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MAX HORSEPOWER ON A L28ET ??????


Guest Anonymous

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Guest JAMIE T

I wasn't really suggesting the SR20. That was just an example. Unless you've got about $12K and can speak pretty fluent Japanese, a DOHC L6 head is pretty much out of the question. One guy on this forum is looking into having a head developed. A cross flow design, though it will likely be SOHC. That is IF it ever gets developed. He is pretty commited, so it may happen, but it won't be cheap. And, no, the RB26 IS NOT based on or anything like the L6, other than it is an inline 6. kinda like sayin a Jimmy 6 is like a Datsun L6, it's not.

 

Yes, HybridZ does welcome you ideas and OPINIONS. But, saying that an engine swap would defeat the purpose of having an L6 in you Zcar is not what this forum is about. Plenty of us here have L6's, myself included. But, we all know there are better engine designs, and most of us would swap our L6 for one of them if we were no longer satisfied with the power production of our L6's. I for one would have no problem moving up to a RB26, or 2JZ if/when my turbo L6 became inadaquite. A SR20DET would be kinda side stepping in the power production point of veiw, but would offer a better power to weight ratio. BTW, our L series is based off a Mercedes Benz design.

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Guest Anonymous
I wasn't really suggesting the SR20. That was just an example. Unless you've got about $12K and can speak pretty fluent Japanese' date=' a DOHC L6 head is pretty much out of the question. One guy on this forum is looking into having a head developed. A cross flow design, though it will likely be SOHC. That is IF it ever gets developed. He is pretty commited, so it may happen, but it won't be cheap. And, no, the RB26 IS NOT based on or anything like the L6, other than it is an inline 6. kinda like sayin a Jimmy 6 is like a Datsun L6, it's not.

 

Yes, HybridZ does welcome you ideas and OPINIONS. But, saying that an engine swap would defeat the purpose of having an L6 in you Zcar is not what this forum is about. Plenty of us here have L6's, myself included. But, we all know there are better engine designs, and most of us would swap our L6 for one of them if we were no longer satisfied with the power production of our L6's. I for one would have no problem moving up to a RB26, or 2JZ if/when my turbo L6 became inadaquite. A SR20DET would be kinda side stepping in the power production point of veiw, but would offer a better power to weight ratio. BTW, our L series is based off a Mercedes Benz design.[/quote']

 

 

I understand where your comming from and nice to know were we both stand. As for finding alternate power well I'm rather unique. If I had it my way I'd develope a AWD V8 tranny that would fit a Z and slap a 427 with TWO well make it FOUR turbos. Yeah it would be heavy but hey it would be one in a milion.

 

~BB~

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Guest Anonymous
Max HP on MY L28ET = 0 :(

 

 

I'll get it put back together someday. :roll:

 

 

Jason

 

someday....................but no time soon

 

~BB~

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Guest Anonymous
Max HP on MY L28ET = 0 :(

 

 

I'll get it put back together someday. :roll:

 

 

Jason

 

 

Now thats impressive. :lol:

 

The sooner you put it back together' date=' the sooner you have boost.[/quote']

 

Yeah,my thought's exactly !

 

~BB~

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Guest DaneL24

Other than Don Devendorf in the early 80's...who else has put the serious big bucks and effort into making a 600+ HP L6? Thats the most I have heard of. I have heard "mentionings" of 800 HP L6 motors, but have never seen an article or any sort of material to back it up. To get there, I'm sure you would not only need all the traditional turbo mods (turbo upgrade, intercooled, big exhaust, etc) but also maximize displacement, head port size and cam profile. I'm sure that with enough porting and a good cam, a 2 valve SOHC motor can flow as much as an untouched 4 valve DOHC motor of the same displacement (Supras can make big HP numbers with a mild cam and little to no porting.) Maybe its pushing it, but everything just needs to be matched for a high powerband...turbo efficiency, port size, cam profile...and then maximize boost, displacement, and intercooling to get as much torque as possible at those high RPMs (Obviously have the low end to support the TQ and HP). Then I bet the L28ET (or maybe ported, cammed, and intercooled L31ETT in its highly modified state) could push some serious HP numbers to get up at least "close" to the Supras and such. Maybe.

