Returning to turbos and ICs after 20 years

[AydinZ71]

Sorry all for the repeat posts! Looks like I made the mistake of including punctuation (incorrectly) in the subject line. Post is below once I confirm I did this right  

[AydinZ71]

Hi all! this post is about my L28et powered 71’. Some quick specs to start below. I purchased her stock in 2002 when I was 16, and had her mostly done by 18. I sold her to a great guy un michigan 5 years ago when I moved to Florida for a job. Since then, I was divorced and returned to California with my kids and struck a deal with the new owner recently to buy her back. I’m preparing for her return this Spring, and have already started some part purchases since.

 

how she sits today:

- L28et with JE forged pistons, overboard 1mm

- stock P90a head with hydraulic lifters 

-stock manifolds and downpipe 

- SDS EFI & 450cc 75’ MB Bosch injectors 

- T3/T4 super 60 trim turbo 

- single Supra IV core IC & 2.5” steel plumbing

- HKS racing 1” bore BOV

- 280zx NA 5-speed

- R200 3.7 open diff from a Z31 

 

parts I have purchased for her return: 

- Protuners custom intake manifold, TB, exhaust manifold and downpipe. 
- Wlad’s super 8.8 rear-end kit and CV’s

- 15’ mustang GT 3.31 LSD diff. 
- going to be using a P90a head with solid lifters off the SCCA race car. Will have it ported, polished, valves deshrowded, and still looking for a turbo cam to extend my peak torque to a higher RPM. As most turbo L28’s, she starts dropping off early at 4500-5000rpm 

 

im delving back into turbo and IC purchases and noticed a lot has changed! For my torque goal of 400ft-lbs, I ran Garett’s turbo calculator online and it seems the most efficient and appropriate turbo for my application is a GT25 550. yeah... that’s where I started LOL. That’s how little I know about the current market. It also seems insanely expensive at $2,000! Spearco was also the leading manufacturer of IC’s at the time, but no idea who makes quality cores now. 

 

id love to hear your choice of a turbo and IC for a budget of $1,000 or less for the turbo and $750 for the assembled IC core. I can manage the plumbing. If you feel that budget is too small, I respect that and would love to understand why something more expensive is worthwhile! 

 

[rossman]

My $0.02:

 

1. Your gearbox is going to be a weak link in the drivetrain soon.  You should consider upgrading to a heavier duty gearbox. There used to be an easy swap for the z32 gearbox but I don't think anyone is selling adapters anymore.

 

2.  Forget about getting a "turbo" cam and just get a good street cam with enough lift (.4"+) to improve flow thru the head. Check out Church of the L on Facebook.  There is a guy who goes by Bonk (I believe) who, from what I have read, sells good, custom regrinds - just tell him what you want and he will recommend one.

 

3. Your budget for a new, modern, turbo is too low in my opinion, double it. If I were buying new I would be looking at the 2nd generation GTX35 line of turbos with a .86 A/R turbine.  I have a first generation GT3576R with a .63 A/R turbine. Boost is pretty much all in at 3.5K but it falls off too early.  A .82 turbine should get me closer to the sweet spot with my current turbo.  A newer generation turbo would give me more low and top end and is an all-round more efficient turbo.

 

4.  For IC, the newer cheap intercoolers seem to be good enough for most people. I have a Godspeed intercooler installed now that I believe is too small. It get's heat soaked quickly.  To fix that and help simplify the install, I have a a larger, 3" thick Mishimoto unit waiting on me to get off my butt and install.

 

Edited December 16, 2020 by rossman

[Zetsaz]

21 hours ago, rossman said:

My $0.02:

 

1. Your gearbox is going to be a weak link in the drivetrain soon.  You should consider upgrading to a heavier duty gearbox. There used to be an easy swap for the z32 gearbox but I don't think anyone is selling adapters anymore.

 

2.  Forget about getting a "turbo" cam and just get a good street cam with enough lift (.4"+) to improve flow thru the head. Check out Church of the L on Facebook.  There is a guy who goes by Bonk (I believe) who, from what I have read, sells good, custom regrinds - just tell him what you want and he will recommend one.

