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T3/T4 Turbo that spools like stock?

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I've been reading up on turbos for over 6 hours between today and yesterday ūü§™ haha and have gone from zero knowledge to some knowledge. I am a big proponent of "buy once, cry once" methodology and while I am updating a bunch of other stuff on the Z, I am wondering if I should just knock out the turbo as well.

 

HP Goal: Reliable 260hp-290hp for application that is 99% street

Torque Goal: 300-310ft/lbs

Spool RPM: 2400 RPM start with full boost by ~3000 RPM (similar to stock!)

Wastegate: Internal (don't want to be swapping anything out or fabbing external brackets)

 

I think 260hp to 290hp is a little high for the stock T3 to feel comfortable. I also don't want to run a ton of PSI if I can help it.


So far I am installing:

- 1982 L28ET with stock internals

- 1978 280z with '78 R200 diff and '78 5-speed transmission

- Megasquirt 2

- 240sx 60mm throttle body, 440cc Supra injectors, Walbro 255 fuel pump

- Greddy Intercooler 2.25" piping with HKS BOV

- 2.5" MSA downpipe to 3" mandrel bent exhaust with straight-through muffler

- Mishimoto radiator with dual 12" Spal electric fans
 

If I understand what I have been reading correctly, I want something with a lower A/R. Something around .57? I read on here that a user had a .48 that spooled at 1200RPM. That is probably a little extreme ūüėĄ. Not sure about trim. I would like it to be between $500-$800 if possible (no China turbos either).

So does anyone have any recommendation or experience with a T3/T4 turbo that spools at a similar RPM to stock?

 

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Edited by AlbatrossCafe

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T3/T4 hybrid with a .57 Trim is a good choice as well. Will easily meet your HP goals with room to spare. Will have a fairly quick spool as well. 

 

 Add a good adjustable FPR to your build sheet. An Aeromotive EFI Bypass regulator part #13129 is  a very good choice. 

 

You may want to consider jumping direct to 550cc injectors. Get Hi-Impedance injectors. Less hassle than dealing with the MS-2 Low-Z injector drivers, which sometimes can be a bit flaky.

 

IMHO, buy the 3.57 revision board. Uses Small Scale Integration and is Robotics assembled. Much less chance of human error with assembly ( soldering mistakes primarily ). 

 

PM me when you need a Tune and setup. I do Remote Tuning and initial setup. Can save you a lot of time and frustration. 

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At your goals I recommend finding a stock T3 and rebuilding/upgrading it to t4 compressor wheel. I may have the compressor housing for it actually. And I may have a spare turbo lying around internally gated. Also good choices are turbonetics for t3/t4 they are within your price range and you can get internally gated I believe with adding the gate on hot side.

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Anything under 3.5k spool really doesn't feel too much different to me. Cars with full spool/thresh hold super early on though tend to feel like they have a weak top end unless they are employing trickery via QSV or VVG. Honestly the only time you would notice is if you wanted to pass someone without changing gear, granted even in 6th, I can go from vacuum to boost in a second or so since cruising is at 2500rpm. My turbo spools pretty quick, I've data logged a friend's and his spools higher as his turbo is smaller, less efficient, and he has smaller displacement on a less efficient engine,  but really no complaints in speed or feel. The only two times I've noticed was when we were in top gear trying purposely to find the spool point and another when we were playing with a turbo miata, granted that may be more of a power to weight scenario.

 

If low end grunt is what you are looking for, bigger displacement or a supercharger might be more apt. 

 

I see you are local, happy to meet up and give you a lift sometime if you want to make a more informed decision.

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6 hours ago, Chickenman said:

T3/T4 hybrid with a .57 Trim is a good choice as well. Will easily meet your HP goals with room to spare. Will have a fairly quick spool as well. 

 

 Add a good adjustable FPR to your build sheet. An Aeromotive EFI Bypass regulator part #13129 is  a very good choice. 

 

You may want to consider jumping direct to 550cc injectors. Get Hi-Impedance injectors. Less hassle than dealing with the MS-2 Low-Z injector drivers, which sometimes can be a bit flaky.

 

IMHO, buy the 3.57 revision board. Uses Small Scale Integration and is Robotics assembled. Much less chance of human error with assembly ( soldering mistakes primarily ). 

 

PM me when you need a Tune and setup. I do Remote Tuning and initial setup. Can save you a lot of time and frustration. 

