sidewaysil80

hahah i was set on a 2871r with hks step 1 cams UNTIL i saw your results djcobra and started researching the 28rs yesterday (was hoping you would chime in). the other thing is currently have the gt28r so i dunno if the 28rs is worth the upgrade.
DJCOBRA what rpm do you hit 15psi? i'm trying to compare lag lol. oh and as far as tuning i'll be going to a well known nissan guru and pioneer of sr swaps here on the east coast. he be og and an aem GENIUS.

and jspaeth, thanks i didn't realize that boost could be realized that low...i guess it's time to compare that to the 28rs. also, would a staggered cam setup such as the hks step 1's decrease lag time or is it not worth it and better to run a higher lift smaller duration such as the the tomie poncams

jspaeth

How is that an upgrade?

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sidewaysil80

i have the garret gt28r (s15 spec r turbo) and one of the options i'm thinking about upgrading to is a gt28rs .86 (disco potato)...what are you missing lol?

Psycho 240 Freak

How laggy was your set up? Which trim do you have? There are 3 different trims for the .64. 48, 52, and 56. From the experience with my 2871r set up and reading other people's set ups, depending on which trim you have you'll hit full boost in the late mid 3000's to very early 4000 rpm. Which imo isn't too laggy. For 330 whp, you'd have to be boosting above 17 psi with a 28rs anyways. A couple years back I was running a HKS GT2530 which is similar to the GT28rs .64. At 17 psi with stock cams, exhaust manifold and stock turbo elbow, I was only getting 280 whp on a Mustang Dyno. Hitting full boost around 3300-3400. I think with upgraded cams, exhaust manifold, turbo elbow, and upping the boost would've gotten me close to 330 whp, but that seems like too much work for this turbo. BTW, I ended blowing the HKS GT2530 turbo up by pushing 21 psi trying to get that magical 300 whp mark.

sidewaysil80

it was a gt2871r .64 but i think the lag was due to the un dialed in cams and the greddy intake manifold. in additon i belive it only made 320whp at 19psi which REALLY leads me to belive the cams were way off. i'm just really wary of giving up all the low end i'm used to with my 28r...i already have an ems and all the bolt ons imaginable so it really comes down to turbo choice.

EDIT:
have any gt2871r users tried a staggered valve setup AND a staggered cam setup to increase low end response and help it spool faster? or is that too much staggering lol, seriously though, could that have any adverse effects?

jspaeth

Honestly, almost no one with these size turbos touches the valves, as I believe the consensus is that it's not really worth it.

Staggered cams, yes....probably 256/264 or 264/272.

My apologies, I thought you were saying a disco potato was an upgrade from a 2871R

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sidewaysil80

hahaha no problem i was just confused. i'm coming from a 10psi gt28r that while drifting i can just hammer the throttle and it will break loose. i'm deathly afraid of losing that. thats why i keep toying with the gt28rs as a happy medium between the gt28r and the gt2871r. but i was thinking with a staggered cam/valve setup and a port and polish it would substainly increase response with the 2871r .64

codyace

Sounds like a crappy tune and cams are to blame for your car not makign the power and have the response you are lookign for. I'd honestly go with a .64 2871 (as it will spool equal a 28rs .86) and then you'll have the top end you want. However with that said, here is a car we recently dynod

Stock Engine, BC 264's, 7500 limit, light PnP, Greddy IM, GT28RS .86, Tubular Exhaust Manifold. Tuned at RT Tuning n PA. 18 or 19 psi IIRC



Makes some awesome power, but kinda light in torque.

Now compare that to my car for example (same dyno, similar conditions). JWT ECU, JWT S3 Cams, Greddy Manifold, 20 psi.




To me, even with the 1-2 psi difference, this is nearly a 60 ft lbs difference (not to mention the 40 hp difference)


Now here is another comparison for you, for sake of mind, and to show you what a difference cams would make

SR20DE (9.5:1 stock compression, so marginally better spool) Stock high port (similar to s14) manifold, Modified GTiR manifold with extrude hone and swain (similar to the factory RWD exhaust manifold), JWT ECU, JWT S3 cams, @ 17/18 psi (overlayed on my dyno)



Equal toque, but a severe difference in HP (and retention, that stock IM kills those cars). Regardless, the Sentra made similar HP to the other 240 I just posted (360 whp), but it too made almost 60 more ft lbs than that 240. Granted it lost top end power, but again the intake manifold is to blame.


