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Point me in the right direction........


Guest bastaad525

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Guest bastaad525

Okay so I'm getting closer to getting my L28 Turbo into my '72...... gaaaaaaaah can't wait the tension is killing me.... can't stop thinking about it :shock: Well anyways, the engine is going in pretty much stock except for a few parts I want to put in right off the bat to get some good power outta her and hopefully make it a 13 second car. I was hoping some of you guys here could point me to where I might find good deals on some of this stuff, and maybe tell me what I'm looking at, price wise, for each part? The parts going in initially are:

 

Manual boost controller

Boost gauge (nothing fancy, cheapest I can find that works well)

Blowoff valve (1G DSM? seems to be the best deal, yes?)

 

Now as I understand it these are all the parts I need initially to be able to run 10psi, right? After these are in, I'll start saving up for some more goodies, looking for the best deals and general price ranges for these parts too:

 

Intercooler

Fuel Pressure Regulator (does it need to be RRFPR? or will just regular FPR work fine?)

Larger injectors (what size injectors? say if I'm shooting for around 250-300hp at the wheels as my ultimate goal?)

 

Also I have a question about the stock T3 turbo, how much boost can you get it to push? I've heard that they are only good for max 250hp at the wheels, about how many psi does it take to get that number? What happens if you boost any higher than that? I have a friend who says he runs 15psi on the stock T3 all day, with the above listed mods, and can run 20psi on race fuel, but somehow 20psi seems to be a bit much to get only 250 at the wheels.... is he full of it or what? I really want to hit the limit of what I can do with the T3, as the one I'm getting is like new, and it will probably be a long while before I can afford to upgrade to a bigger one, and anyways, given the spool characteristics of this turbo (as far as, they dont seem to really have any lag), and the fact that I really dont want an insanely fast car, just something that can eat a corvette or two.... I dont think I'll ever need to upgrade the turbo. Anyways thanks in advance for any tips you guys can give me, helping me build one hell of a fast car and saving a few bucks while doing it :-D

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Initially, you won't need a BOV. When you add an IC is when you may want to add a bypass valve if you are still running the stock ECU. The DSM unit works well.

 

You can get 250 to the wheels with the stock ECU and injectors. If you are shooting for 300, consider an aftermarket (standalone) ECU. The stock injectors and pump will not be adequate at that point.

 

You cannot push the stock turbo past it's capability - it just becomes a hairdryer at that point. If he's getting only 250 hp at 20 psi, he needs a better turbo - I get that with a hybrid T3/TO4 running at 14 psi (12 psi at sea level) and an intercooler. That's my next point. Get a good one. Don't skimp. At the very least, an NPR will work, but if you are serious, get a Spearco or a Bell.

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Bastaad - got your email, just been in the garage fighting this clutch issue. I will write you back soon with any info i can give. You'll get 13's, don't sweat it. I got that 13.3 and dont (didn't) have a lot of $ or add on parts to my '73. No manual boost controller, just wacked and threaded the wastegate actuator rod, removed the POV and plugged it with a 1" pipe plug, Boost gauge (autometer) - this is important - need to know exactly what boost you'r running...especially with a stock bottom end, top end and head gasket as i am, 1G DSM BOV - works great plumbed back in right after the AFM - $20, 9" "Green" air intake out in front of the radiator - not sure if this helped one ioda but, i know it didn't hurt. Electric fan, again, not sure if it really helped much but i know it didn't hurt. I was running about 9psi on 93 pump gas with no knock, with 3.54 and the BW-T5 and pulled the 13.3 - consistant 13.4-13.5's. I think you said you have a 3.90 and a 3.54 and i'm not sure which would make you faster down the 1/4. i would think the 3.90 but i don't have experience with it so i cant suggest. I do know i like the 5th gear with the 3.54 for cruising and that's mainly what my Z is for. I think 3.90's would be a little high in the R's for me down the highway. I'm running stock injectors, stock ZXT fuel pump and stock ECU. Like i said, you should have no problem getting into the 13's without blowing a ton a money. And before i get flamed, i'm not saying all the mods i did are the correct way of doing things but, it works for me until get the more inportant things done. Bastaad, i think i was running on the edge of REAL lean with the stock pump at the level i was at and would suggest one idea is to upgrade that when you get the $. I'll let you know how the Walbro 255lph does by itself without an aftermaket FPR in the leaness deptartment. I'll write more when i get a litttle time. Need to battle the clucth some more! ha. Later.

