My new car!
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speedjunkie
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chickenwafer
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Just a little updating...
I'm convinced my primary turbo is shot. It's slow to get up to boost and explains the boost creep I'm experiencing at higher rpm on both turbos. When both turbos are spinning, the exhaust will always take the path of least resistance. The primary turbo has bad bearings, so it's moving slowly, thus the turbine wheel is more resistant to exhaust pressure than the secondary turbine wheel. So more exhaust is routed to the secondary turbo, which it's wastegate can't bypass all the required exhaust pressure, so I over boost.
Matt also let me take his FD for a spin, mainly to try out his short shifter (I want to buy one). His low-end throttle response is INSANE, around 2800rpm or more the turbo is LIT! Stab the throttle the his Defi boost gauge pings 10psi instantly. Mine isn't even close...stab the throttle and boost comes up to 5psi, hangs out for a second, then slowly increases to 10 until transition.
Thanks again Matt for helping with the diagnoses!
So now I have to get new turbos. Options are:
1. Get a set of used twins. They're cheap ($125-$200) and readily available. Problem is they could be just as bad as mine, or great. Who knows? I kinda have to assume any used turbos I get are junk.
2. Get a set of re-manufactured/rebuilt twins from a quality shop. BNR Turbos has been rebuilding twins for the FD for a decade and has quality rebuilds. The turbos look brand new and come with a warranty. They also cost $1100.
3. Set of new CHRA's from BNR. These just replace the CHRA/bearing housings, including both compressor and turbine wheels, so I move everything over (compressor housings, turbine section, oil/coolant lines, etc). Replaces all moving parts. Cost is $700 for both, so the savings are significant over a full set.
4. Pettit Racing offers a full turbo rebuild kit for $500 bucks. This is the cheapest option but also means I have to disassemble, clean, replace, and reassemble everything myself. Rebuilding turbos isn't rocket science or anything, but you have to make sure everything is properly balanced or you will have a free-wheeling 100,000rpm disaster and be out a set of twin turbos! Really, for $200 more I can get the pre-assembled CHRA's from BNR which only requires margin effort to install (remove a few bolts and a big snap ring).
Those are the only options I'm considering now. The JDM 99-Spec twins are too expensive ($2600) and the BNR Stage 3's are also more than I want to spend ($2100).
So that's where I'm at. I'm thinking I'll get a set of used twins on 7club, take my chances expecting nothing. If they're junk, I can use them as a core for a rebuild. Or if they have a good primary and I have a good secondary, I can just swap them into 1 (I've heard of this being common), and I'll still have another set leftover to rebuild later.
Since I plan on running 16-18psi, I don't expect these turbos to last long anyways. 5,000 mile would be great, 10,000 miles would be awesome. I only drive the car 2,000 miles a year anyways or less. Which is why I kinda treat them like brake pads...an expendable wear item, so I don't want to spend 4 digit money fixing them.
I'm convinced my primary turbo is shot. It's slow to get up to boost and explains the boost creep I'm experiencing at higher rpm on both turbos. When both turbos are spinning, the exhaust will always take the path of least resistance. The primary turbo has bad bearings, so it's moving slowly, thus the turbine wheel is more resistant to exhaust pressure than the secondary turbine wheel. So more exhaust is routed to the secondary turbo, which it's wastegate can't bypass all the required exhaust pressure, so I over boost.
Matt also let me take his FD for a spin, mainly to try out his short shifter (I want to buy one). His low-end throttle response is INSANE, around 2800rpm or more the turbo is LIT! Stab the throttle the his Defi boost gauge pings 10psi instantly. Mine isn't even close...stab the throttle and boost comes up to 5psi, hangs out for a second, then slowly increases to 10 until transition.
Thanks again Matt for helping with the diagnoses!
So now I have to get new turbos. Options are:
1. Get a set of used twins. They're cheap ($125-$200) and readily available. Problem is they could be just as bad as mine, or great. Who knows? I kinda have to assume any used turbos I get are junk.
2. Get a set of re-manufactured/rebuilt twins from a quality shop. BNR Turbos has been rebuilding twins for the FD for a decade and has quality rebuilds. The turbos look brand new and come with a warranty. They also cost $1100.
3. Set of new CHRA's from BNR. These just replace the CHRA/bearing housings, including both compressor and turbine wheels, so I move everything over (compressor housings, turbine section, oil/coolant lines, etc). Replaces all moving parts. Cost is $700 for both, so the savings are significant over a full set.
