Views on best engine spec for my project?

[Ewen]

Hi,

I've spent a good bit of time digging through the information in this (excellent) site, and have picked up lots of good info. However, I'm wondering if folk might have any views on the specific project I'm looking at. Sometimes it's difficult to decide on 'the one best solution' when reading across various articles and posts. Here's what I'm up to:

I'm transplanting an early LS400 1uz-fe into an S13 Nissan 180SX (suspension, brakes etc will be properly sorted for the new set up). I'd like about 400 - 450 flywheel HP allied to equivalent levels of useable torque.
I've never been a fan of turbod power delivery, preferring the linear / precisely controllable delivery of a supercharged or traditionally tuned N/A set up. Thus, I'm keen to go down either of those routes.

An easy way I'd reckoned of getting there would be to use an Eaton M112 supercharger. I had thought I'd need to rebuild the engine with a lower CR, but from what I read this might not be necessary if targetting 'only' 400 - 450 HP. If I can get away with the stock CR then that'd be handy.
However, being new to the 1uz I was wondering if there's a view on the best set up to deliver 400 - 450 reliable, street-driven HP?

Would an Eaton M90 be too small or highly stressed? If I use an M112 will I need to lower the CR? What about injector sizing? What are the stock ones good for? Will the stock AFM handle the increased flow rates etc? If not, is there a commonly switched-to unit? I reckon I'll probably need an aftermarket ECU, and if using a supercharger probably won't need cams / head work.

Then again, if I target, say, 350 - 400HP instead can I get away with the stock ECU / injectors / CR etc more readily? I'd happily settle for a bit less output if it means significantly less time and expense in engine prep.

Also, briefly, transmission-wise, I had thought a Supra R154 5 speed manual would be the way to go (as per advice here), however, I'm also toying with an RB25 Skyline unit as the R154 shifter is seemingly placed quite a bit too far forward when transplanted into the Nissan S13 shell.

I've read that the Toyota W58 manual trans comes with a variety of shifter linkage lengths. This might be handy for shifter placement, but I wonder if there's a view on the suitability of this lesser spec unit as compared to the R154?

Views much appreciated.
Thanks,
Ewen

 

[Anaema]

if you did do head and cam work, you might be able to get away with using a M90. the same boost level with more airflow will yield more HP.

450bhp might be pushing the stock pistons and rods a bit too much.

 

[bango]

There's a member here JustinGT8 running around with 400+rwkw...unupened motor(stock internals) so 400-450 seems to be ok with a good tune...though he's running turbos, you can get similar with SC..looking for 10-12 psi from M112 might get u there..unopen..

 

[Zuffen]

Ewen,

I'd be inclined to try and run a twin screw supercharger as an Eaton (or any roots type) heats the inlet air and causes detonation which then means you need to dial back your timing.

My choice would be don't open the engine and use a Richwood twin screw set up with decent headers.

You'll need an aftermarket ECU to run it. The group buy on the Adaptronic ended last week but I will be seeing if we can get more at the GP price. I'm after one for another member.

You will need to go up to bigger injectors.

I'd also run water/meth injection.

 

[Ewen]

Hi,

Thanks for all this input guys.

Anaema - Had thought about some cams and head work, only the 1UZ tuning 'scene' over here in the UK is way behind Oz / NZ. If I can get similar results with a stock engine and M112, then I'd probably go that way then the M90 and head work if for no other reason than it'd be much cheaper.

Bango - I've seen the vids of JustinGT8's Celica (I think). If that's running 400+rwrk (more than 500 rw HP) on stock internals then that's good news - it's a lot more than I'm planning. I reckon I'd be something like, what 350 rw HP -> ~ 260rwkw?

Rod - I'd seen the Richwood inlet manifold and had planned to use one of those, ideally along with their 'semi kit'. I'd not considered the Richwood supercharger as Eaton M112s are reasonably easily obtained (and are thus relatively cheap) here in the UK what with their being used on supercharged V8 Jags. It's also quite a neat unit externally and I'm keen to avoid altering the bonnet line. However, nothing's set in stone. Price allowing, I'll take a look at the Richwood unit. I was aware of the Eaton heating issue, and if the Richwood runs significantly cooler, then that would be a plus. I guess it's swings and roundabouts - more pricey supercharger v no engine rebuild and no intercooler.

A group buy on the ECU would be good. I'm not at the stage of doing that just yet though - I'm currently assembling what's needed in stages, rather than being flush enough to just buy it all in a oner - Working on that though, so fingers crossed...

Water / meth injection - it's not something I know a great deal about in practical terms, truth be told. If I were to go with water injection, for example, would I need a continual injection whenever the engine's running, or would I just need it if really going for it?

Bigger injectors - any views on sizing?

As an aside, gearboxwise, I'm beginning to come round to the idea of a Nissan Skyline / Z32 box as I think there'd be less fab work and alteration needed for this conversion.

Thanks again,
Ewen

 

[Anaema]

some water/meth injections make use of boost dependant controllers. they turn on at a certain boost level, say 10 PSI. with a turbo this might not be such a problem, but with a roots or a screw SC, you might be in boost for longer periods than you would with a turbo. so you might run out of water at an inopprotune time.

i have never heard of a heat dependant meth injection controller. i think that would be much more useful than a controller centering around boost pressure.

 

[Zuffen]

I have a Snow stage II water/meth system and I can dial in swich pressure and flow so I can tailor the w/m to the engine's needs.

The temp rise comes from the compressing the air so temp or boost dependant will give the same result.