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No way could an L6 get up there with the supra's. Not with any heads that exist in abundance in north america anyway. Sure, combustion chambers can be reshaped, pistons can be changed, ports can be ported, valves enlarged, etc. etc. But you still have the biggest flaw remaining: The L6 heads are not crossflow. This leaves you with big time heat going into your intake charge. I haven't done the tests myself on how much power this costs you, but I've read 11-18%.

 

ie: a potential 700hp L6 becomes a 574hp L6, which we have seen from time to time. (a few on this board are in the area)

 

I just reread and see that you are comparing with a untouched 4-valve motor... I'm not sure how well the stock supra head flowed, but I am sure it is comparible to a modified L6 head. However, the cross flow problem still persists!

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Guest DaneL24

Drax240Z:

 

So you're saying that the biggest flaw with a non-crossflow head is heat diffusion from the exhaust to the intake...so why not find a better way to mainatin low intake manifold temperatures? Why not use a heat shield with its own coolant flow and radiator...and then use a separate cooling system and radiator for the intake manifold. These are just a few ideas I pulled off the top of my head...there would be lots of ways to better maintain intake manifold temperature.

 

And as far as the existing 600HP L6s go...how far have they gone with their cams and porting? There are lots of people with turbos efficient at high RPMs, and cams that can't keep up at those RPMs...it just doesn't make sense! We need to see come L6 motors with fully ported heads, full race cams with 300 degrees duration, turbos that are efficient at 8000 RPM and well over 20 PSI (or twin turbo), better intercooling systems, and like I said, better ways to manage intake manifold temperature. And of course, bullet proof crankcases and all the fuel delivery to match. Sure it will be expensive, but it would still be a SOHC 12 valve L6 motor pushing some mega power. I know there are people out there with the money to do all this to an L6. Besides, the Supra boys are spending a lot more than just pocket change themselves...

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I'm not sure you understant the severity of the heating that takes place. Remember that the head is allready cooled by the radiator, and I am assuming that a great intercooler is used. You still have 1400F+ exhaust gas heating the head, and are trying to pass sub 100F intake air through it. Even if you lower your intake temperature to 80F with an IC/shielding on the intake/etc you still have a huge temperature gradient in the intake port to contend with. What I am trying to say is that changing the intake charge temperature by 20 or 40 or 60F isn't going to solve the power loss issue created by a non cross-flow head. (though it will help)

 

600HP L6's... well you'll have to ask the people that are doing them. 240z Turbo, jeffp, Timz, etc. (I know you guys aren't 600hp, but you're certainly better able to describe the challanges associated with that type of build than I am)

 

8000rpm is a problem too I think. Crankshaft dynamics just won't allow that type of speed with the loads subjected by a high compression turbo setup. If you start to get resonance, or beating in the crank at that type of speed and loads it won't last long. I suppose it is possible to get a "super crank" made from somewhere to withstand this speed and power, but at that point I think you'd be better getting a "super head" made instead. Maybe the diesel crank is significantly stronger than the stock L6 crank, but I believe the dimentions and material are similar.

 

What you are saying is feasible, an 800hp L6. But it would probably have a lifespan measured by a wristwatch. ;) It certainly wouldn't be as reliable as the old supra engine putting out the same power numbers.

 

Of course, this is just bench racing and really means not much in the grand scheme of things. ;)

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Guest Anonymous

I think a better question would be, is a ten second L6 car possible. Horsepower will only take you so far. Assuming the rest of the car is perfect do you guys think a well made L6 (nothing insane) could get into the tens?

