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L28ET Street Car.. What size Turbo.....


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OK.. so i am still in the planning stages.. but have a good idea of what i am looking to do and get out of my car... The car will be a 72 240z, w/ an L28ET, P90 head. I am planning on breaking down the motor and just giving it a refresh.. not really building it up.. just refreshing worn old 150K + old parts.. The head i will send out to get cleaned up.. new valves and seals.. and give it a fresh monting surface.. no porting.. I was going to go w/ a MSD igintian and some sort of EFI software.. I was leaning towards a T3/T4 hybrid turbo, w/ a downpipe and 3" exhaust. higher output fuel pump.. larger injectors.. and a new fuel rail.. better plugs, waste gate, BOV, Intercooler, 60mm throttle body

 

OK.. so here is what i want from the car.. This is NOT a daily driver.. though i will occasionally take it to work when its nice out.. This will be my weekend cruiser / toy car w/ the occcasional auto X.. not really a track or drag car at all.. just street fun.. Looking for something around 300rwhp.. was hoping to run 15psi or less.. depends on what i need to reach numbers... and would like power to be there close to 3K rpms.. don't want an NA car w/ 150hp.. then at 5K the boost hits and power doubles.. would like full boost to hit early.. and stay through 6.5k...

 

 

hope this is realistic.. so.. will the t3/t4 be sufficient.. and is what i am planning good for my expectations....

 

any suggestions / changes i need to consider to get what i want.

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if you want full boost at 3000 then use a stock T3 turbine.

 

A good compressor to use for the L28 is a T04E-50 trim. You will need a 1/2 inch turbine spacer to add exhaust manifold clearance for the compressor.

 

A stock turbo cam will not make power to 6500 rpms. They pretty much quit making power between 5,000 and 5,500 rpm. A non-turbo cam will extend the power out another 500 rpm. And the MSA stage 1 turbo cam will make power to 6,000 or 6500 but may have a little too much overlap for a stock turbine, but the down pipe may get you enough flow to run that cam.

 

what sort of efi software are you talking about?

 

what efi system do you have now?

 

A stock rebuilt is a good idea. should cost about 1000.00 with new pistons.

 

You most likely will not need new valves. Just get a valve job.

 

stock turbo spark plugs are good enough

 

no need for msd ignition, but you do need an efi system with ignition timing control and a coil pack (6 positions)

 

A msd 2225 fuel pump is a good pump for your application. cheap. durable, and flows enough for 500hp.

 

get a aeromotive fuel pressure regulator with a 1:1 reference.

 

You could use the stock wastegate with a boost controller. much simpler install.

 

You will also need a 240mm flywheel, clutch, and pressure plate to hold the torque.

 

could make around 280hp with the stock turbo cam and 15 psi, 290 with the na cam, and 300 with the msa stage 1 turbo cam.

 

you will need an IC to run over 10 psi of boost.

 

A street car needs torque at low rpms and lots of it. A stock exhaust turbine, small cam, and 15 psi of boost makes a fun street car. You have the right idea.

 

Don't use a stage 3 exhaust turbine, it make the car feel lazy at low rpms and will not make full boost until 3500 rpms. Not good for the street (if you want low rpm torque)

 

use low impedance injectors between 370 and 450cc. It's very important to use low impedance injectors for a turbo application. And make sure the efi system is able to run low impedance.

 

good luck

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My Z is basically this setup. But I am wanting around 380-400wheel. From what I have been researching.. A t3/to4E 57 or 60 trim compressor wheel and a .63 exhaust housing. The only questions I have are.. Is the stage 5 / P trim turbine wheel better then the stock or stage 3 turbine wheel?And will this wheel go into a .63 housing? Just like you I would really like nice boost and power down low.. I think garrett76ZT on here used to have a similar turbo and made 420rwhp at 20psi of boost and had full boost by 3300-3500. I cannot remember his exact specs though. I took the stock turbo to about its max and then had a baby t3/t4 turbo all wrapped up in the T3 housings. The problem I have with the stock turbo is, you can hit 18-20psi of boost but it falls off to around 17 or so..

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if you want full boost at 3000 then use a stock T3 turbine.

 

A good compressor to use for the L28 is a T04E-50 trim. You will need a 1/2 inch turbine spacer to add exhaust manifold clearance for the compressor.

 

A stock turbo cam will not make power to 6500 rpms. They pretty much quit making power between 5,000 and 5,500 rpm. A non-turbo cam will extend the power out another 500 rpm. And the MSA stage 1 turbo cam will make power to 6,000 or 6500 but may have a little too much overlap for a stock turbine, but the down pipe may get you enough flow to run that cam.

