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I'm starting to piece together a plan for swapping my 94 FD from factory twins to a single turbo. I'm having a bit of difficulty selecting a turbo and the shop I'm having do the work is suggesting what seem to be older turbos that are a bit laggy. I've been looking mostly at the EFR 8374 or EFR 7670 turbo setups from either Turblown or IR Performance with an EWG (mostly because of boost creep concerns), the shop building the car is leaning towards a GT35R or HKS GTIII 4R turbo (https://www.hksusa.com/products/14020/AZ003/3557).
The engine is going to be rebuilt at the time of the single turbo conversion, street ported and pinned. The fuel system (RP fuel pump, fuel rail, new 550cc OEM primary injectors and 2200cc secondary injectors) has already been replaced in anticipation of going single turbo. Its unclear if I'll need to change out the ignition to IGN-1A coils but I think that may also be part of their plan. The goal is a quick spool, 350-400whp and have it as reliable as possible. There is no budget for the build, I just want what is best but I'm having a hard time figuring out what "best" really is.
For the record, I've had nothing but great experiences with this shop and don't question the quality of their work or knowledge base at all. I am just looking to make sure I am going with the best setup possible before I start writing checks. Is there something that I'm fundamentally missing, or is the EFR turbo a better fit for what I'm looking to do?
Thanks in advance, I'm sure I'll learn a lot from this. Or get roasted for being an idiot.
Edit - It might be worth noting the car is RHD, not sure if that limits me much from a fitment standpoint.
EFR 8374 sounds like a perfect fit for what you want.
For best response without boost creep do external wastegate and 3.5-4" downpipe and a large inlet pipe to a velocity stack and a long air filter.
May have to plan IC and radiator positions around the air filter.
I had the EFR 7670 @420rwhp/420rwtq and I would describe it as the best 300-350rwhp turbo you could choose.
The most important thing of making any part selection is what will the car be used for. Just picking the latest and greatest thing without considering the intention of its use is a poor way of decision making.
Also keep in mind simply because something is older, it doesn't necessarily make it obsolete. It simply means its older. The gt35 has been the go to turbo for a VERY long time and for good reason. Theres nothing wrong with it.
Pinning the motor is not necessary or useful for that power level. 8374 will spool better than anything else for that power goal. Boost creep shouldn't be an issue as long as you run 1 bar or more.
Keep in mind, Turblown / Turbosource is way way behind on deliveries. I got the last parts of my kit a full 7 months after ordering and paying.
Lots of replies... thanks guys. I really appreciate the discourse.
Originally Posted by BLUE TII
EFR 8374 sounds like a perfect fit for what you want.
For best response without boost creep do external wastegate and 3.5-4" downpipe and a large inlet pipe to a velocity stack and a long air filter.
May have to plan IC and radiator positions around the air filter.
I had the EFR 7670 @420rwhp/420rwtq and I would describe it as the best 300-350rwhp turbo you could choose.
Good point regarding IC...I'm planning on a Greddy V mount and I did notice that the air filter would be awful close to the back of it with the Turblown kit. I'm sure plenty of people have worked around it though and I'm not opposed to copying what works.
Originally Posted by cewrx7r1
If you are thinking about a GT3582R, get the Force Performance upgrade billet compressor wheel which flows more than the GTX3582R and spools faster.
It is called: FP HTA GT3582R, choose the turbine AR for your needs. I run the 1.06 turbine.
Will check it out, thanks. I'm not opposed to at GT35 if it's my best option so this could be a good fit if I go that way.
Originally Posted by TeamRX8
if a shop is suggesting using a 20+ yo turbo configuration then get a new shop.
if you’re considering a Garrett turbo then the newest G-Series line is what you should be looking at.
Logistically, this is easier said than done. I'd agree with you if this was an LS powered car and I'd be tripping over well known shops in Texas left and right.
If it absolutely has to go somewhere else that's fine I guess but it's certainly not ideal. I don't expect that to actually be the case though.
It's always been easier to take a ride a few miles down the highway and work through things with people than do the back and forth emails and phone calls. I've also had nothing but good experiences with this shop to date and that is worth something to me as well.
The manifold will fit... turbo would need to check but the dimensions are listed as shouldn't be too hard for me to figure out. Thanks.
Originally Posted by cr-rex
The most important thing of making any part selection is what will the car be used for. Just picking the latest and greatest thing without considering the intention of its use is a poor way of decision making.