So, like I said earlier, I'd opt for the 2871r in .64 turbine housing, and go from there. Also, let it be known that both my car, and the Sentra have stock heads, aside from the JWT S3 cams. I find it ironic that both our cars made a HUGE difference in torque compared to the BC ones.

I wouldn't even bother with staggering cams. JWT S3 or HKS 264 Step II's are the only way I'd go. JWT's are safe to 7850 on stock valvetrain, while HKS Step II's require springs.

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codyace

Get a final drive set if you're really worried. a 4.6 FD would be incredible. I may have another set for sale soon, I'll let yo uknow if you're interested.

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sidewaysil80

ok AWESOME, thanks coday i really appreciate it. i'll keep everyone updated.

djcobra

sidewaysil80: I hit full boost 15psi at around 3600rpm, peak torque at 3800-4000rpm and a huge smile on my face! Only down side of the GT28RS is lack of top end, thats where the GT2871r shine. However, for the Street and Mountain runs I like to stick to my DISCO! I'm an Alberta/BC guy, the mountains are only 45min drive away.

Steve.

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slider2828

^^ When in the mountains would you be in RPMs lower than 3800 or 4k RPM?

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codyace

Also take note of the difference in power per RPM as well. My car, and my friends car with the JWT S3 cams make 300 whp nearly 1000 rpm sooner.

It's nice to 'diesel' out of corners with the spud

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jspaeth

I don't do any drifting, but I know traction in 1st even in warm weather is near impossible.

Anything but warm weather, 2nd gear kind of spins.

3rd gear and lower, if you are at >4000 RPM and romp on the throttle, it fully spools VERY quickly.

I would imagine if you are doing drifing and are in 2nd or 3rd and want to break it loose, throttle or throttle plus a small amount of clutch kick should do the trick NO problem

But I don't care for drifting even though my car is essentially perfect for it lol

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Oneoverwrx

whats up guys. Just picked up an s14 zenki w/SR. Motor has apexi 1.8 hg, arp headstuds, BC 264 cams, BC springs and retainers. Car has a 2871 with .86 housing. Using an safc at this point with plans of a haltech or aem in the future. Car has sti injectors and a z32 maf.

Some of you all may remember me from this thread about 30 or so pages ago. Took a friends s13 to [email protected] with basically the same set up. At that time we were running out of fuel at 17psi. We thought it was running out of injector but the real problem was the fuel pump wiring. The fuel pump was not getting a good power source. So....now...

Running an s14 with this and hoping for similar times out of a few more psi. I have a meth kit on the way so that should help me out as far as fueling goes. Might try a few passes on 25psi with race gas and meth. Car is heavier though so it may not do as well as his s13 did but it will be fun.

2fast4y0u

^ if i can get near mid 11s with my setup it would poop my pants. my buddy in his evo woudl hate me for ever considering he spent $36k just to buy his car.

jspaeth

This is the same symptoms I am having. I am seeing duty cycles in the 90s, but my peak ouput is only like 360-370 whp on 740cc injectors with 3bar fuel pressure and a Walbro.

I think my Walbro must be crapping itself and unable to keep up under heavy load, bc when I look at my injector duties (in ms), they increase pretty linearly with load, and then all of a sudden they just start going up at a much faster rate.

Have a new Walbro waiting to go in, but I am concerned then that when I put it in, all of those heavy load portions of my map are gonna be rich as shit.

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roninwon

ok i finally got the car tuned yesterday, s13 redtop,cp pistions 87 8:1, eagel h beam rods, balanced crank, 1mm oversized ferrara valves, 3 angle polish, hks 272 cams with cam gears, RAS, titanium springs, tomei expreme manifold, gt2871r 86., 740cc tomei, fpr tomei, greddy intake manifold, apexi intake, apexi PFC, and a greddy profec b2

so i had the car tuned for 91 for obvious reasons and at only 14.9 pounds I got 339whp and 260wtq
thinking about doing a meth injection in order to raise the boost but until then im happy

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xpertsnowcarver

^^^Here's your last dyno run and results.