 

I'm actually getting my MS2 harness built by Softopz up there and he is preloading your tune ;) haha

 

I stressed over injectors for a while. But I think 440cc should put me right at 80% duty cycle if I go all the way to 300hp, according to this calculator: https://www.raceworks.com.au/calculators/injector-hp-calculator/ Since I already bought them, I'll give them a shot.

 

image.png.686eab6c4f518a328ece696f712d9b12.png

 

5 hours ago, seattlejester said:

Anything under 3.5k spool really doesn't feel too much different to me. Cars with full spool/thresh hold super early on though tend to feel like they have a weak top end unless they are employing trickery via QSV or VVG. Honestly the only time you would notice is if you wanted to pass someone without changing gear, granted even in 6th, I can go from vacuum to boost in a second or so since cruising is at 2500rpm. My turbo spools pretty quick, I've data logged a friend's and his spools higher as his turbo is smaller, less efficient, and he has smaller displacement on a less efficient engine,  but really no complaints in speed or feel. The only two times I've noticed was when we were in top gear trying purposely to find the spool point and another when we were playing with a turbo miata, granted that may be more of a power to weight scenario.

 

Actually you are right. I was looking through some videos of me accelerating and although boost can happen as low as 2400 RPM, I usually am operating between 3k-5k most of the time I am accelerating. So I might not need to go as low of a spool RPM as I thought. It is not necessarily low-end grunt that I'm after, but I just didn't want the engine to be a dog until it hit like 4000 RPM and then all of a sudden launches forward.

 

Which Turbo do you have?

Edited by AlbatrossCafe

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Something to keep in mind, is that turbos HAVE gotten better over the years, and something designed and built in the 70's like these old T3's is at a huge disadvantage compared to something modern. My point is that with a goal in the high 200's low 300's range, the only way you'll be upset with spool is to buy a cheap $200 ebay turbo which will likely be a chinese copy of a 40 year old design. Spend a little more and get something modern, and you won't regret it. I'd also advise you to get something water cooled if you can stomach the additional install requirements, as it dramatically improves bearing life. When you shut down your engine, you end up with stagnant oil in the center section and it just heat soaks since the turbo is running much hotter than the oils (even at idle after driving). Water cooled turbos take advantage of "thermal siphoning" where as long as the hot water has a free place to go, as it heat soaks at engine shut off, the hot water will want to escape pulling cooling water into the turbo. Obviously turbos without water cooling are also designed around that, but most of the newer designs you want for better aerodynamic properties will also require water cooling to be set up properly.

 

Also, while going to a small AR might spool the turbo sooner, and sound like a great idea, they can definitely be a bit top end limiting. Now, with the stock turbo head and camshaft, that's not much of a big deal since it's out of breath by 5500 anyway. But if you want to ever do any head work and/or swap the cam out and rev it up to 7k (and actually make good power up there( then you'll find a smaller AR turbine housing to be quite limiting.

 

To put another dimension on the table, people love to talk about how increasing load allows a turbo to spool up faster, so turbos tend to like long (small number) gearing. Personally, I find this to actually be a counter-productive way to think about it, and leads you to build a turbocharged car that drives more like a diesel, and focusing on the wrong part of the power band. A turbo is a GAS based device that is extremely dependent on pressure ratios. Yes, thermodynamics play a role, and loading an engine will create heat and create spool. Drive a turbo charged car on the freeway and go up and incline and you'll see this. Most responsive setups are very hard to stay OUT of boost going up a hill at the same throttle position as you were going a stead speed an flat ground. But, if instead of relying on load to see boost "sooner in the RPM band" and going with short (high number) gearing, you're likely to find you spool "sooner" based on time. You get the revs of the engine up sooner, it's swallowing more air over time, pushing more air over time into the turbo, creating spool sooner. If going with longer gearing was better for turbos, why not UPSHIFT to go faster? It doesn't make sense. And in that vein, if you're going with a laggier turbo, you can make up SOME of the difference by going up in gearing. I plan on running 3.9 in my 280Z, and I'm at 3.545 now. And going back to the earlier point, if you're making great power up to 7k you're more than offsetting the difference....

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That is very interesting to ponder.