 

3. Your budget for a new, modern, turbo is too low in my opinion, double it. If I were buying new I would be looking at the 2nd generation GTX35 line of turbos with a .86 A/R turbine.  I have a first generation GT3576R with a .63 A/R turbine. Boost is pretty much all in at 3.5K but it falls off too early.  A .82 turbine should get me closer to the sweet spot with my current turbo.  A newer generation turbo would give me more low and top end and is an all-round more efficient turbo.

 

4.  For IC, the newer cheap intercoolers seem to be good enough for most people. I have a Godspeed intercooler installed now that I believe is too small. It get's heat soaked quickly.  To fix that and help simplify the install, I have a a larger, 3" thick Mishimoto unit waiting on me to get off my butt and install.

 

 

Steve Bonk is your man on the cams.

 

GT3076R is what I've been recommended as far turbos, and will likely never be too small short of a lot of work on your head and frankly excessive goals for an L series if you're still running a zx trans. The expense of a good modern turbo, intercooler, having to upgrade my flywheel/clutch/trans, then the associated mounts, is part of why i've reconsidered a swap. for now my stock block running MS3x is more than fun enough to just cruise around in.

[AydinZ71]

On 12/15/2020 at 9:04 PM, rossman said:

My $0.02:

 

1. Your gearbox is going to be a weak link in the drivetrain soon.  You should consider upgrading to a heavier duty gearbox. There used to be an easy swap for the z32 gearbox but I don't think anyone is selling adapters anymore.

 

2.  Forget about getting a "turbo" cam and just get a good street cam with enough lift (.4"+) to improve flow thru the head. Check out Church of the L on Facebook.  There is a guy who goes by Bonk (I believe) who, from what I have read, sells good, custom regrinds - just tell him what you want and he will recommend one.

 

3. Your budget for a new, modern, turbo is too low in my opinion, double it. If I were buying new I would be looking at the 2nd generation GTX35 line of turbos with a .86 A/R turbine.  I have a first generation GT3576R with a .63 A/R turbine. Boost is pretty much all in at 3.5K but it falls off too early.  A .82 turbine should get me closer to the sweet spot with my current turbo.  A newer generation turbo would give me more low and top end and is an all-round more efficient turbo.

 

4.  For IC, the newer cheap intercoolers seem to be good enough for most people. I have a Godspeed intercooler installed now that I believe is too small. It get's heat soaked quickly.  To fix that and help simplify the install, I have a a larger, 3" thick Mishimoto unit waiting on me to get off my butt and install.

 

1) I agree on the gearbox limitation! I’m looking into the new bellhousing conversion to use the 350z trans that Derek has prepared. Open to other suggestions! 
 

2) thanks for the tip! I will message him.

 

3) according to Garrett, the GT25 550 is the most efficient turbo for my application, settling near 80% at full boost. Impressive! I would save quite a bit going to a GT3071. I am attaching the map overlays from Garett’s website for reference. Clearly I need to revisit my budget. What are all these turbo’s out there for $500? Are they all junk? 
 

4) mishimoto seems to have a good following, but I have no first-hand experience. Even their largest universal unit seems to only be $275. No idea which IC manufacturers are better than others, but this is certainly a place worth investing. 
 

thanks again for your reply! 

[AydinZ71]

Here are the maps 

[AydinZ71]

21 hours ago, Zetsaz said:

 

Steve Bonk is your man on the cams.

 

GT3076R is what I've been recommended as far turbos, and will likely never be too small short of a lot of work on your head and frankly excessive goals for an L series if you're still running a zx trans. The expense of a good modern turbo, intercooler, having to upgrade my flywheel/clutch/trans, then the associated mounts, is part of why i've reconsidered a swap. for now my stock block running MS3x is more than fun enough to just cruise around in.

I will definitely contact Steve bonk, thanks! 
 

Il look into that specific turbo and check the map. I agree my trans is the weak link. Any recommended swaps?

 

i have looked at complete engine Swaps too, but since I can do everything I’m describing without pulling my existing block it’s pretty tempting to just keep going. My thought is once the block blows or wears out, il look into a VQ37 or even VR swap. 
 

all additions to the existing engine are pretty affordable, except the turbo replacement itself. 

