Datsun Roadster Forum-311s.org

After getting my 1600 running properly I am still not happy with the power and sloppy transmission. I feel like I am pushing it pretty good, when really I can hardly keep up with the soccer moms and minivans.

I considered stroking the R16, and U20. R16 - not much work, not much additional power without some head work. U20 - pricey. From what I see, rebuilt U20 and rebuilt 5 speed would be well over $7k and I still need to cut my tunnel for the shifter. But, it would be period correct, not numbers matching.

I searched for other powerplants. SR and KA being at the top of the list. Then I found the Ecotecs. The ecotec wiki has quite a bit of info. The latest gen 2.5l has the exhaust on the drivers side, 200hp NA stock, and no need for a fuel return line.
Not a lot of info on here for them. I read the thread with the guy that did it and the 311 member that posted pics. But I have questions that the thread doesn't answer. I read the others and still have questions as well.
Install pics
Ecotec Redux
This one too.
Ecotec Wiki

The transmission that bolted up to that motor for RWD was the Aisin AR5. Saturn Sky, and I believe the trucks. I read that the shifter lined up with the current shifter, but I am having trouble finding specs to confirm that. The manufacturer website doesn't have specs on it. It is supposed to be a little smaller than the T5.


Modifications would be:
Front crossmember
Trans mount crossmember for transmission and larger exhaust
Mounting ecu somewhere

Brakes - I have seen 300ZX, 4 Runner, Wilwood small. Others that are recommended?
Rear end - Not sure what to do about this one. I have seen people use RX-7 but they are a specific model.
Now, if I am doing front brakes and rear end, then I could narrow the rear a little more and put 5 lug axles. And, couldn't I also convert the front to 5 lug? Now, more wheels become available. I suppose it depends on which front brake swap I use.

In tank fuel pump required?

New larger radiator? Or do you think the aluminum replacements would do?
Tunnel need enlarging?
New gauges too.
I am sure I am missing other issues.

The rabbit hole gets pretty deep when you say "well, as long as I am here..."

I would love to be able to ask the guy that did one.

Thanks.

Yes you would need /want the fuel pump system off it in that tank ...would be easiest.... if it fits
Lot of wiring , trans works size wise etc. ?

My friend is in the midst of doing an Ecotec swap , it’s a long story with a few twist but he basically got a crate engine from GM for free
But even with a free engine and that is doing a lot of the work himself he will be well over 10K when the swap is done with all the mods required. Granted he’s doing a turbo but still.

You say you want more power but not how much is it just a little to make fun or tire scorching stupid power ? Being that you’re in central California you have access to many roadsters I would connect with people in the area and drive/ride as many as you can to make up your mind of hat you want then decide. I had to fly to CA to do this

After doing lots of research I came to the conclusion that while I I like swaps a well built U20 was going to be perfect engine for me and the least cost since everything would be done by someone else. for my other car I have an R16 with lightly over bored pistons (.30) , a P&P head, a cam and LW flywheel that car is lots of fun will cruise at 80mph all day long (it turns at 4K rpm at that speed because of the 4sp and small tire but that’s an easy fix ) it will also spin its tire on 1-2 and 2-3 shifts (see video)

Last if I was to do a swap I would consider them in this order
Miata NB 1.8_ No cutting fairly easy and an honest 140whp with a few bolt ons
KA24DE_ My favourite very little modification required , a torque monster
SR20DE_ great power super fun engine, More complex but has been done so many times it could be argued that it’s probably fairly easy given the support

Best of luck whatever you do and ask lots and lots of questions

R16 spinning tires

That is a good point. Perhaps I should ride in some that have alternative powerplants.

The allure of the 2.5 (LCV) is the good amount of NA power and the exhaust is on the correct side compared to the earlier Ecotecs. They are readily available as is the AR5 transmission. The question is: will they fit without requiring an extreme amount of modification.

Slackline wrote: Sun Nov 01, 2020 11:03 am That is a good point. Perhaps I should ride in some that have alternative powerplants.

The allure of the 2.5 (LCV) is the good amount of NA power and the exhaust is on the correct side compared to the earlier Ecotecs. They are readily available as is the AR5 transmission. The question is: will they fit without requiring an extreme amount of modification.

Oh ok you’re talking about the later 2.5 that came in the Cadillac ATS, that thing is huge much taller than than a KA I’m sure
I remember it being tall because I noticed that when I was buying my ATS Coupe and was checking the engines you could see it took more room in the engine bay compared to the 2.0T (which I got ) the 2.5 took almost as much room as the V6

I would expect lots of fabricating to make it fit and the fact that the exhaust is on the driver side doesn’t make it any easier as you still need to deal with the steering column that’s there

"I considered stroking the R16, and U20. R16 - not much work, not much additional power without some head work. U20 - pricey."

