"Erickson, Philip" wrote:
>
> I would vote for a 4 cylinder, if all you want is 200 HP. The Nissan
> choices I looked at were the SR20DET and KA24DE. The KA would be the
> easiest, you can buy a kit. I would prefer to see the SR as there are not
> many conversion in the US, but you have to cut the front cross member. It
> appears the cross member is plenty strong. BTW, I decided to stay with a
> U20 until I see a few more completed conversions.
The SR20 or an FJ20 would be my first choice in that hp range (turbos of
course). Les has a line on some complete, almost new, super-low-mileage SR20DETs
from the current Silvia. They are turn key (they are supposed to be complete and
ready to run no extra parts needed) and they include the *6* spd tranny. I have
ridden in the new Silvia and I can tell you this is strong motor (~250 hp) that
pulls well from idle and has lots of top end too. I was very impressed by the
powertrain in the Silvia.
SR20DETs range from ~200 hp up to the current spec at 250 hp. That is unmodified
and you should easily be able to get 300 hp from the motors with some minor
mods. The FJs make less power (205 hp max in stock form) and are not a current
motor so parts are harder to find, but they are impressive motors too. I
recently tore one down while I was at Les' and I was impressed. You could easily
make an honest 250-300 hp from one of these (and still get great reliability).
The FJ will work with any B box trans as long as the NapZ front housing is used,
so you can get a great gear range by using one of the 81-83 280ZX (non turbo) 5
speeds combined with a NapZ front housing. The gear spacing on these trannys is
very nice and would work well with a 4 cyl motor in the 150-250 hp range with a
rear end of 4.11 or lower. I will be using this exact combo in my 510, an FJ20
(turbo eventually but maybe not at first) w/late 280ZX trans and an R190 LSD
4.44:1 rear end. Why the FJ and not the SR? Well, up-front cost, ease of fitment
in the Dime, and availability. Though a proper rebuild on the FJ will kick the
cost up much closer to the SR than I had planed on.
If you are going to go for the Nissan V6, I say go for the newer VQ series. Saw
one of these blocks at Nissan a few weeks ago and this looks like a great little
V6, with lots of potential. The 3.5 liter option with the VQ is a bonus too.
But I think a V6 or V8 may just be too much for the Roadster chassis and
certainly for the brakes. I think a smarter approach would be a 4 cyl that makes
less torque and revs higher. You can gear it to take advantage of this and you
won't be bending frames and eating rear ends. Normally I would take just the
opposite approach, but the Roadster chassis has limits and cost will become a
major factor if you have to swap to a different rear end, make major mods to the
frame, etc. But no matter what, I think a brake upgrade is a must.
One last idea, you could ask Les about the *U24* powered Fairlady he saw in
Japan back in November. :-) He said that made the 150 hp Solex 2 liter he was in
look anemic.
--
Marc Sayer
82 280ZXT
71 FJ510
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