Basic mods + tune for 200kws, simple help
Posted 15 October 2017 - 11:23 PM
I'm looking to achieve around 200kws with my 200sx s15 for simple street cruising and a bit of fun no track days.
To achieve this I have this mod list
Front mount intercooler
3" turbo back exhaust (punched out cat)
Turbosmart boost gauge
Turbosmart boost tee
255lph walbro fuel pump
(Stock 6 speed)
I have yet to buy the injectors and flash because I'm not sure exactly how to go about tuning, do I need a dyno tune or simply that ecu flash tune...or both ? Do I need anything more or different ? The main concern is how I go about tuning, I live around Sydney so any tuners in Sydney that can be recommended would be appreciated.
Posted 16 October 2017 - 08:49 AM
Front mount intercooler: Pipe diameter doesn't really need to be any bigger than the throttle body, which is 2.25" iirc. Get something that fits, but isn't massive, and be creative with your routing if you're going for an FMIC. Avoid drilling holes at all costs, as it's technically a defect, and if you're only going for 200kw there's no need to hurt your resale value.
3" turbo back exhaust (punched out cat): Buy a cat man, c'mon. A 3" high-cell metal cat will lose you a couple of kw at best, the cost is nothing compared to the EPA fine if you're ever caught with a punched cat, and they genuinely help the environment. Ceramic cats break, but metal ones last plenty long. Having a punched cat as for testing during a tune is fine, but it's a bit of a dick move to run one on the street.
Turbosmart boost gauge and Turbosmart boost tee: This was a great idea in 1998, but these days, not so much. If your goal is response, you want an electronic boost controller. The reasoning for this is that you want the wastegate flap to stay shut right up until you hit your boost target, then have it pop open, rather than have the flap slowly open as boost climbs. FYI you can achieve the same result as a boost tee by shoving a metal rod with a hole drilled in it in the vacuum hose leading to the wastegate, so why spend the $50 on a fancy restrictor? After all, the T28/T28BB is pretty much limited to 12psi.
Personally, I'd opt for a high-end EBC that can double as your boost gauge, so you only need to install a single unit. I did a bunch of research and eventually bought one of these, albeit I still haven't installed it. Build quality is great, and reportedly they perform well and are easy to use. Not cheap, but ya gotta pay to play!
255lph walbro fuel pump: This or a Bosche are fine. Just be careful you don't buy a counterfeit unit, as that was (and probably still is) an issue back in the day.
555cc injectors: I'd personally go for 740cc Nismos to give yourself some headroom, especially if you swap turbo later, but 555s should be completely fine iirc. Not sure if 740s would suit E85 at 200kw, but they might, and a flex tune may appeal to you. Price shouldn't be too dissimilar.
Nistune: Yep, this is the way to go. I hear a lot of good things about Johnny on here (I'll eventually get him to tune my car), on NS and SAU he's "Dose Pipe Sutututu", but you can probably reach him through his website http://www.trak-life.com/. Not sure if he still tunes as a hobby or not, but he might be willing to help you out. Johnny is in Sydney. Can't comment about other tuners, as for every one guy saying how great a tuning shop is, there's another saying that the same shop is shit. Really seems to be more a case of "ask for xyz guy at xyz shop", rather than "xyz shop is great".
MAF: The oem S15 MAF maxes out at around 200kw, so you might want to consider a Z32 MAF. If you wire the plug as a piggyback to the oem harness, you'll always have the option to easily roll it back to stock.
Intake pipe: Consider whipping up a metal intake to avoid the rubber one sucking closed.
Bov: If using the oem recirculation valve, do the screw mod to avoid it bleeding air. Google it for more info. The stock bov can hold boost nicely if the bleed hole is plugged.
Cams: To hit 200kw on an S15 engine you'll likely need cams, otherwise expect around 180kw on 98 octane if using the stock cams. Personally, I'd think 180kw is fine for the goal of "fun street car", and getting caught up with numbers is a mistake.
Exhaust manifold: The oem manifold can handle more than 200kw, so leave it if you want response.
Dump pipe: 3" dump will help more than most of the system, so if you're running a stock dump consider upgrading. If not, then it's whatever. I recommend the Tomei fine-cast 3" bellmouth dumps, but they're expensive, and with a little filing and a lot of swearing, the chinese shit can be made to work alright. Fitment sucks, but that's how it is if you go cheap.
Edited to say Z32 MAF. Nice pickup Mr Rocket
Posted 16 October 2017 - 09:31 AM
Posted 16 October 2017 - 04:43 PM
No the stock s15 T28BB runs brilliantly on 17psi in my experience. That is the sweet spot for this turbo. 12 psi is way too low.
I'd definitely go 740s. Brand new they are the same price. Can't say for second hand.
I think you mean a z32 here.
No you don't need cams to hit 200rwkw with a s15 stock turbo on an s15. Cams with the stock turbo will actually yield a poor result. You need a bigger turbo to take advantage of them imo.
Everything else I agree with.
The only point you missed is induction. Depend on what state you live definitely hook up a pod filter (QLD) or in stricter states like Victoria cut the bottom out of your on air filter box with an angle grinder and buy a high flow panel filter for it such as K&N (very lightly oiled). Did this with my old S15 and it looks completely stock from the top and yielded about 15 extra rwkw (tested on the day) I remember it well.
Do all this with your s15 and you will hit 190rwkw - 200rwkw.
A very fun street car. But you will get sick of it quick lol. I know I did. Good news is you already have all the mods so buying a bigger turbo is easy. Then you just need a retune.
Posted 16 October 2017 - 07:06 PM
PM me for prices if you're interested.
Posted 17 October 2017 - 08:30 AM
Interesting. I've heard of people running higher boost than 12psi on stock T25/T28 turbos back in the day, but iirc they pumped too much heat much beyond 12psi to make it worthwhile, and I've always understood ~18psi to be around the failure point of the T28 turbo. If you're running E85 I can see you getting away with higher boost in colder weather than Sydney, but otherwise my initial inclination is to think that you might have a highflowed turbo lol.
I could of course be completely wrong, and ideas have changed with people pushing the envelope, I just can't see 17psi on 98 octane being a viable standard due to all the results people have had in the past. Irrespective, it all comes down to the numbers when tuning anyway, as you'll boost it up whatever seems safe, and that's all you get.
Yeah, I've now edited that to avoid confusion. Nice pickup!
I'm just going off the numbers folks got in the past chasing 200kw with a T28. Power is a peak value after all, so the overall drive with cams might be poor as you said, but iirc cams were the lynch pin in hitting that 200kw peak for a lot of guys, especially those with tired SR20s that probably were a little down in compression.
We're on the same page though; keep the stock cams and just have fun with it.
Good point, I had indeed forgotten about that one. I'd personally just opt for a hole in the box and leave it at that, as the results of 'panel vs paper' and 'panel vs pod' tend to be so similar, however paper is a lot more effective with regard to filtration. You can always test it on the dyno easily enough anyway, by removing the paper filter and doing another pass.
Posted 17 October 2017 - 05:59 PM
Btw I just got my 180sx tuned today and I hit 196rwkw on 16psi with all the said mods above.
Very happy with the result
Check out details in the turbo reference guide if you are interested.
Edited by s15rocket, 17 October 2017 - 06:10 PM.
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