4. Pettit Racing offers a full turbo rebuild kit for $500 bucks. This is the cheapest option but also means I have to disassemble, clean, replace, and reassemble everything myself. Rebuilding turbos isn't rocket science or anything, but you have to make sure everything is properly balanced or you will have a free-wheeling 100,000rpm disaster and be out a set of twin turbos! Really, for $200 more I can get the pre-assembled CHRA's from BNR which only requires margin effort to install (remove a few bolts and a big snap ring).
Those are the only options I'm considering now. The JDM 99-Spec twins are too expensive ($2600) and the BNR Stage 3's are also more than I want to spend ($2100).
So that's where I'm at. I'm thinking I'll get a set of used twins on 7club, take my chances expecting nothing. If they're junk, I can use them as a core for a rebuild. Or if they have a good primary and I have a good secondary, I can just swap them into 1 (I've heard of this being common), and I'll still have another set leftover to rebuild later.
Since I plan on running 16-18psi, I don't expect these turbos to last long anyways. 5,000 mile would be great, 10,000 miles would be awesome. I only drive the car 2,000 miles a year anyways or less. Which is why I kinda treat them like brake pads...an expendable wear item, so I don't want to spend 4 digit money fixing them.
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chickenwafer
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I want to, but I don't think I'm ready to go single just yet. There's a lot more stuff that also needs upgrading. Mainly the clutch. I'll have enough fuel for around 400rwhp.
Besides, when i dump the factory twins, I want to do something a little more...creative. Think compound twin turbos or twin GT30's.
Besides, when i dump the factory twins, I want to do something a little more...creative. Think compound twin turbos or twin GT30's.
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speedjunkie
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Brian used a set of my stock turbos to swap his primary turbo while he was here at the house, so yes it's common...for him at least, since he did that 4 times and an engine rebuild during the trip LOL. HE is the reason I will never go back to twins, for sure now. What a nightmare. I love the response of the twins but it's just not worth the hassle for me.
Simon is doing twin T04Z, I think they're Z anyway. But yeah, it's pretty ballin'. And also a lot more than what you're wanting to spend right now LOL.
Simon is doing twin T04Z, I think they're Z anyway. But yeah, it's pretty ballin'. And also a lot more than what you're wanting to spend right now LOL.
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chickenwafer
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Twin T04Z? That's overkill. I think you mean twin T04E's. He bought Howard Coleman's kit, right?
For a compound charged setup I would run a ball bearing T25 from the primary with GT35R or BW S366XL as the second turbo. 10psi by 2500rpm, then 18psi off the larger secondary turbo, easy 450rwhp with T25-like boost response (as good as the factory sequential twins, without all the complications or less than reliable performance).
I'm actually leaning now to just ditching the twins...it's more effort than reward at this point.
For a compound charged setup I would run a ball bearing T25 from the primary with GT35R or BW S366XL as the second turbo. 10psi by 2500rpm, then 18psi off the larger secondary turbo, easy 450rwhp with T25-like boost response (as good as the factory sequential twins, without all the complications or less than reliable performance).
I'm actually leaning now to just ditching the twins...it's more effort than reward at this point.
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speedjunkie
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chickenwafer
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Alright, I'm 99% going single turbo this spring. I just now need to decide what kind of turbo system I want.
Goals:
1. Quick spool is a must. I don't want to feel like I'm driving a diesel rig and I don't want to always have to downshift 2+ gears to get power. So turbo sizing is critical.
2. Power goals are a conservative 375-400rwhp right now, but the system should be "future proofed" for up to 600rwhp (with supporting mods and possibly a new turbo, obviously). The more modular the system, the better.
I'm debating between a few turbos, and kicking around a twin GT28RS or twin T04E system as well. I'm most leaning towards a new billet Precision PT6262. Quick spool and the turbo is good for 450rwhp or so. Spool should be quicker than a GT35R, which is the benchmark of FD turbos.
Goals:
1. Quick spool is a must. I don't want to feel like I'm driving a diesel rig and I don't want to always have to downshift 2+ gears to get power. So turbo sizing is critical.
2. Power goals are a conservative 375-400rwhp right now, but the system should be "future proofed" for up to 600rwhp (with supporting mods and possibly a new turbo, obviously). The more modular the system, the better.
I'm debating between a few turbos, and kicking around a twin GT28RS or twin T04E system as well. I'm most leaning towards a new billet Precision PT6262. Quick spool and the turbo is good for 450rwhp or so. Spool should be quicker than a GT35R, which is the benchmark of FD turbos.
