the small size turbo you'd need for the 1.73L of displacement up there. but keep in mind parallel twins really only help plumbing sometimes and when you need so much boost that a large enough turbo isn't available at a reasonable cost. Sequential twins is where you gain a bunch from twin turbos and those simply aren't needed for this boost level with modern turbos.
With a twin parallel set up, Do you think it's feasible to put the turbos between the engine and the 2 firewalls (cabin firewall and trunk firewall)?
 

·
Registered
Joined
·
1,540 Posts
Discussion Starter · #26 · (Edited)
This turbo should spool as quick as the gtx2860 and make more power. The gtx2860 is no mean a slow spooler. 2GRFE (direct injection stuff removed) + twin GTX2860. That is some impressive low end power for a relatively stock V6. My goal is around 500whp pump gas this turbo might be the perfect candidate. Easier to fit into the MR2 engine bay due to its smaller frame design.
Interested what is that chart you displayed and where does it come from. Looks like another turbo calculator maybe?

PS. we had some previous discussions about the temps on the rear firewall pretty darn hot with the na headers so if you stuff a turbo back there be prepared for some serious heat shielding.
 

·
Registered
Joined
·
107 Posts
Maybe if I fab up a heat shield + DEI turbo blanket (does the blanket even work? If turbo blanket works why no car manufacturer have it on their cars?) + power coat the down pipes.
 

·
Registered
Joined
·
374 Posts
Has anyone ever considered using the stock Ecoboost 3.5L Turbos? (BorgWarner K03)

Seems like if they reasonably fit between the firewalls then it would solve the plumbing/heat issues of running a turbo above the transmission and solve the oil drainage / sump issue of having it under the trunk. I just don't know them well enough to place them on the candidate chart. I can see doing twins being a hassle but it hard to get away from any complex solutions for placing a turbo in a 2GR MR2.
 

·
Premium Member
Joined
·
3,647 Posts
I haven't looked at maps for it but the turbos are designed for a motor exactly the same size with a similar rev-range. as long as the power range is about what you're looking for it should be a great fitment. Stock turbos are always sized to light off quickly so you're very likely going to get great bottom end also.
 

·
Registered
Joined
·
374 Posts
In your professional opinion, would they physically fit between each bank and the firewalls, more specifically in the rear above the interm. shaft?
 

·
Premium Member
Joined
·
3,647 Posts
The issue you're going to have is the ecoboost has integrated exhaust manifolds. You'll need to make a manifold that bolts to the engine and keep it really low profile.

It won't be easy but on an MR2 without A/C i bet you can get it to fit if you try hard enough. I suspect it would be significantly easier to go over the trans or under the trunk though.
 

·
Registered
Joined
·
1,540 Posts
Discussion Starter · #32 ·
Has anyone ever considered using the stock Ecoboost 3.5L Turbos? (BorgWarner K03)
I don't know about these K03 but someone else asked about the GT1548 twins from the same engine which I have to assume are sized somewhat similar and it didn't look that promising from the maps because the maximum air flow caps at 400bhp.

http://www.mr2oc.com/6764946-post17.html

The other thing to consider is setting fire to the rear firewall. As reported elsewhere it gets mighty hot with just NA headers.
 

·
Registered
Joined
·
374 Posts
I'd be more concerned with melting connectors/wiring and rubber lines with running header pipes joining to the turbo over the transmission and a larger downpipe also finding it's way down again. A lot more fabrication is required to do also which brings up the cost in material.

I'm sure with enough care in wrapping, ceramic coating, tucking and shielding it can be done. The same can be done with the rear firewall just to a lesser extent since the only real vulnerable part is the firewall sheet metal.

With twins the header would pretty much have to a log style manifold just to make it as compact as possible. The front side is already protected against the heat, the rear could be shielded relatively easily. It's really more of a concern of will it actually fit in that space when it's all said and done. That is where I have no idea, I have a 2GR and I have a MR2, I just don't have a 2GR in an MR2 (yet) so I'm 100% clueless as to what's the space restrictions.

If I understand correctly, the K03 (from the F-150's) flows more than the GT1548 (transvers version). By how much, I don't know but it might be worth looking into. If they can keep 8-9 PSI up to the redline, it would satisfy a lot of people's goal in boosting on a stock bottom end.
 