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Yes, Doug is right. The Dawes Boost controller is a better idea than cutting and adjusting the WG actuator arm. I have to get to grainger one of these days to build me one of these. 1 - I like making stuff and 2, i'm cheap :) BTW - I left out that i'm running a 2 1/2" mandral exhaust. You should definetly have this or 3" to let it breath. Cant wait until you get it and feel the power. Boost if fun and VERY addicting!

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Guest bastaad525

Kewl thanks for the replies thusfar guys..... Jersey I posted on your thread re: the clutch issue, I have the same clutch, and same symptoms, I'm thinking there is no way around it, just gonna have to adjust your pedal pretty much all the way out, and I also had to pull out the rubber stopper that adjusts how much free play in the pedal.... one other guy I know that ran the ACT had to do pretty much the same stuff.

 

So now I have a good idea of some bargain prices.... I had seen that do it yourself boost controller before but couldn't remember where to look for it.... that's a great price for one already made. I've already got my feelers out for a good price on an intercooler but it's gonna be outta my budget for a while, however I will probably spring the extra $150 to get the FPR right off the bat, the stock pump can put out a lot of pressure I think, and bumping up the pressure with the FPR should be enough to combat that lean top end, at least that's how I solved the problem when I built my high compression motor with the stock efi. I had LOTS of ping above 5k revs when I first built the motor, running super lean, FPR took care of it easy with only 2psi increase in fuel pressure. I finally got a chance to hear the turbo run without a muffler today, and was shocked at just how quiet it was, so for exhaust i'm just gonna run a 2.5" pipe as straight out the back as I possibly can, not mandrel bent but I'm thinking I wont need it if I can run it straight out, any crimping will be minor. Funny thing was this one had no pipe at all, just the downpipe off the turbo, ending right there by the tranny, and it was still quieter than my car. The POV is already off the intake manifold and plugged. I still have my K&N from when I had my last ZX, though I'm thinking it may not work, I didn't get to compare, the the diameter of the opening on the turbo AFM certainly seemed bigger than the opening from the N/A ZX one (can someone confirm this one either way?), which is what size K&N I have. Meaning I'd need a pipe with different diameters on each end or something like that, probably just easier to buy another filter. I'm in CA so I've only got 91 octane to work with, does this mean no 10psi for me? Has anyone ever adjusted the spring tension on the flap in the AFM to help richen up the mixture for more boost? About the BOV, wouldn't I benefit from it at all even if I don't have an IC? I thought it would help to keep the turbo spooled between shifts, and also extend the life of the bearing in the turbo? questions and more questions!

 

About my friend who says he's pushing 20psi on the stock T3, he never specified how much hp this was getting him, I was just inquiring how much boost you could get from this turbo, Yo2001 said that the T3 was good for up to about 250hp at the wheels, after that it was past it's efficiency, I was just wonderign at what level of boost this is achieved?

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Guest bastaad525

one more quick question, do you HAVE to run the 280z fuel tank to do this conversion? I ask because I just dumped some $100+ into comepletely cleaning and recoating my stock 240z tank, and dont want to spend who knows how much more to get another used tank in who knows what kind of condition. The guy doing the engine swap says he's done them with 240z tanks before with no probs, anyone here do this?

