PDA

View Full Version : dohc or sohc?



DefeXion
02-07-2007, 09:18 PM
As everyone probably already knows, that STR is a sohc. I was inquiring around various second hand parts dealers and found some mitsuibishi diamantes which had 6a13 n/a dohc engines. They are going really cheap as they are off a test series of the diamante and don't really belong to any car.

My question is, would it be worth trading in the sohcy in the str for a dohc? What differences would you expect when driving on road. torque, power, stuff?

btw, to anyone who might be interested in a toy engine. they are 1000 dollars a piece for the full engine assy from kempys in auckland.

bradc
02-07-2007, 09:27 PM
I know about those engines, I was seriously considering getting one of those and putting it into a manual STR before I found my white VR-4. I would expect there to be some power gain, whether it is going to be worth it or not is something I'm not sure about. If you did that and got a manual conversion, I would be happy to swap my white VR-4 with your car any time!

Catalan
02-07-2007, 09:28 PM
in Japan Legnum STR 2,5 have a dohc 6a13 engine
and 175 horse power

6a13 sohc and 163 hp have only europe version, or it my mistake ?

DefeXion
02-07-2007, 10:08 PM
Are you sure? I will have to check that. I was under the impression all the japland strs were sohc. Following specs sheet from kong kong galant club

http://www.hkgalantclub.org/update/html/spec.php

The dohc may provide more tuning options. Get more air in there and customise intake/exhaust timing, air/fuel to suit.

Here's a followup question then. Would a dohc engine run on a sohc computer? 1000 bux for the engine is probably going to be the least cost in changing over methinks.

Subaru ETA
02-07-2007, 10:48 PM
how bout buy a vr4? i take it you would be paying someone to do thhe work anyway a nd you can get some pretty cheap vr4s on tm

bradc
02-07-2007, 11:23 PM
Catalan - the V6's have two cams, one on each bank which makes the sohc, while VR-4's have 4 cams, two on each bank. Due to the confusion some people call the 6a13 non-turbo engines dohc, but they are most defiantely sohc.

Defexion - your current ecu will almost certainly handle it. If it doesn't then you can use an FTO Mivec ECU. Kempys should be able to give you more details about the ECU situation.

DefeXion
03-07-2007, 12:25 AM
how bout buy a vr4? i take it you would be paying someone to do thhe work anyway a nd you can get some pretty cheap vr4s on tm

Considering it definitely :). I was keen on the idea of the n/a dohc since it doesn't have any turbos. And being from test cars, they are low k's. If I could find a good condition VR4 for the right price, I would definitely prefer that. Insurance will be a killer (18yo and all).

Either way, I want to do the engine swap for my own learning. I have some hookups for getting the work done, but I would prefer to try myself.


your current ecu will almost certainly handle it. If it doesn't then you can use an FTO Mivec ECU. Kempys should be able to give you more details about the ECU situation.

Cheers for that. I use to be well acquainted(sp) with Chris McDuffie at Kempys, but I have been told that he left. 'Tis a sad day for all :(. Chris was a legend.

bradc
03-07-2007, 02:30 AM
Chris was the guy that owned the 2.5l 6a13 dohc n/a FTO wasn't he? I've spoken to him before, as above I was looking at buying an ST-R and getting the dohc engine in there :)

Catalan
03-07-2007, 07:48 AM
Are you sure? I will have to check that. I was under the impression all the japland strs were sohc. Following specs sheet from kong kong galant club

http://www.hkgalantclub.org/update/html/spec.php

The dohc may provide more tuning options. Get more air in there and customise intake/exhaust timing, air/fuel to suit.

Here's a followup question then. Would a dohc engine run on a sohc computer? 1000 bux for the engine is probably going to be the least cost in changing over methinks.

Yes, 2,5 STR is a SOHC :(
but vr-4 :)))) or VR-M with 6a12 MIVEC %))))

DefeXion
03-07-2007, 08:23 AM
Yup, VR4's are definitely DOHC.

Haha, imagine an ST-R with two hairdriers on it. I wonder how much good they would do.


Chris was the guy that owned the 2.5l 6a13 dohc n/a FTO wasn't he? I've spoken to him before, as above I was looking at buying an ST-R and getting the dohc engine in there :)

I'm not sure what car he drove. I saw him on site rarely. Most of our communication was for business purposes. He was always a laugh though. A 5 minute order could easily turn into a 10 minute ramble about nothing.

zentac
03-07-2007, 08:34 AM
As far as I know Kempys was the only place that had these engines, they had 3... sold one to RPW, fitted one into their FTO and I canabalised the other. Have you found somewhere else that has them?

