Had to change this topics name (was the Jersey/BOV topic)

[Drax240z]

The turbo engines are supposed to be 200ft-lbs stock.

 

Even at 5.5psi boost and 4k revlimiter, my 240z is MUCH faster than my 260z with a NA/L28 setup, which ran low 15's on a g-tech.

[Guest bastaad525]

faster by how much Drax? I agree that the best way to find out will be when I get the car back, and I do know that the turbo is gonna put out more torque, but I dont see it putting out enough to make it so much faster at stock boost levels. Again the point is almost moot because I'm only going to leave it at stock boost for a very short while, enough to make sure everything is working right, then it's up to 10psi, where I have no doubt it will be faster than my N/A It would just be very interesting to find out how well it would perform at stock boost.... problem is no one seems to have even bothered finding out.... everyone just ups the boost as their first 'mod'. Ah well, don't get me wrong I'm not trying to argue really... I guess I have a certain measure of pride from the investment into my N/A engine, in that I was certain I had gotten it to power levels higher than a bone stock turbo motor. So it's just gonna make me kick myself even more if I put this turbo in bone stock and it does end up being faster than the motor I built, and realize even more how much money I essentially wasted Then again it would only benefit me more in the end, as I may just end up opting for longevity and sticking with stock boost levels, if it would still mean a faster car, that'd be enough for me.

[SleeperZ]

Trust us, the turbo will be faster.

[Jersey]

And you wont be at the "stock" boost level for as long as you think, trust me, I know first hand. It's VERY addicting

[Drax240z]

Well lets assume that the ~1.5PSI I've lost due to intercooler and piping is worth 22hp. (1psi boost ~= 15hp) 22hp should be a very noticeable gain in seat of the pants, as its somewhere around 15% gain. With that considered, comparing it to my 260z/L28/3.9:1/4 speed car is silly. This engine in a 240z with stock boost levels might not pull away from it in first gear, but after that it would be all over but the crying.

 

You are right though, since the point is basically moot, and none of us will run stock boost levels for long. I would suspect that the stock turbo engine will be faster than your hopped up NA engine, though I don't know your list of mods.

 

I have a very poor feel for how much faster my car would be in the quarter, so I won't speculate a number. I'll just say "significantly" faster. However, remember I am going from driving a 260z with big bumpers to a 240z at the same time, so there is some weight reduction there as well.

[BayAreaZT]

I may just end up opting for longevity and sticking with stock boost levels, if it would still mean a faster car, that'd be enough for me.

 

Yeah right Once you feel 10psi you won't want to go back to stock, once you feel 12psi you won't want to go back to 10psi and so on and so on......

[SleeperZ]

I may just end up opting for longevity and sticking with stock boost levels' date=' if it would still mean a faster car, that'd be enough for me.[/quote']

 

Yeah right Once you feel 10psi you won't want to go back to stock, once you feel 12psi you won't want to go back to 10psi and so on and so on......

 

And keep in mind, higher boost levels are not necessarily costing you longevity. If you have correct fuel mixture and timing, and an intercooler, you will be making more power with added reliability - your intake and exhaust temperatures will be cooler than stock; that and keeping your RPMs under control will virtually guarantee a reliable fast ride.

[Guest bastaad525]

hmmmmm okay maybe this IS for the sake of argument.... no one is presenting me with any facts to the contrary.... to say that a bone stock turbo motor with stock boost would be faster in the same car, than my built up high compression L28.

 

The specs of my N/A motor are:

L28 block overbored .060

Flat top pistons

Approx. 10.3:1 compression

N42 head, minor porting

Stainless steel swirl polished valves

.480 lift 270 duration cam

Rebuilt Ztherapy SU's with SM fuel needles

Open K&N filter

MSA 3-2-1 header into 2.5" piping, running thru glasspack and straight thru muffler

MSD ignition running a 280ZX distributor

Motor dynoed 171hp@5500 at the wheels and 170 ft lbs of torque @ 5000rpm

 

As far as I know the at the wheel #'s of this motor exceed the stock turbo's #'s at the wheels. So with all things being equal if this motor is putting out more hp and torque than a turbo running stock boost, how would the turbo be faster? Before I was just wondering but now since everyone seems to feel the turbo would be faster, I really want to know just what would make it so? All other things being equal, how would a motor with lower hp and torque outrun the higher #'d motor?

 

mind you, I really dont understand exactly what a turbo does performance wise, I kinda get the basics, but obviously you guys know more than I, so please explain why you feel a stock boosted turbo would still outrun my built N/A? Yes the point is mostly moot but now it's just a matter of curiosity!

[Guest bastaad525]

HAS anyone ever dynoed a stock turbo motor at stock boost? Has anyone raced a 240 down the 1/4 with a bone stock turbo?? Anyone have any of those numbers?

[Drax240z]

Well this is the first time you've actually listed specs on your motor, so maybe we can be more educated about our comments now.