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You can use the 240 tank but if you run under 1/4 tank and take a turn, she'll cut out on ya...which is tough to handle if you're taking a turn with some good speed. There is a way that some put the pickup out of the bottom of the tank, probably from the drain hole but i'm not sure of the process. There's a bunch of articles in the archives because i found them right about at the stage you were at :) You'll have to run a bigger feed line from back to front to supply the FI. I ran a 3/8" SS that i got from Summit (cheap) and used the stock feed on my '73 (5/16") as the return. I did change the tank out with one from a '75 - it has the baffles and still fits in the older Z because of the spare tire configuration. Turbo AFM = 3". Turbo does quiet the car down a bit. I would think if you get the fuel there, you should be able to pull 9-10psi with 91. I haven't adjusted the spring on the AFM yet but many have and there is information in the archives as well. Yes, do the BOV. It helps a lot and it's cheap, the way i went anyway. And you're correct...it puts you right back on top of the turbo when you hit the next gear. I felt a big difference when i added mine. Thats my opinion and experience anyway. I just got my Z back on the road last night (actually 3am this morning) and have the boost cranked up to 12-13psi and i think i'm at or a little over it's peak efficiency. Thanks for the replies on the other thread. I did some part swapping and will post over there if you're interested. Later.

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I've already got my feelers out for a good price on an intercooler but it's gonna be outta my budget for a while' date=' however I will probably spring the extra $150 to get the FPR right off the bat, the stock pump can put out a lot of pressure [b']I think[/b], and bumping up the pressure with the FPR should be enough to combat that lean top end, at least that's how I solved the problem when I built my high compression motor with the stock efi. I had LOTS of ping above 5k revs when I first built the motor, running super lean, FPR took care of it easy with only 2psi increase in fuel pressure.

 

I finally got a chance to hear the turbo run without a muffler today, and was shocked at just how quiet it was, so for exhaust i'm just gonna run a 2.5" pipe as straight out the back as I possibly can, not mandrel bent but I'm thinking I wont need it if I can run it straight out, any crimping will be minor. Funny thing was this one had no pipe at all, just the downpipe off the turbo, ending right there by the tranny, and it was still quieter than my car.

 

The POV is already off the intake manifold and plugged. I still have my K&N from when I had my last ZX, though I'm thinking it may not work, I didn't get to compare, the the diameter of the opening on the turbo AFM certainly seemed bigger than the opening from the N/A ZX one (can someone confirm this one either way?), which is what size K&N I have. Meaning I'd need a pipe with different diameters on each end or something like that, probably just easier to buy another filter. I'm in CA so I've only got 91 octane to work with, does this mean no 10psi for me? Has anyone ever adjusted the spring tension on the flap in the AFM to help richen up the mixture for more boost? About the BOV, wouldn't I benefit from it at all even if I don't have an IC? I thought it would help to keep the turbo spooled between shifts, and also extend the life of the bearing in the turbo? questions and more questions!

 

About my friend who says he's pushing 20psi on the stock T3, he never specified how much hp this was getting him, I was just inquiring how much boost you could get from this turbo, Yo2001 said that the T3 was good for up to about 250hp at the wheels, after that it was past it's efficiency, I was just wonderign at what level of boost this is achieved?

 

That's a lot of questions... :shock: That's a good thing though. ;)

 

Ok, the stock fuel pump will NOT tolerate much pressure increase. I suggest you get a better pump before you go to an FPR. You can get very good, cheap pumps. I have a few used Bosch pumps with fittings to adapt to stock lines, $30 each, if you want.

 

2-1/2" piping is OK if it's mandrel bent. If you crush-bend the crap, it will be very restrictive, especially if you have the two 90* bends necessary to run it out the back in the stock location. You could get away with 3" crush bent, but I'd not recommend 2-1/2" crushed.

 

The diameter of the turbo AFM is 3", the same as a Z31 MAF. The n/a AFMs are smaller.

 

The BOV will not "keep the turbo spooled" between shifts. What it does for you is prevent compressor surge, which can destroy your turbo. You lose your boost if you throttle lift on a shift whether you have a BOV or not, and you have to build it up again regardless. Difference in re-spool time will be measured in milliseconds, not enough to notice. I've seen ZERO data to prove it improves ETs or otherwise.