DefeXion
03-07-2007, 08:37 AM
They imported about 15 (maybe it was five, I didn't quite catch what he said) more of the test diamantes as far as I know. All with engines that belong nowhere :D

It's still a hard decision. Is it really worth getting the dohc engine? Is it really going to be easier to get more power out of? Should I just get a vr4 engine instead? gosh, I don't know anymore :P

mpau009
03-07-2007, 09:23 AM
I would fully recommend dumping the STR in favour of the VR4, i got rid of my STR after 2 years, and its the best thing iv done. Running costs go up, somethings always breaking, but its the easiest 100odd HP gain you can ever get. Carsten (Gly) did the same, even though he put a huge amount of work into his STR, and i bet he will say the same..

As for me, i upgraded a month before my 21st birthday, and my insurance went up by $50, didnt know whether to be happy or annoyed:thinking:

bradc
03-07-2007, 09:57 AM
I still maintain that if it all ends up working properly with a manual gearbox, I'll swap the car for my white VR-4 :)

Gly
03-07-2007, 09:58 AM
yes i will...

my ST was at the stage where i either had to invest a heap more $$ and convert to manual, and turbo, but in the end, it wasnt worth spending more money on....

this is how far the ST got before i cut my losses... its the GFs ride now.

http://www.clubvr4.com/forum/vbpicgallery.php?do=view&g=36

i decided to buy this and transfer the parts i could...

http://www.clubvr4.com/forum/showthread.php?t=22753


and if i can get insurance with my driving record, anyone can...
try mobile insurance consutants.


and for the money you would spend converting and getting it all working right...
you would swap for brads auto vr4?

you might aswell sell what you have now a buy one. save yourself the trouble.
and have left over cash to put on a couple of power mods on the vr4.

DefeXion
03-07-2007, 10:35 AM
then I have the problem of it being financed, ugh. THERE IS NO WINNING. lol.

so VR4 asap then rather than pouring more money into the leg. I can see perfect reasoning in that.

Gly
03-07-2007, 10:40 AM
you can still trade it in, its not much of an issue unless you just bought it and you still owe more than its worth as a trade.

DefeXion
03-07-2007, 10:46 AM
Well I bought it for 13 at 60,000k's (It was a demo car for dolphin aeroform in japan I believe).

The balance currently stands at 9g I think?

Gly
03-07-2007, 10:51 AM
yeh worth less as a trade than what you owe on it,

keep it till you paid it off,

maybe covert it to manual...
only if the auto dies or if you get the parts real cheap,(sub $500, pick-a-part) and can do it yourself.

then sell it or trade it once its paid off,

instead of wasting thousands of dollars converting to dohc for very little gain imo...
put that money into paying lump sums and getting it paid off quicker and save yourself some interest charges.

DefeXion
03-07-2007, 12:29 PM
Sounds like a plan. I still want your cuscos though :).

Subaru ETA
09-07-2007, 12:16 PM
also you have to think of what happpens when something goes wrong with the 6a13 n/a dohc...are the parts the same as on other engines?

i thought my str was a great car...until i got the vr4! you would never look back

DefeXion
10-07-2007, 02:52 AM
I want a vr4 really badly now :(

Nobody seems to want to swap an VR4 for an STR... I don't know why, but it is making it difficult. This may be a sell first then buy situation unless I goto a dealer.

Subaru ETA
10-07-2007, 04:10 AM
this is why i always pay cash for things. now you are over the cxar but cant sell coz you still owe too much money!

for a trade you will prob only get $4000 for it.... well that was what every car yard offered me till i got one yard to offer me $7500! but that was coz one of the dudes daughters saw it and wanted it so yeah.

just dont rush, look around and see wat people will offer for yours.

bradc
10-07-2007, 04:44 AM
I told you I'll swap my VR-4 for your STR, but only if you convert it to manual first!

DefeXion
10-07-2007, 07:29 AM
how many k's? Is it manual? and can I swap out the leather, wheels and bodykit :P

Gly
10-07-2007, 07:43 AM
lol its an auto! why would you want it?

bradc
10-07-2007, 07:46 AM
135km, it's auto, and my car has black leather too, so no swap needed! I'm also happy with my wheels and don't want the bodykit, so yeah it's all good.