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speedjunkie
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chickenwafer
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Yeah, the billet 6262 looks like a great option. I'm also looking at the new Garrett GTX3076R with the billet comp wheel.
I had a GT3071R on my RX-8 and I felt it delivered outstanding boost response. Problem was mainly with higher horsepower. By getting the 76R version I get a larger comp and turbine wheel and larger housings. Spool is only moved back by 200rpm if even. But then, add in this turbo now features a billet comp wheel, and that the 13B-REW has much better exhaust flow (due to the exhaust ports and power output) than the 13B-MSP, I bet it will spool a 500+rpm sooner than my old turbo RX-8, plus should support over 450rwhp!
So we're talking an easy 15psi+ by 2700rpm and a potential for 450rwhp. Garrett lists the turbo for 640hp, I'm not sure if that's crank or wheel, however. Because rotaries require more airflow, that number is lower by a factor of at least 15-20%.
The last idea I was kicking around a compound turbo setup. I would have a small t04e mounted on a short runner manifold. This would provide excellent stock seq twin like spool. Then exhaust would flow out of the t04e into a GT42R- excellent top end power. A 10psi TiAL 60mm wastegate would be on the short runner manifold so at once the primary t04e turbo hits 10lbs, the wastegate would open and most exhaust gas would bypass the smaller turbo and flow directly into the 42R.
The intake is on the 42R, then it's compressor feeds the inlet into the smaller turbo. Finally, the compressor discharge on the t04e goes into the intercooler.
Diesels have been doing this years and it produces fantastic results. Recently, Supra's started getting into it in their quest for never ending power. We're talking small turbo spool (t04e) with big turbo top end (GT42R) and virtually no drawbacks.
Problem for me is, besides the system being expensive to fabricate, it's really more geared for high horsepower (think 600rwhp if not more). I don't want that much power (yet, haha) so it's not the best system for me when I can accomplish most of what I want for a lot cheaper and simpler with a single turbo.
I had a GT3071R on my RX-8 and I felt it delivered outstanding boost response. Problem was mainly with higher horsepower. By getting the 76R version I get a larger comp and turbine wheel and larger housings. Spool is only moved back by 200rpm if even. But then, add in this turbo now features a billet comp wheel, and that the 13B-REW has much better exhaust flow (due to the exhaust ports and power output) than the 13B-MSP, I bet it will spool a 500+rpm sooner than my old turbo RX-8, plus should support over 450rwhp!
So we're talking an easy 15psi+ by 2700rpm and a potential for 450rwhp. Garrett lists the turbo for 640hp, I'm not sure if that's crank or wheel, however. Because rotaries require more airflow, that number is lower by a factor of at least 15-20%.
The last idea I was kicking around a compound turbo setup. I would have a small t04e mounted on a short runner manifold. This would provide excellent stock seq twin like spool. Then exhaust would flow out of the t04e into a GT42R- excellent top end power. A 10psi TiAL 60mm wastegate would be on the short runner manifold so at once the primary t04e turbo hits 10lbs, the wastegate would open and most exhaust gas would bypass the smaller turbo and flow directly into the 42R.
The intake is on the 42R, then it's compressor feeds the inlet into the smaller turbo. Finally, the compressor discharge on the t04e goes into the intercooler.
Diesels have been doing this years and it produces fantastic results. Recently, Supra's started getting into it in their quest for never ending power. We're talking small turbo spool (t04e) with big turbo top end (GT42R) and virtually no drawbacks.
Problem for me is, besides the system being expensive to fabricate, it's really more geared for high horsepower (think 600rwhp if not more). I don't want that much power (yet, haha) so it's not the best system for me when I can accomplish most of what I want for a lot cheaper and simpler with a single turbo.
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chickenwafer
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I've made some very small headway in my single turbo build thus far...got a manifold! It's an EBay manifold but not one of the cheapest ones...not sure if it makes any difference...but I received it yesterday and it feels pretty heavy duty. Nice thick walled metal, a 0.50" thick and machined flat flange and it's a true divided twin scroll design as well. Really, it's so cheap, it doesn't matter if it breaks, I can just replace it or fix it for cheap.
The biggest problem with the manifold, however, is the wastegate flange. It's setup for the old-school HKS 50mm 4-bolt square design, which no manufacture uses anymore except for EBay wastegates. An EBay manifold isn't a big deal, but a cheap wastegate can cost you a motor, so I'm not trusting my rotary to a $50 wastegate.