 

At sea level some people have effectively boosted the stock turbo to 18 psi. Looking at the T3 super 60 trim map, this is WAY out of it's efficeincy range already. There is no benefit to trying to get more boost, because you wont get any more power. It's blowing hot air, so the boost pressure increase does not outweigh the density loss, and you increase the possibility of detonation. Not to mention you are exceeding the speed rating of the turbo and it will not last. That's why I say you can get 250hp out of the stock turbo and NO MORE, regardless of how hard you push it.

 

This diatribe is mostly opinion, so if I'm wrong, don't hesitate to correct me. HTH.

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Sleeper - I know with my BOV, i shift and the boost gauge reads right back about where i left off from the last gear. It wasn't like that before the BOV. It keeps the T3 spinning at a good rate between shifts instead of back pressure/slowing the turbo down/compressor surge. I don't know...I wasn't looking for any big gain with this because i didn't spend much for it ($20) but i did find out it made a good difference for me and worth ever penny. My opinion.

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Guest bastaad525

I too, didn't think a BOV would actually gain me anything, as far as a faster time or anything like that. Initially I wanted one for the sake of keeping the turbo in good shape for as long as possible, but just heard that one side effect was keeping it spooled better between shifts. Either way, as long as it does serve some purpose, gives some benefit, and is a cheap mod to do, then it's for me :) Hmmm so I was right about the turbo afm, just from looking at it I could tell it was bigger, which means I'm assed out on using my old K&N from my N/A ZX. Or not... I'll have to see what I can do with it, $50 is $50. again, about the piping, since I'm not going to run a muffler, I dont see why I'll need to do those two 90 degree bends at the rear of the car, maybe two much softer bends or even just one little bend starting from where the exhausts passes the rear suspension, just to get the tip of the exhaust poking out about where it would stock. But since they wont be much of bends I figure I can do crush bent 2 1/2", as they wont be crushing it down that much. Or if I can run 3" off the stock downpipe I will. Also, if there's any way I can get away with just not bending it at all, I will.

 

About the fuel pump, how much pressure are they good up til with an FPR? I adjusted mine up to 46psi, enough to make it run rich and very badly on my high CR motor, then back down to like 42 where it was running perfect, so I figure they're good up til at least 46, which should support some amount of boost over 10psi, if stock pump w/o FPR can do that. But, for whatever I'm gonna end up doing in the future, I have now added an upgraded pump to my list of must-get parts.

 

Jersey did you get your BOV at a junk yard? if not where'd you get it so cheap? 1G DSM right?

 

Sleeper, so I would need about 18psi to get that 250rwhp with the stock turbo? This is what I'm trying to figure out, if 250 is the max it can do (dont get me wrong I'm not arguing that point!) and now you're saying that 18psi is the most you can boost it efficiently (which i dont doubt either, actually I thought it would peak at efficiency even lower than that), then 2+2= I would need to be at that max efficiency of 18psi, to be making that max power of 250hp at the wheels? One thing I dont understand.... I thought I heard/read somewhere that 1psi increase in boost gets you around 6% increase in power. Okay so... (heheh try not to fall asleep here)

 

A stock 280ZXT was said to have 180hp net (flywheel)

Take away about 15% from that for hp at the wheels (typical driveline loss when dyno testing) gives you 153 hp, this is at stock boost of 7psi

Increasing the boost to 10psi, commonly gives rwhp #'s in the 200-220 range, depending on other mods, hence 3psi increase = roughly 60hp increase, or 20hp per psi, or roughly 7%, really close to that 6% estimate (obviously this is incorrect seeing as i wasn't increasing that one psi at a time, and therefore it wasn't exactly 20hp per psi, as each psi increasing a set % amount, would result in MORE hp gain with each additional psi increase). So lets just say 6% to keep in consistent. Now, start with the average hp at 10psi, lets say 210 at the wheels (very close to what Jersey's 1/4 times and trap speed indicate):