 

You can have lower power and torque peaks, and still be faster. How? Area under the curve. Your other engine might have made 170ft-lbs @5000rpm, but what about 3000? A turbo engine makes it torque maximum at 2800rpm and it won't drop much as the rpm's get higher.

 

Now you have a pretty extensive list of mods to your motor. Now that I see the mods, and see that you have dyno numbers with power at the wheels, I'm not certain a stock turbo engine will be faster. I suspect that at stock boost the 2 engines will be very close. But again, who runs stock boost anyway?

[Guest bastaad525]

On the dyno the N/A engine was at 160ft lbs by 3000rpm, rises only 10ft lbs by the 5000rpm peak, stays pretty flat then drops off quickly after about 5500, down to 125 ft lbs at 6500, which is where they stopped the pull. Up to 5500 the whole thing looks very flat. Sorry I should have given more details about the engine sooner I thought the HP and torque numbers would have been enough. I do figure the turbo will be close at stock boost, but I will be very surprised if it is actually faster than the N/A was.

 

The other variable in everything though is that the turbo engine will be mated to a totally different trans and diff (N/A had a '77 five speed and 3.9's, turbo will be an '82 five speed and 3.54's). I can't even pretend I know how this will effect everything....

[mobythevan]

Go here [/url]http://www.sweetspotproductions.com/psanders/images/1st-dyno-chart.jpghttp://

 

and check out this dyno chart. I forgot who's site this is, but it is a dyno of stock 7psi engine as far as I can tell. Look at how it makes nearly 200lbs torque at 2800rpm. And also how flat the torque curve is afterwards. Like others have said, area under the curve and gearing to match that torque are the most important things for the quarter mile.

 

Have fun..

 

 

[Guest bastaad525]

hell you weren't kidding!! nearly 200ft lbs and it comes on quick. Are you sure that's at stock boost though? The torque # and the HP peak seem a bit off for stock. Thanks for that link though moby. One thing I dont get with that dyno sheet though, why does the torque and power start dropping so early and why did they end the pull at 4600RPM? Is that typical for the ZXT or is there something wrong with his setup? I know nissans factory specs for the ZXT were 180bhp @ 5600 rpm.... anyone have any idea why they would have cut the run so short?

 

By the way does anyone have/remember the stock 0-60 and 1/4 times for the 280zxt's?

[Guest bastaad525]

Just called the mechanic for an update the turbo engine and '82 five speed are in today the diff goes in and then all thats left is the wiring, which I assume he will start today as the diff shouldn't take too long. So we're still on track for having the car done by this weekend the wait is killing me! I guess the wiring is the big variable hopefully nothing goes wrong there, that's the only part I have any worries about. Still, he did get a lot done in only two days time so that should be a good sign....

[SleeperZ]

hell you weren't kidding!! nearly 200ft lbs and it comes on quick. Are you sure that's at stock boost though? The torque # and the HP peak seem a bit off for stock. Thanks for that link though moby. One thing I dont get with that dyno sheet though' date=' why does the torque and power start dropping so early and why did they end the pull at 4600RPM? Is that typical for the ZXT or is there something wrong with his setup? I know nissans factory specs for the ZXT were 180bhp @ 5600 rpm.... anyone have any idea why they would have cut the run so short?

 

By the way does anyone have/remember the stock 0-60 and 1/4 times for the 280zxt's?[/quote']

 

Check out my dyno sheet (stock motor) in my personal gallery. My power peaks at 4500 as my torque drops so sharply. I can't understand how the stock motor/stock turbo & boost supposedly peaks power at 5600...

 

And the stock dyno sheet looks about right. 153hp to the ground - I can see 30hp loss in the drivetrain, and the power hadn't peaked yet, they just aborted the run early. Torque curve is a lot flatter than mine...

[Guest bastaad525]

I'm used to seeing really peaky torque curves on turbo motors. I also thought it didn't look like the power had hit it's peak, if they had kept going past 4600 I think it would have gotten a higher number, which again makes me wonder if that is in fact running at stock boost. Stock, the turbo was rated at like 205ft lbs of torque at the fly, I dont see how it would only lose 10 ft lbs down at the wheels. And if the power had kept going up past that point, lets just say it did peak out at 5600 like Nissan claims, it would have definately peaked higher than a stock motor should have been able to put to the wheels.

[mobythevan]

The website belongs to member "z-ya", we need to get him on this thread to address the state of his engine for that dyno. I noticed he has another dyno shot that shows full rpm range and shows 183hp, 211lbs. But I am sure he was continually modding between dyno pulls.

 

z-ya, you out there watching this thread........

[HIWAY ONE]

Stock 280zxt listed at 0-60 in 6.8 seconds

 

http://datsunzclub.com/specifications.html

 

Terry

[Drax240z]

So in a 500lbs lighter 240z... I need a G-tech!

[Guest bastaad525]

would/should be about .5 seconds faster 0-60 over the ZX, I would think. Maybe a bit less difference. The weight difference between my ZX and the 240 I have now is more like 600lbs. I want a Gtech too though I hear a lot of conflicting opinions as to how well they really do work. Stop watch is good enough for me!