l28et vs sr swap battle ! but this ones hard

[subtle_driver]

arn't xflow heads like 40 year old plus technology?

 

like back in 1969 nissan was using a xflow head for the fairladyz, but many racers didn't like them because they didn't put out enough power compared to the sohc.

 

and tell me how much tq this 200hp honda motor has! is it 150ish?

[majik16106]

I wouldnt say 100% all the time the turbo engine is the best bet JUST because it was built for a turbo. And of course every argument being made here inherently carries some assumptions. Can he source a backyard kit cheap? does he have the motor? did it come with it? is it 600hp, 400hp, or 1000hp? road racing or drag racing? thats how these arguments always break out, someone offers up some blanket statement that pisses some other guy off and the world lets loose with pricing breakdowns and my brother did this and I have an engine that works better and etc etc. The point is NOT that an sr is better than an l28et or that a KA is better than an SR, the point is.. The SR is better FOR HIM. or the L28et is better for him. and then we give our reasons. its ok to have a different opinion. Its like trying to choose a wife for a man, I think he should go with Cindy for this and you like Sarah for that.. well truth is if he could live two lives he may end up blissfully happy with both, so niether of us is wrong, we just choose based on different sets of criteria. its good to offer up those sets without arguing between us so that he can make a decision based on our insights. because of our insights were the same... then he wouldnt need both of our insights.

 

So i could make arguments that the sr provides better weight than an l28et, which is free lots of things, the engine comes with better pistons, a better rod ratio for revving the piss out of it, the electronics to handle a 300hp set up with just a boost controller and safc/ power fc. and that the added torque you would have from a ka24 is mute compared what typically would be a much harder engine to modify and run at 300hp. that being said.. if i wanted a 500hp road racing car.. i go Ka because the extra displacement, i have to upgrade the sR anyways all around so might as well do it with an engine you can get pretty much for free with more displacement and the electronics dont matter since your pretty much doing SA anyway. oh wait.. you want a street car with 600hp, well go l28et. build it up 3.1 turbo stroker. the torque will be phenominal fun on the road. fast as hell, not too expensive in comparison to swapping in another turbo inline 6. etc etc.. see where im going?

[Gollum]

majik, I agree completely. I've said many times on these boards that almost every engine has a home in Z, depending on the owner. It's all about what you want in the car.

 

 

Back to the crossflow topic....

 

Ok, wow, a honda engine can make 200hp, with about 2 liters. That's why I said a worked Z head can make 300hp NA with reasonable reliability. Sure the honda head can be ported and work to make even more power, but in keeping with the comparable valve and port sizes it wouldn't be making much more power per cubic inch than the nissan L6 can make.

 

The main reason modern cars are all crossflow is WAY MORE about the logistics of the layout of an engine. It just doesn't make sense to have the intake and exhaust on the same side, it takes up too much room for how compact they make everything now days. This is why companies like jeep kept their non crossflow heads for so long, they had large vehicles with plenty of room and they had a system in place that worked, so why change. When it came time to design new engines the went crossflow, and designed new chassis around that layout which made for a more compact package.

 

You're thinking logical, but not practical. Sure a non crossflow head has less room for ports, but in practice the ports don't need to be so large. They only need to be about .6 the diameter of the valve (iirc), and there's plenty room for both in the space of the head. In fact, both valves fit inside the space of the chamber just find, in theory you could fit a port the diameter of each in a non cross flow head, but that would kill velocity. What matters more than anything else is how much room you have to port right at the end of the runner, and at that point it doesn't matter if the head is crossflow or not.

 

Things like valve guide design have a larger impact on performance than weather or not a head is crossflow.

 

There's lots of discussions on the topic on this board, and trust me, most of those around that actually port heads and reach high HP can talk on and on about what the real limitations are in head porting. The fact that the head isn't crossflow rarely ever leaves their lips, and it's usually just when others have brought it up.

[whitechocolatelove]

majik you just saved us all from more confrontation thank you very much!

[SmogSUX]

Whoever said noone would want a sohc ka24 motor...hahahaha I'll take any sohc ka if you're local. They respond so well to boost.

 

I have one friend who completed a turbo install and tune on his sohc and he puts down 320 rwhp with stock internals. Still beating on it.

I have another who put down 220 rwhp at low boost with a z31 turbo and his total cost for the turboing of his car is at about $500.

And another who's still putting his turbo kit on. He's opting for an S15 turbo he found for cheap.

 

Then I have one dohc Ka buddy that put down 350rwhp with a pieced together turbo kit, meth, 20g turbo, tuned ecu, safc, etc..STOCK INTERNALS BABY!!

[logr]

I'm curious. How do you stop the KAET lash adjusters(can't really call them lifters) from rattling like crazy every time you rev it at all? Mine ran ok but the rattling drove me crazy and once I had an SR, I never looked back.

[subtle_driver]

I'm curious. How do you stop the KAET lash adjusters(can't really call them lifters) from rattling like crazy every time you rev it at all? Mine ran ok but the rattling drove me crazy and once I had an SR, I never looked back.

 

 

doesn't the sr have those lifters? I think of an sr, as a destroked ka24e with 1 extra exhaust valve, with weaker aluminum block. ok im just pushing buttons.

[subtle_driver]

I'm curious. How do you stop the KAET lash adjusters(can't really call them lifters) from rattling like crazy every time you rev it at all? Mine ran ok but the rattling drove me crazy and once I had an SR, I never looked back.

 

what you had was most likely "timing chain rattle." the upper timing chain guides are deleted and the noise goes away. The fwd SR20 in Sentras at least have a simular problem. or maybe the oil was low or the engine had internal damage from lack of maintainece. my stock ka has been revving to 7,800 rpms for years without problems. the ka24de has the same type of valve train as the RB26. the sr has rockers, like the older L-series and Single cam ka, they tend to pop off when revving. Think of the KA24de as a 4-cylinder stroker version of the RB26. Or the RB26 is a 6 cylinder-destroked ka24de? lol

[True School 240Z]

I've had a S30 with a L28ET in it, and now I have another S30 with the SR20DET in it. Both are great. I'd recommend either. The SR seems to be a little more economical on fuel consumption however.

[frank280zx]

All L's i blew up where MY fault.. I modified everything EXCEPT !!! the oil pan making it starve in coners throwing rod bearings.

Edited April 26, 2011 by frank280zx

[Zguy91]

"BTW, the stock mass air flow sensor from a single cam ka24e is the same one used with the sr turbo engines."

 

This is not true. It is close but its not the same. If you have ever looked at the mapping for both the single cam MAF and the SR MAF they are not the same but similar. The SR will not run perfectly using the single cam MAF

[69sroadster]

I agree about the MAF differences. First fire up on the SR proved that out for me as it kept dying after a couple of seconds. Swapped to an actual SR MAF and it's been running fine since then. The other MAF I am 99% sure came from a KA my brother accidentally confused for me when he gave it to me.

 

I love the passion everyone has here in the discussion. It seems we can all do great things with some patience, advice, time and money to whatever motors we want. I opted for the SR because it was lighter and gets better gas mileage and I was familiar with it. I guess I could have gone KA too saving cash, but at the time I wasn't as familiar with it. It was a fun learning experience doing the SR and I still think the torque in it is just fine as it is. I've had it in for 4.5 years now, been to 14+ autox events and a recent Hallet HST event. The A/C works and it gets over 30 mpg on the highway in my 2+2 ZX (3.7 rear gears & 255/40/17's). It makes me smile, and that's all I need. To each their own. Whatever you choose, I hope it can make you smile too.