Also keep in mind simply because something is older, it doesn't necessarily make it obsolete. It simply means its older. The gt35 has been the go to turbo for a VERY long time and for good reason. Theres nothing wrong with it.
Anyway...... what is your intention with the car?
I don't have a strong disposition towards latest and greatest just for the sake of it being newer but if it is objectively better it is what I lean towards. What is it that makes the GT35R the go to option for these cars? Is it that they were the best available at one point in time or that they're still the best available as of 2022?
Full disclosure: The only car I've driven with GT35R was a Subaru owned by friend and the power band sucked, which is what gives me a lot of pause here.
My car is a regular street car, nothing more. Has never seen a track since I've owned it and probably never will, the most I've ever considered was doing a few autocross events but even then it would still be 99% a weekend car I like to toss around some of the curvy roads near my house.
Originally Posted by mr2peak
Pinning the motor is not necessary or useful for that power level. 8374 will spool better than anything else for that power goal. Boost creep shouldn't be an issue as long as you run 1 bar or more.
Keep in mind, Turblown / Turbosource is way way behind on deliveries. I got the last parts of my kit a full 7 months after ordering and paying.
The thought to pin the engine is more a matter of "future proofing" than anything else if I decide years down the line that I want to make more power.
And yikes, 7 months is a long lead time. Their website lists a backorder til late September but small scale manufacturing almost always comes in behind schedule in other aspects of my life so I wouldn't be shocked if its much longer. Fortunately, time is on my side and I'm trying to plan now then execute within the next few months when parts are available/get delivered. What are your overall impressions on the parts themselves? What is good, what could be better? Etc..
you do err; the newer turbos are so much more efficient and to simply wave it off that way only demonstrates a lack of understanding of how to optimize performance while avoiding the dreaded zoom-zoom-boom.
Yet those words are not so much just for yourself. As with all wisdom; it’s for those with the eye to see and know, along with the ear to hear and perceive, the truth of it.
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And yikes, 7 months is a long lead time. Their website lists a backorder til late September but small scale manufacturing almost always comes in behind schedule in other aspects of my life so I wouldn't be shocked if its much longer. Fortunately, time is on my side and I'm trying to plan now then execute within the next few months when parts are available/get delivered. What are your overall impressions on the parts themselves? What is good, what could be better? Etc..
I waited a long time, and when it did arrive, it wasn't complete. Had to ask them to send me all the missing parts. I still don't have a proper oil return, they were "out of the gaskets" and "didn't have the right fittings". I'm praying my downpipe fits. Overall the manifold is nice, rest of the kit is some oil lines, water lines, hardware, not much to it really. Hoping it performs well so it's worth the trouble.
Oh and they told me 2 months when ordering, and then went silent on me for a while
I have the exact build you are planning done by the shop you are likely working with. Both turbos work where the EFR is going to be optimal performance overall and the Garrett is going to save some money. You said you have no limits on the build so the choice is obvious but if you want to save some money and are willing to give up some turbo response then the Garrett will work.
If they haven't already discussed it with you, they have built the exact same thing you are wanting on the exact same car(RHD) so I would be surprised if you have already had this discussion with them and are questioning fitment. If you aren't already on their calendar then waiting for parts isn't a deal breaker. I don't regret my decision on parts used and enjoy the car for the street and track. Just know, those screamer pipes are going to be loud and being RHD you get to deal with all those noises even more.
I have the exact build you are planning done by the shop you are likely working with. Both turbos work where the EFR is going to be optimal performance overall and the Garrett is going to save some money. You said you have no limits on the build so the choice is obvious but if you want to save some money and are willing to give up some turbo response then the Garrett will work.
If they haven't already discussed it with you, they have built the exact same thing you are wanting on the exact same car(RHD) so I would be surprised if you have already had this discussion with them and are questioning fitment. If you aren't already on their calendar then waiting for parts isn't a deal breaker. I don't regret my decision on parts used and enjoy the car for the street and track. Just know, those screamer pipes are going to be loud and being RHD you get to deal with all those noises even more.
It's almost certainly the same shop and I've had this conversation with them twice now so that makes this even more confusing. Going to send you a DM.
Screamer pipes are going to be rough and I'm not thrilled about it but I'd prefer to avoid an IWG so I'm sure I'll just have to live with it.