[Zetsaz]

Any turbo from a reputable brand is gonna start at around $900-$1k for anything in modern designs, and more like $1.5k purchase price with your options. $500 is still the land of Chinese manufacturing, though at those costs, you're probably buying something that will likely work well, just not as well proven as a reputable brand. A $500 chinese turbo is probably completely usable for most people, and a HUGE upgrade in quality from the $100-200 offerings on ebay. 

 

You can probably find a new T3/T4 hybrid turbo from a reputable seller for around $800 with better specs than yours. Perfectly usable, but probably not much of an upgrade from yours if you're looking for latest tech. 

 

Your gear ratios are pretty low at 3.31. Might be sluggish. 280z stock was 3.54, which is actually roughly what the 350z has. If you're making decent power it might work well with the tight gearing of the CD009 but that still seems low to me. Others with more experience can chime in, but a lot of peopel prefer the 3.54. Highest I've seen on a turbo L series for the streat was 3.9 like mine from the "Medusa" Z.

[AydinZ71]

18 minutes ago, Zetsaz said:

Any turbo from a reputable brand is gonna start at around $900-$1k for anything in modern designs, and more like $1.5k purchase price with your options. $500 is still the land of Chinese manufacturing, though at those costs, you're probably buying something that will likely work well, just not as well proven as a reputable brand. A $500 chinese turbo is probably completely usable for most people, and a HUGE upgrade in quality from the $100-200 offerings on ebay. 

 

You can probably find a new T3/T4 hybrid turbo from a reputable seller for around $800 with better specs than yours. Perfectly usable, but probably not much of an upgrade from yours if you're looking for latest tech. 

 

Your gear ratios are pretty low at 3.31. Might be sluggish. 280z stock was 3.54, which is actually roughly what the 350z has. If you're making decent power it might work well with the tight gearing of the CD009 but that still seems low to me. Others with more experience can chime in, but a lot of peopel prefer the 3.54. Highest I've seen on a turbo L series for the streat was 3.9 like mine from the "Medusa" Z.

thanks for the Info. I’m just ignorant of the marketplace. When I had the stock T3 rebuilt into the T3/T4, there weren’t any ultra cheap knockoffs around. It’s helpful to know the $500 range are Chinese knockoffs and not necessarily reputable. There are just many more options on the market today than I was accustomed to in the early 2000’s. 
 

I definitely hear you on the gear ratios. If the 3.31 drags out too long between shifts, I could always buy another super 8.8 in a higher ratio. I intentionally wanted to try a lower geared rear end this time around, as my 3.7 had me shifting quite a bit more than I liked. 

[Zetsaz]

1 hour ago, AydinZ71 said:

thanks for the Info. I’m just ignorant of the marketplace. When I had the stock T3 rebuilt into the T3/T4, there weren’t any ultra cheap knockoffs around. It’s helpful to know the $500 range are Chinese knockoffs and not necessarily reputable. There are just many more options on the market today than I was accustomed to in the early 2000’s. 
 

I definitely hear you on the gear ratios. If the 3.31 drags out too long between shifts, I could always buy another super 8.8 in a higher ratio. I intentionally wanted to try a lower geared rear end this time around, as my 3.7 had me shifting quite a bit more than I liked. 

 

I'm at a 3.9 but I'm NA so it's fine. It's the only thing keeping the old engine fun right now alongside megasquirt making it far more driveable and clean burning than before. 

 

I know some people have had good success with CX Racing turbos, but honestly that's literally as cheap as I'd dare go. From a lot of reading, and one friend's personal experience, that's kind of the breakaway line in quality. Any lower and it's not worth your money. CX is barely manageable. If for some reason you REALLY don't want to spend the money on a proper turbo (which I think is the only right way to do it), I would look into what brands some of the cheap LS swap guys are running. Seems like they'd be the most in the know on what holds up for a low cost.

[Bernardd]

You might want to check out Jeff Priddy's dyno runs.  He built a nice setup with an old school t04e/t3 turbo.  He made over 400lb/ft of torque by 4krpm and 350hp.  He's outlined his parts as well.  