I believe its on a Dynojet 248.

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S13 curtis

lol you can run higher than 15psi with 91 octane and 8:1 compression ratio not to mention a PFC with 740cc injectors.

by looking at the dyno graph looks like you will make more power if you rev it out higher as it looks like you making good power up top but whats up with those torque numbers? it will look good with a decent 22lbs of boost and extend the rev limit. im not trying to be an ass but i would be pissed with those numbers, but then again you were only on 15psi.

roninwon

Exactly I could run higher numbers with higher boost but I wanted to keep it safe since i'm dd it. When I do the water meth kit the. I'll up the boost but for now I'm good. Steve even showed me other pulls with the same set up and I was higher than most

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2fast4y0u

well i have no bragging rights yet because i havent dynod my car, but...15lbs of boost is nothing, and i have similar setup just bigger injectors and .64 ar and im running 19psi a boost.
i have never seen anyone dyno a car like that either. why didnt he just go easy in the low gears then max it out up top?

Oneoverwrx

jspaeth- check your wiring to your fuelpump. Do a rewire to the alternator and you will boost your output on your walbro. If i start having problems with this car i am going to rewire it to the alternator.

740s will take you into...if not past 500whp. Hell...subaru guys make 500 on 740s.

Im looking to be in the 425+whp range on my 550s and meth. I will say this...i have never used meth on a car that is only tuned using an safc but i hope i can line it out enough to work.

roninwon

im not sure man cause i really have no idea on how to tune but he did tell me that his dynojet reads lower numbers so i could be pushing a little more

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codyace

Um, who runs that dyno as that is the completly WRONG way to dyno a car. No need to bang through the gears like that for a simply HP pull (or even tuning), holy crap is that dumb and unsafe.

Also, why not cross the rear straps in the back...yeesh!

...all you need to do is get it into Get it into 4th (or 3rd for some lesser power cars with long gearing) and just roll into it. No need to drag race it...holy shit.

550's are way to small. Maybe spraying that @ 4 bar base, but even then way to small.

You should really get 72 lbers, or at least 615cc sidefeeds.

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roninwon

he did that for shits and giggles the way he tuned the car was in 3rd gear pulls that was just the last run

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codyace

ok just making sure. We've done '1-4 pulls' to see how it affected power band/peak and there was little to know difference. Then agian this was 3 years ago when we first used to fuck around with the dyno. I still will only go straight with straps on non moving wheels, seems to keep it very steady.

Speaking of which, we really need to get a fuckin diesel digital pickup...

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xpertsnowcarver

^^Right, the video was just the last pull to show the power band for each gear. We told Steve we were taking it to the track the next day, so he sampled 1-4. In regards to tuning, he tuned the PFC at various throttle positions in 3rd gear.

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Oneoverwrx

550s are plenty of fuel for 18psi and stock fuel pressure. Afrs are in the low 11s through the mid range and come up to about 11.8 near redline. Plenty of fuel. I would say no meth and 25psi on some 110 would be fine. Probably be in the low 12s for afr.


This is a proven set up, i thought i proved that a year ago.

I do have plans for bigger injectors and a real ems but i like to see what i can do with the simple stuff. Also...my main focus is my civic so until im done with it(mid summer i would assume) the 240 will not be getting anything new.

codyace

Log your duty cycle. 550's are not enough for 400 hp, this side of completely maxed out at 3 bar. If running 4 bar then you'll have enough. You can think all you want, I know what duty cycle 50lbers/550's/Sti/60lb/615cc run at at 18-22 psi @ 3 bar of fuel pressure as I've personally logged multiple setups with these different injectors on different tunes.

Also you can't say 'oh it works great look, 25 psi on 110' because I know for a fact your setup is maxed out with a 1:1 regulator then, and at point your injectors are simple just dumping fuel. Thankfully 110 is pretty hard to detonate, and at that level you're not really making a ton of power. Try doing that with some big power and you'll have an explosion. (not to mention now you're on the level of 5/16 OE lines being to small)

Running injectors at 100% duty cycle 'to prove a point' is nonsense to me. But if it works cool. I'll reference you to multiple guys who had injectors literally 'burn up' and cause failure

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