Power

[The C110]

Ive been wondering this for some time, but never got around to posting it.

Ever since i learned of the S20 motors' existence, ive considered its power output. To me, the meagre 160hp that it put out was a little inadequate, considsering many performance motors of the s20 era produced double (and sometimes more) than what it could muster. Im vaguely aware of what it was up against in japan, but surely there were other jdm motors that outperformed it? Also, with just a few basic mods, a simlple l24 can be roused to produce the same power and more, for a fraction of the price. So my questions are these: Im aware that s20's can be tuned, but to what extent - they are a detuned race motor, so what were they producing in race trim - ie works 432r/kpgc10? Was the quoted 160hp output for all s20 powered cars a little 'conservative,' a la the ~274hp gentlemans agreement that stifled japanese performance cars throughout the last decade? And finally, did many s20 owners desire more power - were many s20's tuned? Do many tuned s20's still exist today? Hope to hear from everyone, regards,

Tom

[KGC210]

Don't know how much help I will be.

The 160BHP was the road version that was sold to the public.

The C10 GT-R's won 52 races so cant be a shabby engine realy.

I know some of them run about 240BHP in Japan but I don't know if they are street engines or full race.

Also they are mega dear to rebuild like £1k just for the straight cut oil pump drive.

Best person to ask about the S20 is HS30-H as hes rebuilding one for his Z432-R replica.

[Alfadog]

Great topic Tom, I'm interested too. Especially in regards to the Works cars... Watching the thread

[The C110]

Thanks KGC210, Lachlan.

I was actually hoping alan had something to add here...I guess we'll have to wait and see. Hmmm, Jim, any comments?

Tom

[g72s20]

...That's a good question Tom! I have a feeling the explanation to this is made up of lots of smaller details, but basically amounted to the development potential of the base engines into a reliable race motor. Remember, the S20 had the development(which amounts to time and money!) advantage over the L20, starting in 1965 with Sakurai San and his Prince Motors GR8 engined R380 prototype, through the whole R380 series of GT class race cars and culminating in the decision to place the S20 in what became the PGC10 Skyline (GT-R) of early 1969. I have an article in Japanese that I believe makes an attempt at explaining this very question, but I haven't been able to make enough sense of it to be sure. I'll dig it out again and take a fresh look at it.

I have been doing quite a lot of research lately (for very little result:disappoin ) into the early crossflow work of Sakurai and his team at PMC. The development of the single cam crossflow head setup on the Prince G7 motor, (GR7, G7CR and G7B...I think!?). These were tested in S54 Prince Skyline GT "mules". There is precious little info out there on these, and of course what is ...is in Japanese. The assumption is this work led into the R380 story and on to the S20 powered Nissan GT-Rs and Z432's....but I'm a nosey bugger and I want to know the details, the full story as it were. All I'm sure of is there were many and varied reasons why these engines were developed the way they were!!

Yours in Research

Jim.

[KGC210]

S20 specs for you:

6 cylinder inline. 24 valve. Double overhead cam. 'Crossflow' design. Hemispherical combustion chambers.

*1989cc capacity.

*82mm bore x 62.8mm stroke.

*9.5:1 compression ratio.

*3 x N40PHH Mikuni Solex carburettors.

*Electronic Ignition.

*6 branch stainless steel tubular ex. manifold.

*Power = 160ps @ 7,000 rpm ( red line 8.5k )

*Torque = 18.0kg-m @ 5,600 rpm

Quite sure these are the stock specs that the C10 and C110 GT-R's were sold with to the public.

Im also trying to find more info on these engines as well as the OS Giken Twin Cam heads for the L24 engine.

[g72s20]

Well......the article I referred to turned out to be this link-->http://carlife.carview.co.jp/User.asp?UserDiaryID=313631

I've tried using SYSTRAN on it, but now I'm less sure of what it is saying:stupid: Perhaps one of our Japanese reading friends (G'day Miles:D ) could put me out of my misery .