Banzai racing makes a nice adapter to allow you to simply bolt on the adapter to the flange and then hook up a TiAL 44mm v-banded gate to it. But it costs $120 bucks, when I can just chop off the flange myself and weld on the v-band flange for next to nothing. So that's the route I'm going. I measured the pipe and it's approx 47.22mm in diameter so it shouldn't be a problem getting the 44mm v-band flange welded on there.
I'm also still on the fence about which turbo to get...looking over compressor maps I really don't need anything that flows more than 55lbs/min, so I think I'm going to get a Garrett T04E 60trim with a divided twin scroll 0.84A/R housing. This turbo should spool quicker than stock non sequential twins and still should push 400rwhp at high boost. I have a stock port motor anyways so it's not like I'm trying to break any records.
The only other turbo I'm seriously considering is the Garrett T04S 60-1 with the same divided twin scroll 0.84A/R housing. Flows more air (60ish lbs/min) and is roughly the same cost but will spool a few hundred RPM slower.
The biggest problem with the manifold, however, is the wastegate flange. It's setup for the old-school HKS 50mm 4-bolt square design, which no manufacture uses anymore except for EBay wastegates. An EBay manifold isn't a big deal, but a cheap wastegate can cost you a motor, so I'm not trusting my rotary to a $50 wastegate.
Banzai racing makes a nice adapter to allow you to simply bolt on the adapter to the flange and then hook up a TiAL 44mm v-banded gate to it. But it costs $120 bucks, when I can just chop off the flange myself and weld on the v-band flange for next to nothing. So that's the route I'm going. I measured the pipe and it's approx 47.22mm in diameter so it shouldn't be a problem getting the 44mm v-band flange welded on there.
I'm also still on the fence about which turbo to get...looking over compressor maps I really don't need anything that flows more than 55lbs/min, so I think I'm going to get a Garrett T04E 60trim with a divided twin scroll 0.84A/R housing. This turbo should spool quicker than stock non sequential twins and still should push 400rwhp at high boost. I have a stock port motor anyways so it's not like I'm trying to break any records.
The only other turbo I'm seriously considering is the Garrett T04S 60-1 with the same divided twin scroll 0.84A/R housing. Flows more air (60ish lbs/min) and is roughly the same cost but will spool a few hundred RPM slower.
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chickenwafer
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Also...I'm debating pulling the motor right now, but not to rebuild. It can make some of this work easier (i.e. removing all emissions stuff and installing the fuel system) but it's obviously a lot of work to pull the motor. Also, if I pull the motor I "might as well while I'm in there" (famous words of ANY FD owner haha) replace the clutch and do new motor mounts.
One of the main reasons I want to pull the motor is to reseal the oil pan (VERY difficult to do in the car) and fix any other oil leaks, I must have a few. The bottom of the throttle body elbow usually has some oil on it after a long driver...it's probably from the dipstick and PVC issues.
Also, with the motor out, I can more easily clean up stuff in the engine bay. But...this is a lot of a work and I would need to a hoist somehow, either borrowing one or buying one. Just more stuff to think about!
One of the main reasons I want to pull the motor is to reseal the oil pan (VERY difficult to do in the car) and fix any other oil leaks, I must have a few. The bottom of the throttle body elbow usually has some oil on it after a long driver...it's probably from the dipstick and PVC issues.
Also, with the motor out, I can more easily clean up stuff in the engine bay. But...this is a lot of a work and I would need to a hoist somehow, either borrowing one or buying one. Just more stuff to think about!
I may ask to borrow that hoist, Frank. Really need to do the motor mounts in my Miata. Are you using it next weekend? 15th and 16th?
2015 Ironman Silver Veloster Turbo - Bone stock and staying that way
1990 Crystal White Miata - Beater - Bignose 1.6L Swap, Robbins Top w/Glass Window, E-Codes, Air Horns, Brembo Rotors
Former Rides:
2011 Kona Blue Mustang GT 5.0
2009 True Red Mazdaspeed3 GT
2005 Flame Red SRT-4
1990 Crystal White Miata - Beater - Bignose 1.6L Swap, Robbins Top w/Glass Window, E-Codes, Air Horns, Brembo Rotors
Former Rides:
2011 Kona Blue Mustang GT 5.0
2009 True Red Mazdaspeed3 GT
2005 Flame Red SRT-4
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