[AydinZ71]

4 hours ago, Bernardd said:

You might want to check out Jeff Priddy's dyno runs.  He built a nice setup with an old school t04e/t3 turbo.  He made over 400lb/ft of torque by 4krpm and 350hp.  He's outlined his parts as well.  

thank you! I will search his name  

[rossman]

For what it's worth, I run a 3.7 with a z32 gearbox.  That is the same gearing the stock z32tt ran.  It seems ideal for me for mostly city/suburb driving. At 60 mph in 5th gear the engine is quite happy right around 2300 rpm. It's probably just me but 6 speeds have one too many gears but that may be because I'm just getting lazy in my old age, lol!  On a side note, I went to Garrett's site to check out their gtx30 compressor maps and compared it the gtx35.  They look identical, which seems a bit odd to me so I inquired to see if there is a mistake.

[AydinZ71]

33 minutes ago, rossman said:

For what it's worth, I run a 3.7 with a z32 gearbox.  That is the same gearing the stock z32tt ran.  It seems ideal for me for mostly city/suburb driving. At 60 mph in 5th gear the engine is quite happy right around 2300 rpm. It's probably just me but 6 speeds have one too many gears but that may be because I'm just getting lazy in my old age, lol!  On a side note, I went to Garrett's site to check out their gtx30 compressor maps and compared it the gtx35.  They look identical, which seems a bit odd to me so I inquired to see if there is a mistake.

ahhh very cool! Well I feel like my options are pretty limited on gearboxes. For a car with this much torque, I also dont feel I “need” a 6-speed, but I don’t know of any other options at the moment besides the new bellhousing Derek is casting for the 350z trans. Any other ideas come to mind? 

[rossman]

Yah, I don't think anyone offers the z32 adapters anymore. It's too bad because the gearboxes are still available new, relatively cheap and the adapters are inexpensive to make.

[boosted300]

Goldmines of information in here.

 

 

[AydinZ71]

On 12/18/2020 at 7:00 PM, rossman said:

Yah, I don't think anyone offers the z32 adapters anymore. It's too bad because the gearboxes are still available new, relatively cheap and the adapters are inexpensive to make.

yeah it’s a shame

I was looking at the S130 T5’s but from what I read they are not ideal either. They are rare now and at least $800 a pop. I’d still need a custom driveshaft, and they would not handle the torque of the CD009. Looks like il be putting in an order for that bellhousing. 
 

On the other hand, I could pull a CD009 from a junkyard myself. And have quite a bit. 

[rossman]

As @Zetsaz is also experiencing, the cost of upgrading the Datsun L6 is quite expensive and the low bang/buck makes most people consider other alternatives.  I was lucky enough to get in the game when it was still fairly inexpensive to pull off using old school Nissan parts. 

 

Regarding the CD009, I will say that it shifts really well, probably better than the z32 ever did. I'm sure you will be happy with it after the pain in your wallet fades.

[AydinZ71]

5 hours ago, rossman said:

As @Zetsaz is also experiencing, the cost of upgrading the Datsun L6 is quite expensive and the low bang/buck makes most people consider other alternatives.  I was lucky enough to get in the game when it was still fairly inexpensive to pull off using old school Nissan parts. 

 

Regarding the CD009, I will say that it shifts really well, probably better than the z32 ever did. I'm sure you will be happy with it after the pain in your wallet fades.

 

Agreed. If i was starting from scratch, I would go with the VQ37 or VR swap. The LS is too much displacement for me (just personal preference). Given what I am starting with, my plan is to wear-out the L28et setup, then consider selling the bones. I came to this conclusion when considering the costs, but with the modern turbo im getting close to the cost of a VQ swap. Still, its not entirely a cost consideration since I can accomplish everything I described above without pulling my block which will save me quite a bit of time and effort. Thinking this over, i might just keep my stock cam and keep her closer to the 350hp mark. The current clutch will hold the torque, so it might just give me more time on the ZX trans. I need a new turbo anyway, and I was pleased with the Protunerz price on the complete manifold setup.