While you will have to put in a little more work/$$ to get a good increase in power from a stroked R16, the power increase can be significant. A power increase of 30 to 40%+ is not hard and very noticeable.
Headwork - 34 mm exhaust valve, minor port cleanup (intake and exhaust) will do the trick. Nothing major really needed.
Cam - choose to match your airflow, compression ratio and driving habits. approx 220* - 225* duration @ .050" and around .450" valve lift.
Exhaust - 1 1/2" header and minimum 1 3/4" (2" might be better) exhaust system, free flow muffler.
Carbs - DCOE's or U20 SU's or...? If the above were done the stock SU's would become the choke point.

Maybe you should check with Rebello to find out some prices for a built R20. Dean just posted a stroker dyno @ 180 hp.

Unless you are doing a lot of the work yourself, the R16/U20 options will be the most cost effective.
IF you just want to build the car to your own specs, have at it.
FYI with a bit of 'tweeking' the KA24DE is quite capable of 200 HP N/A.

I agree with Daryl. Regarding thd KA, they made a dual carb (Mikuni, Weber, Dellorto etc) intake manifold for the KA 12 valve that would allow you to really keep the mods simple (no EFI pumps/mods etc).

Never underestimate a soccer mom, some apparently are packing nitrous....

I do have one of the KA-e dual carb manifolds and a bunch of KAe stuff I'd sell.

The KAe swap is not as easy as the KA24DE since the KAe oil pump is in the crossmember - that means a frame hack. Otherwise it is similar (transmission and clutch is the same as DE, gauges don't work, alternator position issues, 240sx variant distributor won't work and the truck distributor is a smog design and most ran TBinjection with a primitive ecu, 240sx version was EFI, but not a great setup-DE was much improved)

The truck variant is exactly what you would expect-go test drive a 80's 720 and prepare to be massively underwhelmed lol.

Don't expect huge HP from a KA (e or de) They don't like to rev without a lot of work - they do make very good torque, so they can be very fun street engines. Just like anything, it costs money to have a good result. All the KA's are emission engines too, that stuff all needs to go for tuning, and may create an emissions issue for you depending on where you live.

Also, The KAe manifold for webers is just one very ugly lump of aluminum, so linkage will be a PIA. (sounds easy, but if you build crappy linkage it will torment you forever)

I'd say SR,KA, CAt, stroker, U are all better fits/choice than an ECOtec. CA's are neat motors and very compact, but most used ones have had the life beat out of them, so they need a full rebuild. That's the case with many SR's and KA's too-worn out - road hard so to speak. Junk yard motors are always risky purchases.

Wasn't there an aborted SR project listed here somewhere recently?

I also have lots of SR parts, but most the SR engines are torn down for rebuilds since they were worn out DET engines. Also have a few partial DET rebuilds in process if you want to spend crazy money on your swap.

Too bad about the KAe. I remember seeing a 240sx blowing the doors off of everyone, including V8 Corvettes, at a local track. Later, I was surprised to spot a NA 12 valve with dual Mikuni carbs on it. Clearly a race motor, but still very impressive none the less.
I was gonna mention the CA18 as well.

The KAe is not impossible, its just like the L-series with the protruding lower oil pump. Nissan revised the front cover with the DE, so with the DE you don't have to hack up the crossmember-much easier.

The stock KAe is a very mild motor in standard trim. Hi-performance versions are possible, its just like any race engine build $$$$.

The twin cam makes more power all around (improved port injected EFI with CAS and ecu) so that is another reason most folks use the DE.

Turbo versions of the KA tend to grenade, so if a turbo is needed, the SR is the better engine.

Well, I may have found a deal breaker for the ecotec. The ecotec wiki only has the regular ecotec measurements. Per the GM Powertrain website, the LCV 2.5 is apparently redesigned. Under 24" from the front of the crank bolt to the back of the head - fine. Width also looks ok. But the height from the bottom of the pan to the top of the oil fill cap is 27.6". I think that is pretty tall. I'm not sure how much room there is from the top of the R16 to the hood, but I doubt it's that much.

Does anyone know how tall the KA24DE is? From oil pan to top of valve cover (or highest point on engine).
I have searched online. Many sites with "everything you need to know about engine x," except it is missing the physical dimensions.

Also looking for height of the Miata NB 1.8 setup. Same problem there. Many website users have asked and someone will say "I'll measure it tonight and post", but the thread ends there...

I was able to find unverified measurements of the Honda K20 at 25" and the K24A2 at 25.5".

I Look in the next couple of days!

matt

I pulled my R16 stroker and replaced it with a U20. I get 25 1/4" from oil pan to oil filler cap on the R16. Hope this of some help to you.

Thank you.