 

what sort of efi software are you talking about?

 

what efi system do you have now?

 

A stock rebuilt is a good idea. should cost about 1000.00 with new pistons.

 

You most likely will not need new valves. Just get a valve job.

 

stock turbo spark plugs are good enough

 

no need for msd ignition, but you do need an efi system with ignition timing control and a coil pack (6 positions)

 

A msd 2225 fuel pump is a good pump for your application. cheap. durable, and flows enough for 500hp.

 

get a aeromotive fuel pressure regulator with a 1:1 reference.

 

You could use the stock wastegate with a boost controller. much simpler install.

 

You will also need a 240mm flywheel, clutch, and pressure plate to hold the torque.

 

could make around 280hp with the stock turbo cam and 15 psi, 290 with the na cam, and 300 with the msa stage 1 turbo cam.

 

you will need an IC to run over 10 psi of boost.

 

A street car needs torque at low rpms and lots of it. A stock exhaust turbine, small cam, and 15 psi of boost makes a fun street car. You have the right idea.

 

Don't use a stage 3 exhaust turbine, it make the car feel lazy at low rpms and will not make full boost until 3500 rpms. Not good for the street (if you want low rpm torque)

 

use low impedance injectors between 370 and 450cc. It's very important to use low impedance injectors for a turbo application. And make sure the efi system is able to run low impedance.

 

good luck

 

Thanks for all the info.. helps me make some choices..

 

with regards to the overlap w/ the NA cam and stock turbo.. would i be better off going w/ the t3/t4 and the na cam....

 

i was thinking of going possibly the megasquirt efi..

 

not sure if it pretains to the turbo L series engines.. but i have read alot of posts about these engines being designed to rev to 7000rpm.. is this doable.. or wantable on a turbo engine?

 

i have seen a few people using the Halset hy35 turbo... how would that rate w/ this application?

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Thanks for all the info.. helps me make some choices..

 

with regards to the overlap w/ the NA cam and stock turbo.. would i be better off going w/ the t3/t4 and the na cam....

 

i was thinking of going possibly the megasquirt efi..

 

not sure if it pretains to the turbo L series engines.. but i have read alot of posts about these engines being designed to rev to 7000rpm.. is this doable.. or wantable on a turbo engine?

 

i have seen a few people using the Halset hy35 turbo... how would that rate w/ this application?

 

Not just any t3/t4. You need a T04E with a 50 trim on a stock L28 T3 turbine. Makes a big difference.

 

Yes, megasquirt II would be a good idea. Get it with low impedance drivers and ignition timing control.

 

Yes, 7,000 rpm is very doable with a L28. However, you get around a 3000 rpm power band. So, if it makes power to 7K, then it will not make power until 4K. Power from 3K to 6K is better for the street, so set it up with that in mind.

 

Sorry, no experience with HY35 turbos. The compressor maps seem pretty good for a L28, but not as good as a T04e-50 trim (IMO). The good thing is hy35's are cheap and easily found on ebay. Not sure how the exhaust turbine works with a L28, but I'm sure it will be harder to install as compared to using the stock turbine and waste-gate with a prefabbed msa down pipe.

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Not just any t3/t4. You need a T04E with a 50 trim on a stock L28 T3 turbine. Makes a big difference.

 

Yes, megasquirt II would be a good idea. Get it with low impedance drivers and ignition timing control.

 

Yes, 7,000 rpm is very doable with a L28. However, you get around a 3000 rpm power band. So, if it makes power to 7K, then it will not make power until 4K. Power from 3K to 6K is better for the street, so set it up with that in mind.

 

Sorry, no experience with HY35 turbos. The compressor maps seem pretty good for a L28, but not as good as a T04e-50 trim (IMO). The good thing is hy35's are cheap and easily found on ebay. Not sure how the exhaust turbine works with a L28, but I'm sure it will be harder to install as compared to using the stock turbine and waste-gate with a prefabbed msa down pipe.

 

 

so you recomend that turbo w/ the stock wastegate.. not an external wastegate.... what is the difference between the trim and the a/r?

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Well, yes and no. Installing a stock wastegate and MSA down pipe on a T3 turbine will be very easy and good enough for 300hp.

 

Installing an external wastegate would be better but gets expensive and complicated. And installing a hy35 turbo will also lead to some custom fab work.

 

So to keep it simple and good enough for a high torque, low rpm street engine....then use a stock t3 turbine, stock wastegate, and msa down pipe. (2-1/2 down pipe is all you need).