 

210 + 6% = 227 at 11psi

227 + 6% = 236 at 12psi

236 + 6% = 250 at 13psi

 

LOL dont ask me why I'm getting so detailed about this.... normally I hate math!! Must be the sleep depravation from me staying up all night thinking about how fast my Z's gonna be! So WILL a stock turbo put out 250 hp at 13psi? or does it go up much slower than that after around 10psi? OR if as you say 18 is the max efficient psi, but 250 comes on at around 13, shouldn't you be able to get much higher than 250? If you can max out the power at 13psi why would anyone boost any higher than that.... I dunno it's all pretty confusing, my main thing is that I will be tryign to get as much as I can out of the stock turbo, and I'm just trying to figure out what it's gonna take for me to get there. Whatever it is, that's the limit I've set, as I promised my g/f no super expensive mods like buying another turbo! Anyways, thanks again for the info guys :)

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How much is your muffler shop going to charge you for a crush bend system? My current exhaust (3") cost me two 90 deg mandel bends and about 10 feet of piping. Magnaflow makes aluminized mandel bends for not a lot of money - imported to Canada they were about 25 USD each. You just cut and mig them together. OK - I built my own downpipe which used 2 90 deg and about a foot of ss pipe. But seriously - if you are looking to push the stock turbo to big boost levels - use minimum of 2.5 mandel or go 3". I ran my stock T3 to about 17-18 PSI (15 PSI at the intake - not sure how many PSI I was loosing through a bad intercooler) and got down the quarter in 12.9. Big fuel pump, SDS and stock injectors - and just a 3" downpipe with a turndown in the tunnel. Pretty loud at WOT. I sumped my stock fuel tank and ran 3/8 line. The sump is pretty simple - a 1.5" long piece of 4" pipe, bottom closed up with sheet steel. Drill a hole in the back, weld a fitting in. Clean out the tank, drill 4 large holes (3/4") in a pattern on the lowest part and weld the sump on the bottom of the tank. I cleaned my tank with Castrol Superclean and welded it up with the MIG. Good luck - keep us posted.

Oh yah - BTW - stock T3 max efficiency is from about 3K to 4K RPM on the 2.8L engine. Becomes very inefficient above 5K - I shifted my car at 5K and rode the Torque curve :twisted:

Cheers - Doug

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About the fuel pump' date=' how much pressure are they good up til with an FPR? I adjusted mine up to 46psi, enough to make it run rich and very badly on my high CR motor, then back down to like 42 where it was running perfect, so I figure they're good up til at least 46, which should support some amount of boost over 10psi, if stock pump w/o FPR can do that. But, for whatever I'm gonna end up doing in the future, I have now added an upgraded pump to my list of must-get parts.

 

Sleeper, so I would need about 18psi to get that 250rwhp with the stock turbo? This is what I'm trying to figure out, if 250 is the max it can do (dont get me wrong I'm not arguing that point!) and now you're saying that 18psi is the most you can boost it efficiently (which i dont doubt either, actually I thought it would peak at efficiency even lower than that), then 2+2= I would need to be at that max efficiency of 18psi, to be making that max power of 250hp at the wheels? One thing I dont understand.... I thought I heard/read somewhere that 1psi increase in boost gets you around 6% increase in power. Okay so... (heheh try not to fall asleep here)[/quote']

 

Well, the stock pump flows about 95 liters/hr at 50 psi, at a rich mixture, that is barely enough for 250hp. If you increase the base pressure to over 40, then run boost on top of that, you will choke that little thing down in a hurry.

 

Also, steer clear from rules of thumb regarding hp increases with boost. Boost pressure is a by-product of airflow restriction, and has nothing to do with the amount of air the engine is flowing. Compare the power level running 10 psi without an intercooler and 10psi with an IC - same boost pressure at the manifold, but a massive difference in power. The same thing happens when you upgrade to an efficient turbo - same boost pressure, tons more power. The key is air temperature. Cold air is more dense, the cooler the air, the more power you will make. Just look at the compressor maps and you will see how crappy the T3 really is. With the stock setup, it is past it's peak efficiency with any boost increase over stock. At 250hp, you are off the chart, meaning less than 60% efficiency.