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ive talked turbo setups with hoovers to a pretty detailed extent.

that car makes 400hp@14psi at the wheels on pump gas, and he could daily drive the thing if he wanted to, im thinking it has better manners than my car does, and my car is almost at the point that it drives like a brand new 280zxt, except no digital dash!. he has a pretty worked over head, that is obvious, but his cam is only a bump up from a stocker, makes all his power before 7k like a stock car with fuel upgrades, no lump in the idle that would tell you anything about its power potential. he does have many trick parts to his setup taht is for sure, most of them being in the bottom end of the car.

he doesnt have a 10k mile and die race motor either, if he stays at 400hp he could drive it every day hard for a long long time if he wanted to.

he could turn boost higher and run race gas and gets tons more power out of the setup, hes still making way more tq than hp at the 400level and undoubtdley can get more power, shoot the guy has a dyno in his backyard!

10s from an L motor isnt easy.

im working on a daily driver that will run low 13s with lazy launching and 6100 shifts on stock efi and a huge turbo, and if i finally bite the bullet and go standalone, i expect to be quite faster, how much, i dont know.

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Guest Anonymous

I have to agree about the Supra motors. I was an instant beliver when a guy running a dumpy looking 82 Supra with a 4th gen motor ran a 9.76 on ET streets and through mufflers.He told me the bottom end was stock and it dyno`ed at 1050 flywheel and 800rwh HP.The kicker was that He told me " the stock 4th gen Supra head without any portwork will support 1300hp".At that moment any dreams I had of competing in that class went right out the window.There are going to be some Nissan reps at the Next Battle of the Imports I should talk to them about an RB26....Ok a guy can dream...lol.

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One of the things I am really interested in is the ceramic coatings now available, and would they help with the temps created with a non crossflow head.

 

You are right about turning 8k, although perhaps you could make that easier by going with a 240 crank, but you loose stroke. I checked a long time ago, and if I remember correctly, the skyline engine has a 240 stroke with a 280 bore, or there abouts. Seems to me if you are set on turning one up, they going to a shorter stroke would benefit you.

 

James said something that seems to be going over everyone's head. The intake and exhaust ports only flow so much, and that is the limiting factor. Unless there is another alternative, you are stuck.

 

Right now I have an unported head, and am running a mild cam that is not much larger then stock lift wise, perhaps has more duration. The idle is good, and it chops every once in a while, although my idle mix is richer with this cam then stock. Don't know why, haven't really checked.

 

I am going to get my fogger running and see about letting JWT have the ECU control it. I think that will help.

 

As for a 10 second L6, there was someone in Cali with one, they used to feature it in Turbo, well I take that back, it was an early model z. There is some guy in North or South Caroline running 10's and James is really close.

 

We plugged JeffP's car in a calculator, which is bench racing, but it said he could run low 11's at about 124 if memory serves, on his old numbers. :shock:

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Guest Anonymous

If I could get exact specs on what needs to be modified on the L6 or if a new head needs to be constructed it is possible that my Dad could help build it. He's been a machinist for 50 years.... I'm not knowledgeable enough to know whats involved though, time to read up.

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As for a SR20DETT in a Z,well wouldn't that defeat the purpose of having a hopped up L series motor no swaps and such.

 

SR20DETT's don't exist.... there is an SR20DET.......

but no one makes, manufactures, builds or has ever accomplished an Twin Turbo SR20DE....

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Guest Anonymous
As for a SR20DETT in a Z,well wouldn't that defeat the purpose of having a hopped up L series motor no swaps and such.

 

SR20DETT's don't exist.... there is an SR20DET.......

but no one makes, manufactures, builds or has ever accomplished an Twin Turbo SR20DE....

 

Are you sure ? I'm pretty positive that I have heard of such a task been donequite a few times. Besides if someone can slap two turbos on a Spoon or Tec motor,I don't think a SR20 would be much harder. Unless there is something one of us is missing.

 

~BB~

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