Engine options, opinions please

[Andy]

Hi All,

The importer reckons the S15 will be arriving in the first week of August so I really need to decide what to do engine wise.

My options are keep the na block and source a turbo head or source a complete turbo engine. It is staying SR20 but which one? At the moment I'd prefer a redtop out of a 180sx as I'm not keen on nvcs/vvt and besides I plan to uprate the cams anyway.
I'd like to get around 420bhp out of it once I'm done so I'd also like to know which bits of the engine break or melt at that power so I can uprate them too.

 

[garys15]

bin the na it wont make 420 without a loooota work...
stick with a red top sr, for 420 you will need rocker arm stoppers definately and your on the extreem side of the limit for the bottom end so if you want it to last id get it fully fordged.. also maybe a little bit of head work
your looking at £4000 for a fully fordged red top tho so not cheap

 

[DeanS15]

may as well get a blacktop vvt engine, you can still fit any aftermarket cams and an exhaust sprocket just retaining the vvt sprocket on the inlet side. you will be able to get that 420 no problem once the engine has been forged and if using a suitably specc'd turbo - transmission wont like it at all though. losing the vvt affects the driveability so i understand, and most people are against it. hope this is of use....

 

[LuPix_S15]

I'd say have a word with Jez @ Horsham Developments...


He's a top man and very knowledgable on SR tuning

 

[Andy]

Thanks for the replies guys, for making that power I'm planning on doing this http://www.tomei-p.co.jp/_2003web-catalogue/e130_NEO_turbo.html and getting the bits Tomei don't make but you still need like fmic, uprated clutch etc. I know on that it says the turbo is only good for 400 but I've seen it rated to 420 elsewhere?

I think this could take some time to put together (while I save up for all the parts) but hopefully it will be worth it eventually. I'm leaning towards just getting a complete turbo engine now, either way it would have to come apart for a forged bottom end it looks like.

 

[garys15]

for over 400bhp you need a fairly extreem clutch mate, something like a exedy twin plate.. £1100 and at over 400 you will be doing gearboxes quite alot if your drib=ving it hard so may want to look into a z32 or rb25 conversion box

 

[DeanS15]

if you're just looking for big horsepower with the bigger turbo and not worried about having no boost lower down the rev range then the garrett 2871r .86 should make on or near that power.....you may want to put your feelers out on the sxoc where there are a few people running that turbo, even the .64 version will make up to 400 at a push - its been done before but constantly wringing that out of that turbo wouldnt be great for longevity i'd of thought. you can even run up to 400bhp on the stock bottom end from what i've read...the weakest links are headgasket and transmission, if you are going to be running it on the limit (those turbos make thier power way up there) then people also opt for solid lifters to avoid rocker arm breakages which could be costly should it happen...

 

[Andy]

Thanks for all the advice guys, you are all giving me a lot to think about.