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Guest bastaad525

yikes... thank you for the info Sleeper. Yeah I figured temps start coming into play and the % of gain would go down pretty rapidly after a certain point, I guess that point being stock boost. Makes sense. About the fuel pump, I wasn't sure about that but now I'll probably do it right off the bat when I do the engine swap, since I found they are not expensive at all. This thread has really brought me some good info :) but also lots more questions.... like.... is it really better to shift as early as 5k if you're running the stock turbo? I'm used to turbo guys talking about running it all the way to redline to get the most boost time out of it and land right back on boost when the shift. The other thing I'll have to put off for a while is taking the new setup to the dyno to see how the power and torque curves are and do any fine tuning.... the best dyno I knew of (read: cheapest) closed down, and I haven't found another good place yet.

 

Another question comes to mind, if you have a N/A engine and a turbo engine, lets say both have identical peak power and torque numbers (thought probably at different rpms) how would the curves differ between the two? In otherwise identical cars, would either one be faster and why?

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Bastaad - you aren't too anxious about getting this car, are you? haha! Believe me, I am as bad or probably worse than you when something is just at my fingertips. Like the 12 second 1/4 which I WILL get tonight! hopefully :) Hey sleeper..watch the "crappy" T3 talk!!! (i really need to upgrade to a t04 make some REAL 1/4 mile #'s :) ) And this is my take on the time to shift with the turbo thing. I don't have loads of experience yet but, this is what i've found. Without the I.C. runing about 9psi boost, the Z would pull strong all the way to just about 6k rpm and then i could feel a bit of drop off. That's about where i shifted before. Now with the I.C. and running about 12-13psi (still stock T3) she seems to start losing power around 5.5k rpm. I will see tonight at the track what works best with this setup - running more boost. I'm thinking that pushing more boost through the T3, ever though it's cooler air cause of the I.C., it's efficiencly level is not as good causing the power range to lesson, even though it seems stronger when it is in the power range at this level of boost. Hard to explain and hope i didn't confuse you. I haven't dyno'd this even and have no hard evidence on what i'm saying is even remotely correct but this is just what i feel in my Z. When i ran the N/A L28 10:1 in this same Z, i'd pull it all the way to about 6500 and she would pull all the way through. I'm not technical enough with the #'s to answer your "which would be faster" question but, i'll give it a shot - I would think the turbo engine would be faster, the N/A would be quicker because of the better bottom end tourqe (higher compression)

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The TQ curve for a stock turbo engine is pretty flat from about 3.5K to 5K. So- the quickest time down the track for me was shifting at 5K and letting it fall back into the TQ hump. With the dawesdevice or granger boost controller - they don't open the WG until the target boost is reached - it spikes a little bit - not more than 2 psi. But the area under the boost curve - (TQ) is much larger than stock. I think I made about 40 runs with the stock turbo at 17 psi. It didn't blow up but it wasn't going to be there for the long run.

Good luck - Doug

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Guest bastaad525

Heheh me anxious? Can you tell?? :shock:

 

yeah it's drivin me nuts... so close now but still so far away... for six years I've wanted to do a turbo motor in a 240, so I should be able to handle another two month wait right? HAH! Now when ever I'm not keeping myself occupied at work or out with the g/f, it's all I think about.... even keeping me up at night sometimes just figuring things I'm gonna do and how fast I'm gonna be and all the rice I'm gonna ROAST. Anyways thx again for all the info guys, building me up a solid information base on how turbos work, little by little, which is good becuase until now I really didn't know anything about them other than that they made you fast :twisted:

 

okay but more questions, about that boost spike with the manual boost controller, wouldnt that be something to worry about? that's when the boost shoots up and peaks higher than your desired boost limit right?

 

Also, what the heck is boost creep?

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