SR20DE fans--exactly which engine/tranny combo is the best?

GoldHawg · Post by **GoldHawg** » Sat Sep 02, 2006 8:33 am

I see a whole bunch of different sr20de's for sale on ebay, some FWD some rwd, some w/auto, some w/stick. Some 5 speed stick, and some 6 speed stick. Some are early 90s, others in the early 2000s. What is the best combo to buy in terms of ease of installation, and fit in our roadsters? If it would work, this one looks like a pretty powerful combo:
http://cgi.ebay.com/ebaymotors/SR20DE-M ... 3272QQrdZ1
Appreciate your comments.

Dave · Post by **Dave** » Sat Sep 02, 2006 9:37 am

That's a pretty sweet looking deal. You most likely won't be able to use the header (steering column fitment issues) but could probably turn around and sell it to someone else on E-Bay. Also, IIRC, the 6 speed requires a LOT of modification to the X-member. Much more so than the standard 5 speed. We need some input here from Mr. SR20 guru Michael. I'm wondering if you can simply bolt up the S13/14 5 speed to this S15 engine. That would make your swap a whole lot easier and I'm sure you'd come out money ahead by selling the 6 speed.

GoldHawg · Post by **GoldHawg** » Sat Sep 02, 2006 9:52 pm

I called the guy up and he said he had all the stuff to change over to a 5 speed for the same price. So if I actually did something crazy and bought this I'd probably have him switch over to the 5 speed. He said that all the sr20de's are dimensionally the same, that beginning w/S14s they went to VVT. So my question remains, anything when looking for the engine to stay away from?

Thx!!

spriso · Post by **spriso** » Sun Sep 03, 2006 12:47 am

Here are the answers to your questions:

1. Are there any combos to avoid or specifically go for?

As long as it is a RWD version of the SR20DE engine, you are good to go! I would look at the S14 or S15 versions as they have more horsepower than the S13 SR20DE, but any of them will work nicely.

2. I obviously want a stick, but can you make an auto engine work and pick up a tranny separately?

Yes, that is easy to do. You will have to modify the engine wiring harness (I can send you notes on that), and remove the bushing for the automatic flex plate from the back of the crank shaft, as well as source the longer flywheel bolts for the manual transmission flywheel.

3. Will the 6 speed also fit thru stock tunnel? Would this be a good combo to get?

We recently finished our first 6-speed conversion on a roadster, and I must say the 6-speed was worth the effort! I originally thought that the 6-speed would be busy (as it adds a gear between 1-5th gear), but it reality it lets you be in the right gear at all timesÃ¢â‚¬â€it really makes the car even more fun to drive!

To put a 6-speed (behind a SR20DE engine) you need the 6-speed specific clutch, flywheel, starter, transmission, and driveshaft as they are all different than the 5-speed stuff.

The transmission tunnel needs to be modified on the passenger side to clear the larger bell housing and center section, and the X member on the frame needs significant modification to fit the gear box.

If you are up for that much work, it is well worth the effort! If you are not looking for even more fabricationÃ¢â‚¬â€then skip it and put the 5-speed in.

Since the auction you are looking at is for an Autech version of the S15 SR20DE engine, it already comes with the 6-speed and all the trick parts that are associated with the king of all normally aspirated, RWD SR engines.

The Autech engine makes 200ps (~198hp!), but it does it by cranking up the compression numbers (as well as the cool cams, valve train, exhaust header, etc.)

It is the compression numbers that makes the Autech engine a tough sell thoughÃ¢â‚¬â€it runs 11.7:1 compression, so you better be able to put good gas in it, as it wonÃ¢â‚¬â„¢t be happy on regular stuff coming out of the pump!

I have a couple customers that run (or will be running) this engine, one uses his car as a track car only, and he puts race gas into it, and the other is hoping that he is going to get by on running a conservative tune and premium gas (we get 92 at the pump here in Oregon) to make his engine live.

If you can live with that, then the Autech engine is a great way to goÃ¢â‚¬â€or you could always put a lower compression set of pistons into itÃ¢â‚¬Â¦ but there goes your HP advantage!

That is my .02 Yen, spend at willÃ¢â‚¬Â¦

Michael

GoldHawg · Post by **GoldHawg** » Sun Sep 03, 2006 7:53 am

Thx much! I am not interested in more fabrication work, but rather want to hit the "knee in the curve" where you get the most bang for the least buck (both in $$ & time). Sounds like the S15/5 speed combo is the way to go (not the Autech version). Haven't been able to find a good write up on all the engine variations but believe the s15 (non-autech) puts out 160 HP,which ought to be plenty for me, yet still run on regular gas.

buzzardmountain · Post by **buzzardmountain** » Mon Sep 04, 2006 6:50 pm

How about using 93 octane, would that work?

GoldHawg · Post by **GoldHawg** » Mon Sep 04, 2006 8:05 pm

Also, I have some concerns about the autech version, since its the specially "tuned in Japan" version. What happens when you make changes? For instance, I have been told that stainless header won't clear the the steering column shaft. So if I go to a smaller header will it need computer work? Is that hard to get on this rare version? Overall, how much reprogramming of the computer is necessary on regular SR20DE swaps? since I am new to this scene, are there lots of sources that can do that (if its even necessary)?

nomadtrash · Post by **nomadtrash** » Mon Sep 04, 2006 10:41 pm

It would probably make slightly less power with a standard manifold. Tuning could help but the motor would probably run just fine on the factory computer with a different manifold. If you are concerned about getting the last little bit of power then there are several options.