 

You are correct, short gears will get up in RPM faster and spool later RPM wise, but will not be as noticeable since you will be in upper RPM most of the time. Taller gears will spool faster RPM wise, but will take longer to get in the higher RPM. If load was so good, then yes one should upshift to basically lug the engine making max load to spool the turbo, but then there is a differential in road speed to RPM that pushes the motor out of the power band. The practice of brake boosting would be a counterpoint, adding load without the penalty of being in the wrong gear for the speed is done quite frequently, the usefulness is limited to roll racing though. Same thing with stalling against a torque converter with an auto for drag racing. 

 

Interestingly, I stepped down from a 4.11 to a 3.7 final drive, and now I'm looking to go even lower with my new transmission. Maybe like 3.5 or 3.3. In my situation I can row through the gears almost too fast, making the gears taller via a lower numerical value final drive would lengthen my time in each gear as well as increase the overall speed. My turbo is on the lower portion of the efficiency graph so it would still benefit from load. It is a balancing act, lower it too much and you will shift the power band, raise it too much and the turbo won't be running at its most efficient island. Granted it is not something really discussed as swapping ratios and gearing isn't something most people contend with or is much of an option not in our community.

 

My turbo is a borg warner S257SX-E. Turbo tech is really changing, limiting yourself to certain restrictions may be detrimental as Gollum says.

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I ran a 3.90 in my 280Z, and first gear was essentially useless, so I went back to the 3.54.  I cannot attest to the "spooling", but I believe the reason I was able to get a faster ET with the 3.54 is I had one less shift to get to the end of the 1/4 mile.  My best was a 12.89 at 110mph, 5600' elevation.

Edited by SleeperZ

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Sleeperz, I also plan on running very short wheels. I don't expect 1st to be useful other than getting off the line smoothly around town. I also plan to run a lightweight clutch/flyhweel combo, and again, first will be for tame street driving. With my planned setup, I don't think it'd be beyond reasonable to launch from 2nd at the drag strip, but that's not the venue I'm building the car for...

 

As it is, with LESS power on the stock turbo with 3.54 gears, first was still went by extremely fast and useless in most scenarios. 

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1 hour ago, seattlejester said:

That is very interesting to ponder.

 

You are correct, short gears will get up in RPM faster and spool later RPM wise, but will not be as noticeable since you will be in upper RPM most of the time. Taller gears will spool faster RPM wise, but will take longer to get in the higher RPM. If load was so good, then yes one should upshift to basically lug the engine making max load to spool the turbo, but then there is a differential in road speed to RPM that pushes the motor out of the power band. The practice of brake boosting would be a counterpoint, adding load without the penalty of being in the wrong gear for the speed is done quite frequently, the usefulness is limited to roll racing though. Same thing with stalling against a torque converter with an auto for drag racing. 

 

Interestingly, I stepped down from a 4.11 to a 3.7 final drive, and now I'm looking to go even lower with my new transmission. Maybe like 3.5 or 3.3. In my situation I can row through the gears almost too fast, making the gears taller via a lower numerical value final drive would lengthen my time in each gear as well as increase the overall speed. My turbo is on the lower portion of the efficiency graph so it would still benefit from load. It is a balancing act, lower it too much and you will shift the power band, raise it too much and the turbo won't be running at its most efficient island. Granted it is not something really discussed as swapping ratios and gearing isn't something most people contend with or is much of an option not in our community.

 

My turbo is a borg warner S257SX-E. Turbo tech is really changing, limiting yourself to certain restrictions may be detrimental as Gollum says.

 The thing with Turbocharged engines is that they essentially react as a larger displacement NA engine.  You want to emphasize the Torque band rather than the high RPM band. We have a lot of experienced big turbo 510 guys out my way. Those who have been running Autocross, hill climbs and Road Racing have found that running a stock gear ratio such as a 3.9 on a 510 yields quicker Lap Times than running a shorter gear ratio such as 4.375's. Torque is what accelerates a car out of slow corners. The Turbo does seem to build more boost and Torque with more load on it.

 

I have 3.9 on my NA  1976 280Z with a ZX 5 speed. The 3.9's are perfect and really allows the engine to Rev quickly. BTW, engine is not stock and will pull hard to 7,000 rpm. But if I was building a Turbo motor, I would probably go with 3.5 gears. You want to utilise that fat and flat Torque band as much as you can.  

Edited by Chickenman

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So I have determined that starting to spool at 2400 RPM with full 7 PSI boost by ~2700 RPM (like the stock T3) is probably a little over zealous. I think that achieving full boost closer to 3000-3100 RPM is fine. I was just worried about reducing usable powerband since I have the stock cam and the engine falls off around 5500 RPM.