I know this is a little off centre to the subject, but with regard to the origins of the NISSAN "L" series, If I've read them correctly the various net sources I've read suggest the development of the L series (both 6 cylinder and 4 cylinder versions) was well under way within NISSAN before the merger with PRINCE Motors. What muddies the waters for me is references to Princes G7 OHC 2L six being the inspiration for the L series, and in turn, the Mercedes-Benz OHC inline 6 of the same era being the inspiration for the Prince G7. The Merc motor has its intake/exhaust on the other side of the head, but it certainly has its similarities. Those here familiar with the Prince Gloria S40 series may know of a story about Mercedes-Benz sueing Prince Motors over patent copyright for the anti-dive front suspension used in the S40? I don't know if this is fact or fiction, but over the years a few Japanese vehicle enthusiasts I've spoken with had heard or read of the same stories. A tenuous connection for sure..., but it would be interesting to know if these similarities in design were via licensing agreement of some sort or were simply a combination of "inspiration" and economic pragmatism?

Whoops!:tapemouth sorry to hijack, lets get back to the legend of the S20.

Tom, this is from that link, seems to be comparing a worked S20 with a worked L24. Wish I knew to what extent they were played with.

Promptly, 考えられる data everything such as vehicle weight and gear ratio 使って the lap time of Fuji 6Km with the computer 割り出した.

"S20" 253PS 8500min-1 21.94Kgm 6800 min-1 ﾗ ｯ ﾌ ﾟ ﾀ ｲ ﾑ 2 minute 02 seconds 37

"L24" 236PS 7000min-1 24.70Kgm 6800 min-1 ﾗ ｯ ﾌ ﾟ ﾀ ｲ ﾑ 2 minute 03 seconds 62

We've all seen S20's and L6's with the benefit of latter day hotrodding turning bigger figures than these, but I'm hoping the above numbers came from an engineering philosophy of a level playing field for each motor tested. I dunno! wish I could read Japanese

Cheers,

Jim.

[sakijo]

Well......the article I referred to turned out to be this link-->http://carlife.carview.co.jp/User.asp?UserDiaryID=313631

I've tried using SYSTRAN on it, but now I'm less sure of what it is saying:stupid: Perhaps one of our Japanese reading friends (G'day Miles:D ) could put me out of my misery .

I'm on it. My reading Japanese is not too good, so I'll have to ask someone for assistance. I tried SYSTRAN on it and it makes some sense to me, but I'll go ask anyway.

[sakijo]

This is what I gleaned from the article about the S-20 and L-24:

The Nissan Prince R380 race car was fitted with a GR8 engine. It initially developed just over 200PS or 197HP. After tuning, it improved to 255PS or 251HP.

The GR8B engine developed by Prince was re-designated the S-20 by Nissan and put into the KPGC10/PGC10 Skyline.

The predecessor of the GR8B was the GR7B, which powered the Prince Skyline GT-B. They did have a racing version of the GR7B, which had a cross-flow head.

In March 1971, a “racing type” Fairlady Z with a L-24 engine reached the “two minute wall” at Fuji Speedway. The calculated lap times were:

S-20 2:02:37 253PS (249HP)

L-24 2:03:62 236PS (232HP)

Although it is not stated, I suspect that the cars were both Fairlady Zs, the S-20 powered one being a 432R and the other being a 432R with an engine transplant. The article stated that the S-20 was quicker in the turns, but the L-24 had the advantage in the straights.

They eventually got 264PS (260HP) from an S-20 engine by enlarging it to 2200cc and reworking the head.

Sadly, the S-20 met its end due to stricter emissions.

So, what we’ve suspected all along is probably true. The street version of the S-20 is most likely an under-rated and de-tuned version of the racing engine. However, it doesn’t look like you could squeeze much more than 250HP out of an S-20 without major modifications.

Footnote: The article states that Nissan discontinued making the GT-R after the Kenmeri because the S-20 could not meet emission standards. It says that without twin cams, it could not be called a GT-R.

[The C110]

Its been a long time coming (from me) but thanks Jim and Miles, some great info there.

From what you have translated, Miles, my primary question was answered . It all makes sense, really, given that attempting to screw much more than 100-125bhp per litre from any NA engine is pretty difficult. Obviously the works race teams would have had a large budget at their disposal, but there is only so much you can do with two litres. With modern tuning techniques, as mentioned, more power would no doubt be possilbe, but it is interesting to see such a slim gap in raw outputs between the technically inferior l-series and the s20. I wonder if anyone has turbocharged/supercharged an s20...? Alan?