Unless you are going crazy with turbo boost you can tune quite well with an Apexi SAFC and some sort of wideband setup like the techedge, aem UEGO, Innovative, etc... I'm using a bikirom which is cheaper than the Apexi. It is a programmable fuel injection computer that can adjust every aspect of the ignition and fuel. You can load the base settings for your motor and then tweak until you get it tuned well. This tuning is most effective when done on a dyno with a wideband. The bikirom will datalog every parameter and you can replay the data like a tape recorder. You can choose to look at the oxygen sensor, rpms, fuel injector cycle time, and the throttle position. Based on the oxygen sensor readings at any given rpm and throttle position you can increase or decrease the fuel injector pulse time to make it richer or leaner. You can do the same with the ignition advance.

Like I said, the Bikirom is great to fine tune the motor but for best results you should put it on hte dyno.

The Apexi SAFC intercepts the mass airflow signal and retransmits it to the computer. It also gives readout of the injector cycle time. By adjusting the signal that the SAFC transmits to the computer you can trick the computer into giving more or less injector cycle to make it richer or leaner. The SAFC has limits to how much tricking it can do. It also does nothing for the ignition timing. Some guys run turbos and can get decent results with the SAFC up to the 300 horse range. This tuning can be helped out with a wideband setup but the inability to datalog only gives you a general idea about where it is running rich or lean.

Another option is to have ENthalpy or JWT do a custom tune for your computer. They would do all the tuning necessary. Enthalpy tends to get more power from his tuning. JWT is more conservative.

spriso · Post by **spriso** » Tue Sep 05, 2006 11:19 am

How about using 93 octane, would that work?

Yes, that will help, but remember, the Autech engine is tuned for Japanese premium gasoline which has a much higher octane level than the premium gas we can buy here in North America.

So if I go to a smaller header will it need computer work? Is that hard to get on this rare version? Overall, how much reprogramming of the computer is necessary on regular SR20DE swaps?

You can use the stock ECU and wiring harness on most SR swaps without having to have them re-programmed. However, there are a few setups that will require a re-program as the computer will look for a speed sensor signal that in some cases (depending on your instrumentation) may be missing.

One of my customers, who runs the Autech engine in his Datsun 510, is running an unmodified computer, and the car works very well. He tried to match the stock Autech specifications as much as possible, but only runs race gas in his car.

The Autech SR20DE powered Miata that we are building right now did not come with the factory wiring harness or computer. I modified a S13 (240SX) wiring harness to make the engine run, and we sent out the ECU to Jim Wolf Technology to have the S13 ECU modified to run the Autech engine. JWT has an 11.7:1 compression ratio program that is tuned to run 92 octane gasoline.

Since this is a little more conservative tune, we will loose a little horsepower, but hopefully it should be run safe on the street using premium gasoline from the pump.

When the car gets on the road, we will be taking it down to JWT to have it tuned on their dyno, and Clark can make any changes to the ECU so the engine will live on pump gasoline.

So the question becomes, are you willing to do the extra work to take advantages that the Autech engine/transmission has to offer? (Such as rebuilding the X-member and transmission tunnel for the 6-speed, building a 2.25"- 2.5"exhaust to match the 60mm exhaust that came with the car from the factory, etc.)

If you are not going to take advantage of the cool parts that the Autech engine has to offer, then it really makes more sense to find a S14 or S15 SR20DE engine with the 5-speed transmission and get the car back on the road much faster...

BTW, I drove the S15 SR20DE/6-speed car last night, and trust me; it has more than enough power for the chassis!

Michael

GoldHawg · Post by **GoldHawg** » Tue Sep 05, 2006 9:27 pm

Well the autech sold to someone else anyway. Michael--do you have any recommended sources to purchase the S15 sr20de from? Or should I just continue to scour ebay?

thx!

spriso · Post by **spriso** » Tue Sep 05, 2006 10:09 pm

Since you are in California, I would give these guys a look:

http://www.sr20store.com/

Get a quote on a S14 SR20DE or S15 SR20DE with 5-speed transmission...

Don't forget, I have engine mounts and alternator mounts for the SR20 swap for sale if you don't want to build your own!

Michael
spriso.motorsports

GoldHawg · Post by **GoldHawg** » Thu Sep 07, 2006 11:16 pm

please forgive an ignorant ?--which cars w/sr20de's were originally rear wheel drive (I'm not into late model japanese cars--this is my effort to get back into rice rockets). Thx for educating me.

Dave · Post by **Dave** » Fri Sep 08, 2006 11:27 am

which cars w/sr20de's were originally rear wheel drive

In the US, none. We only got the front wheel drive version of the SR20DE. In the rest of the world, the Nissan Silvia (what we know as the 240SX) got the rear wheel drive SR20DE. The Nissan model code for the car was S13, S14, and S15. That's why you will often hear of the engine itself referred to as an S13, S14, or S15.