WGs have been plumbed in with the long cast manifold on rhd, diameter of the downpipe might determine the fabrication difficulty. Here's one extreme example of screamers around 5:50 - that could have been plumbed instead.
Why do you need to avoid IWG? The boost creep issues are mostly overstated, as long as you're happy running 14psi+ you shouldn't have a problem. It's a really simple setup. IRP says his 8374 setup will hold lower boost than the Turbosource kit, it maybe worth looking into that. EWG only makes sense if you want to run super low boost for whatever reason, or if you want to max out a turbo. If your goals are near 400whp, 8374 IWG is proven.
Why do you need to avoid IWG? The boost creep issues are mostly overstated, as long as you're happy running 14psi+ you shouldn't have a problem. It's a really simple setup. IRP says his 8374 setup will hold lower boost than the Turbosource kit, it maybe worth looking into that. EWG only makes sense if you want to run super low boost for whatever reason, or if you want to max out a turbo. If your goals are near 400whp, 8374 IWG is proven.
Boost creep is the concern, even if mostly overstated I see it as an unnecessary risk to take.
Another 347 option appears to have raised it's head over here recently https://golebysparts.au/products/art...ld-to-suit-13b Love short runner manifolds, even if fitment is a pain, wastegate path divider is interesting.
I have customers ask me this question all the time and the answer is as everyone has stated. The EFR 8374 is going to do everything you want in the best possible way. Old tech works and in 2023 old tech can identify as new tech however if my grandma had ***** I would call her grandad, Much is the same with Turbos 20 + years of development wasnt for nothing alot of tuners favour the old stuff because its what they know but not necassarily the best. The G series from Garrett is also a great choice with a ton of options available.
I dont like the wastegate runner merge nor the collector merge.
The near vertical (instead of usual horizontal) turbo flange is a nice idea for better flow into the turbo (less bends).
I have been wishing Turblown had used a vertical T4 divided flange on their long runner cast SS manifold to eliminate the 90 deg bend just before the turbo flange.
Reasons they didnt could be you have to re-clock your turbo hotside for the oil drain orientation or they didnt think of it.
I dont like the wastegate runner merge nor the collector merge.
The near vertical (instead of usual horizontal) turbo flange is a nice idea for better flow into the turbo (less bends).
I have been wishing Turblown had used a vertical T4 divided flange on their long runner cast SS manifold to eliminate the 90 deg bend just before the turbo flange.
Reasons they didnt could be you have to re-clock your turbo hot side for the oil drain orientation or they didnt think of it.
Not a professional fabricator by any stretch but my only concern looking at it was the wastegate runner orientation as well, I'm just trying to determine if I would have any boost creep issues with a manifold like this at high power levels 450+, especially with a single wastegate setup. He offers selections for a 60mm gate so I'm not sure if that involves larger diameter tubing as well but other than that I've heard nothing but good things and high-quality remarks from Vinny fabs stuff.
On the other hand this is the HKS FD RX-7 T04Z V-band manifold.
I still dont love the WG merge, but the WG runner is huge.
It is equal length and primaries have a good merge angle. If you want a shorty V-band manifold its pretry good.
The V-band exhaust housing will really only start to have any performance advantage over divided T4 when you use a long runner manifold.
The HKS T04Z was switched to V-band for reliability on the circuit (wont blow out turbo flange gaskets) while retaining their old T04Z turbo placement.
Twins Turbo Motorsports (Jack Mardikian time attack car) specialized in long runner V-band manifolds for the FD and achieved 1:1 boost to emp pressures for circuit reliability (engine health).
This is from WG priority OVER turbo priority and pre-turbine exhaust expansion through long runners.
There is a long runner V-band manifold on ebay right now for $220, but it is lacking the 90deg wastegate and turbo merge piece . It is also a bit shorter/less bends as it is top mount turbo, not bottom mount as Twins Turbos pic above.
Appreciate all the info and insight, I wasn't really aware of when the performance benefits of the vband setup came into play so that is definitely interesting. For reference I want to upgrade to a vband setup from my non-divided T4 manifold for 1)gasket reliability/peace of mind, 2)ease of maintenance/removal 3)I have an issue right now where my compressor housing is touching the heater core hardline on my RHD car and I could use a little more clearance and adjustability with the vband housing 4)also want to upgrade to a 60mm waste gate hence why is as interested in the Vinny Fab option.