·
Registered
Joined
·
917 Posts
IMO, heat shielding of wires etc. with a custom turbo setup is the least of your worries. That takes maybe $100 of materials and a few hours to go through, versus the probably 100-200 hrs of custom fabrication you're looking at to do a turbo setup.


IMO, I would not want to deal with a small twin setup in an MR2 engine bay. Keep in mind that fitting the turbos is only half the battle. You still have to get a downpipe, compressor inlet and compressor outlet pipe to the turbo as well! I believe it could be done, but it would likely be really tight in a few places, which is going to make the fab work that much harder.


I also disagree with many of the compressor maps chosen here - the goal is not to have the engine be at a really high compressor efficiency at redline. That'll just give you a laggy turbo. The EFR 9180 is a ~800-900 rwhp turbo. Running it at 450-500 rwhp on a 3.5L is going to be pretty laggy for no good reason. An EFR 7670 or EFR 8374 is more than enough for a stock internal 2GR. The 8374 can do about 700 rwhp with the wick turned up, so it will not be stressed at all for 500 rwhp.


I'm a big fan of the EFRs, they drive great compared to a comparable Garrett. The TiAl turbine wheels make them drive like a one or two step smaller Garrett on the street, and it really changes the personality of the car for the better. Everything is integrated into the turbo, so just find a good spot to mount it over the trans and go from there with minimal plumbing work (compared to twins).


I'm not a huge fan of any of Garrett's stuff, as you're either looking at a new compressor with an ancient turbine (GTX line) or a new compressor and turbine design in heavy inconel for way more than an EFR actually goes for. Then you still have a high moment of inertia turbine to slug around.
 

·
Registered
Joined
·
917 Posts
EFRs come with turbine wheels made of TiAl (Gamma phase titanium aluminide). TiAl has roughly half the density of inconel (going from memory). It was also used for the turbine wheel for the JDM Lancer Evo VI RS, but the Borg Warner EFR line is the first aftermarket lineup that uses TiAl turbine wheels.


This has nothing to do with the aftermarket brand Tial if that's what you're asking.
 

·
Registered
Joined
·
2 Posts
First things first, I am no where near as knowledgeable as everyone posting here. I also know that this doesn't make 500hp...

BUT wouldn't the "87S72 (AirWerks S300SX-E) 13009097006 13009097047" be a much better fit? From what I see it would give you a much more broad power band over a much larger RPM range? Don't get me wrong, 500hp definitely has Big D Energy, but if you only make power between 5k-7k rpm then you might as well make a kswap drag car. But if you are looking to keep the MR2 as a canyon carver like it is designed for. Wouldn't this be a better option?
 

·
Premium Member
Joined
·
13,333 Posts
First things first, I am no where near as knowledgeable as everyone posting here. I also know that this doesn't make 500hp...

BUT wouldn't the "87S72 (AirWerks S300SX-E) 13009097006 13009097047" be a much better fit? From what I see it would give you a much more broad power band over a much larger RPM range? Don't get me wrong, 500hp definitely has Big D Energy, but if you only make power between 5k-7k rpm then you might as well make a kswap drag car. But if you are looking to keep the MR2 as a canyon carver like it is designed for. Wouldn't this be a better option?
If you are looking to make it a canyon carver, leave the 2GR NA, it's perfect as it is.
 
  • Like
Reactions: sarnodude

·
Registered
Joined
·
48 Posts
First things first, I am no where near as knowledgeable as everyone posting here. I also know that this doesn't make 500hp...



BUT wouldn't the "87S72 (AirWerks S300SX-E) 13009097006 13009097047" be a much better fit? From what I see it would give you a much more broad power band over a much larger RPM range? Don't get me wrong, 500hp definitely has Big D Energy, but if you only make power between 5k-7k rpm then you might as well make a kswap drag car. But if you are looking to keep the MR2 as a canyon carver like it is designed for. Wouldn't this be a better option?
Since that part number doesn't have the hotside included, what would anyone with it?

Sent from my SM-G892A using Tapatalk
 
21 - 40 of 79 Posts
Top