 

Save your money for a megasquirt efi system. And if you lower your goal to say, 250hp at the tires then you could get by with a completely stock turbo and save a bunch of money. 250hp at the wheels in a 240 still makes a very quick car.

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Well, yes and no. Installing a stock wastegate and MSA down pipe on a T3 turbine will be very easy and good enough for 300hp.

 

Installing an external wastegate would be better but gets expensive and complicated. And installing a hy35 turbo will also lead to some custom fab work.

 

So to keep it simple and good enough for a high torque, low rpm street engine....then use a stock t3 turbine, stock wastegate, and msa down pipe. (2-1/2 down pipe is all you need).

 

Save your money for a megasquirt efi system. And if you lower your goal to say, 250hp at the tires then you could get by with a completely stock turbo and save a bunch of money. 250hp at the wheels in a 240 still makes a very quick car.

 

 

so.. if i do my refersher rebuild on the engine.... stock turbo and waste gate.. down pipe with exhaust.. intercooler.. megasquirt.. coil pack, fuel pump and injectors..

 

get around 250rwhp.. and if that gets boring.. then i can upgrade the turbo

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pyro.. why are you so set on low imp. injectors? thats a great thing about megasquirt. It can run either or.

The holsets are amazing turbo's. I have a Holset HE351cw i have a stock motor and cam and i hit boost threshold at 2400rpm if i lug it in 4th and have full boost at 3000-3100rpm so how is that not a good turbo considering its boost characteristics are very similar to the stock t3? It doesnt run out of steam on top either. i run it to 6k all the time. No it doesnt keep building power but its not falling off like the stock t3 does either.

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pyro.. why are you so set on low imp. injectors? thats a great thing about megasquirt. It can run either or.

The holsets are amazing turbo's. I have a Holset HE351cw i have a stock motor and cam and i hit boost threshold at 2400rpm if i lug it in 4th and have full boost at 3000-3100rpm so how is that not a good turbo considering its boost characteristics are very similar to the stock t3? It doesnt run out of steam on top either. i run it to 6k all the time. No it doesnt keep building power but its not falling off like the stock t3 does either.

 

A turbo engine requires a lot of fuel on boost. So bigger injectors must be used. And the problem with big injectors is their duty cycles needs to be very low at idle. And low impedance injectors have much better fuel control at low duty cycles, thus allowing a better idle. This is only an issue with boosted engine that require a wider range of fuel volume.

 

I said the hy35 turbo compressor maps looks pretty good, but not as good as a t04e-50 trim (which is not a stock turbo). I also said that I wasn't sure how the hy35 turbine works with a L28. And since the turbine effects the how soon the turbo spools up, it is an important characteristic to know. But I'm pretty sure the stock wastegate will not bolt to it. What did it take to bolt the hy35 to the stock exhaust manifold, wastegate, and downpipe?

 

The stock turbo engine falls off on power between 5000 and 5500 mainly because of it's small cam. Yes, the stock turbine restriction and the hot compressor doesn't help either. But I would guess that your power is falling off hard at 6000 rpm if you are using a stock cam. I had a stock turbo cam for a short time and it would rev to 6000 but not very well. Most dyno's I have seen peak at 5200 rpm when using a stock turbo cam regardless of turbo used.

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http://www.cardomain.com/ride/635763

635763_25_full.jpg

 

Heres a dyno sheet showing the stock turbos abilities. This was 230 hp and 300 ftlbs. You said you wanted 300hp but would 300 ftlbs do? (torque>hp)

 

The link above is the owners page. As stated if your looking for 300 ftlbs this might be an easier route.?.

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Yeah, make sure you know which one you are getting. I have one from an 03 or 04 IIRC. It's an HE351 or something of that nature. Basically an HY35. Generally you need to spin the center section and compressor housing and then find a way to mount a wastegate actuator on it. The ones with the Holsets are set to about 22 psi (or thereabouts). The thing is, Holsets are longer from end to end and a standard T3 wastegate actuator needs a bit of extending. Likewise, you have to find a way to mount the actuator to the compressor now that you've spun it around.

I bought a new HKS adjustable actuator (for an SR30 turbo) and lengthened it by welding the attachment piece that came with it onto the end of the attachment piece from the original Holset. This was the tip still spins on the threaded portion to adjust the tension on the wastegate. It cost about $100 on ebay. For the mounting of the wastegate actuator, I cut the original mounting flange off of the compressor housing and welded it in the new location; approximately 180 degrees around from the original placement.

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