 

Sounds like a T3/T4 .57 trim .63 A/R turbo with a stage III wheel would accomplish this from researching many threads around this site.

 

Something like this: http://www.himni-racing.com/turbochargers/garrett-t-series-journal-bearing/garrett-t3-t04e-stage-iii-turbo-57-trim-475-hp

 

@Chickenman you mentioned .57 trim in an earlier post... do you have personal experience with using a similar turbo? Are my full boost @ 3000-3100 RPM goals within reason?

Edited by AlbatrossCafe

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Reading through this thread is there a reason why the T3/T4E 57 trim is recommended over the 50 trim? I haven't looked at the compressor maps for a while but I was under the impression that the 50 trim compressor is more ideal for the L28? 

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15 minutes ago, Dat73z said:

Reading through this thread is there a reason why the T3/T4E 57 trim is recommended over the 50 trim? I haven't looked at the compressor maps for a while but I was under the impression that the 50 trim compressor is more ideal for the L28? 

 

No specific reason in this thread. Only thing I can think of is that maybe 50 trim loses a little too much top end power. Do you have experience with either?

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I think room to grow would be the reason. From my recollection a 57 trim t3/t4 hybrid will get up to 400whp with a big displacement engine, so shouldn't be inefficient at the desired 260-290hp range desired. 

 

That turbo was exactly what I was looking at before I went with mine, same vendor too. The T3/T4 hybrid is still old tech, newer turbos have billet wheels, full face journal bearings if not ball bearing cartridges, better ratios, BW has extended tips as well, the only requirement that we can't meet here is the internal waste gate unless you start going way up in price, but for a bit more you could swing a pretty gnarly turbo.

 

In the same range there is this offering if money was a concern.

https://agpturbo.com/agp-turbo-cw-5257b/

 

You could also look at the older non sx-e series without the billet wheels for a savings 

https://agpturbo.com/borg-warner-agp-s251sx-turbocharger/

 

Or the SX-E series which is pretty nuts as far as journal bearing turbos go

https://agpturbo.com/borg-warner-s252-sx-e-52-61-12709095019/

Flows almost 10 more CFM with 1mm more than the standard series with the billet wheel

 

Or you can go full bannanas with an EFR

https://agpturbo.com/borg-warner-efr-6258/

Saves you from having to get a blow off valve and it has the integrated waste gate as well as water cooling and has insane specs

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4 minutes ago, seattlejester said:

I think room to grow would be the reason. From my recollection a 57 trim t3/t4 hybrid will get up to 400whp with a big displacement engine, so shouldn't be inefficient at the desired 260-290hp range desired. 

 

That turbo was exactly what I was looking at before I went BW. The T3/T4 hybrid is still old tech, newer turbos have billet wheels, BW has extended tips, the only requirement that we can't meet here is the internal waste gate unless you start going way up in price, but for a bit more you could swing a pretty gnarly turbo.

 

I'll have to check your external waste gate if I get the chance. I don't have a lot of capability to make anything custom so I was just trying to be as bolt on as possible. But I certainly would appreciate the newest tech that I can find. I'll start looking at some non T3/T4 options.

 

I can't see ever wanting 400hp on this car. I don't really have any desire to go above 300hp, so as long as driveability is good that is probably enough for me and maybe I don't need anything super fancy.

Edited by AlbatrossCafe

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I forget who, but someone on here has a really really good flowing waste gate adapter. It does add to the price overall, adapter plus wastegate, but you can get really good boost control.

 

I was in the same spot as you, wanting the best bang for buck, but being limited by finances, I couldn't swing for it until I had an unexpected amount of overtime to help fund it.

 

You say that now, and it may be the case, but with turbos stepping up isn't hard at all if your other systems (fuel and cooling) are up to the task. I remember when I built my entire car thinking anything over 200hp was silly. Super glad I at least had the tank with 8AN outlets and a cooling setup rated for 4-500hp. 

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Thanks guys, that makes sense. I don't have experience with either the 50 or 57 trim t3/t4e, just what I've read and looking at the compressor maps. In terms of real world performance how does the spool on the 50 versus 57 compressor on a 63AR turbine compare? 

 

If you're looking to retain the internal wastegate this may be viable: https://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Product_Code=ATP-WGT-023&Store_Code=tp 

 

 

Edited by Dat73z

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