Garrett GT25R vs. T3/T04E

[VitaminT]

Sweet.

Make sure you have some new manifold gaskets and be prepared to fabricate/modify your hotpipe and inlet pipe.

That should be about it to get it up and running.

If you don't have cams you may want to start thinking about them.

[VitaminT]

Oh and as long as you get side feed injectors you can use the stock fuel rail. Secret Service let me to believe it would do fine even with 740cc injectors.

[Dori Dori]

Why 740's? Little extreme don't you think?

[VitaminT]

That is what I was planning on with a .86A/R so I can't say.

[240SXer]

740s are high, but why not go a bit over? i'm gonna be running .86 A/R. I plan on 400whp. 550s might be running close to max.

[AussieS15]

Hi Guys,I've some how stumbled across your forum.I'm from Australia and currently own a 2002 200SX S15 Spec R Silvia which is fitted with the GT25R turbo plus a heap of supporting mods.Your posts have been interesting as I went through the same questions when I had to choose a turbo.

[VitaminT]

Very nice. Would you mind posting more info on your setup.

[Dori Dori]

740s are high, but why not go a bit over? i'm gonna be running .86 A/R. I plan on 400whp. 550s might be running close to max.

Because it's not needed, your idle may suffer, and you'll get worse gas mileage.

[Nathan]

Because it's not needed, your idle may suffer, and you'll get worse gas mileage.

Is that really a concern for someone who want's 400whp? I know I have similar goals and I gave up on good gas mileage long ago...it'll still be better than my blazer was! As for idle, 72#'s idle decently, I dont see why 740's wont be even better. Overkill rocks

[240SXer]

How much power can 555's support?

I do daily drive my car so how much would the gas mileage suffer with 740s vs. 555s? Right now I usually get about 22 (highway / street combined), then anywhere from 14-19 if it's pure street, and 24-26 if it's pure highway. That's good enough for me. I assume when I get the electric fans and recirculate my bov i'll do better by 2-3mpg on the highway.

So, gas mileage is an issue, but i'm not going to let it stop me. If I can get better without lacking power that's cool. But it seems that for my goals 555s might not be enough. I plan on running like 10psi on the street then whatever I need to win whatever car i'm against (street race a lot). I assume 14-18psi on pump gas?

There is a fully build Supercharged 91 Mustang out here who keeps smoking me. He runs 12.2 on street tires. I need to be able to take him. He lives by me so we line up fairly often. With my Nittos I was on him till about 25 when he walked away It's embarassing.

[msaskin]

How much power can 555's support?

Going by the standard formulas at RC engineerings website:Assuming a .65 bsfc (fairly conservative), and an 85% injector duty cycle, 555cc injectors should be good for ~550 crank horsepower.

That said, I'm aiming for 350ish rwhp myself and will probably be running 550s.

~matt

[Movingviolation240]

Scott (the guy who's opinion I trust more than my own mother's) says that it's not really safe past 360rwhp. I've seen people make 400rwhp on them, but once again it's not exactly safe. You have to remember you only want to run an injector up to like 80% duty cycle, anything past that and your asking too much of it.

Paul

[f150intally]

Yes listen to Paul and Scott for that matter. Do not use 550s if you ever have more ambitious goals! YOu will regret it in the end because you will end up spending more money.

Plus 350-400 is kind of scary on 550s. Limit around mid 300s (reliability goes down after that because of high duty cycles).

[msaskin]

f150 & movingviolation,

I agree with you both totally. I may end up with 740's (or equivalent lbs/hr) depending on how things go. Most injectors (while rated at 80% DC) tend to run best between 80-90% duty cycle. Also you can run into some tricky problems by forcing yourself to run at overly low (<60%) duty cycles.

The rule I've always followed is to run the smallest injectors possible to get the power levels you want at ~85%DC.

~matt

[Jala47]

Scott (the guy who's opinion I trust more than my own mother's) says that it's not really safe past 360rwhp. I've seen people make 400rwhp on them, but once again it's not exactly safe. You have to remember you only want to run an injector up to like 80% duty cycle, anything past that and your asking too much of it.

Paul

What isn't safe past 360rwhp?? 555cc injectors?

and while we're talking about HP what's the most anyone has seen a 240 handle, i'm just curious most i've seen was 5xx on an S13 Red top

[Movingviolation240]

Because it's not safe, you run out of fuel. You don't want to run past like 80% duty cycle, and that's at about 360 rwhp.

[240SXer]

I plan on usually running low boost 10psi or so on the GT25R. Also, for a short while i'm going to be running my T25 with the program. Is that going to be an issue? T25 w/740cc injectors. I know the 550s won't be enough for what I want. It will be 95% of the time, but that 5% is what's not gonna work.

[VitaminT]

I think the only person that can help you on whether the ecu flash will "work" with the T25 is Secret Services. It may run and drive, but just be pittifull until you upgrade the turbo. I would make a phone call.

[240SXer]

They said it would be fine. I was just curious what ya'll thought

[VitaminT]

Just a suggestion, but if downtime is so critical have you though about buying a second SR ecu, having SS flash it, and then doing everything at once. Then you sell the non flashed ecu in the end.

[240SXer]

I'll do that if the Tuned ECU is an issue. I see what you're saying though, but everyone tells me there won't be a problem. If it is that's what i'll do.

[Dori Dori]

Well, I never said to use 5xx's...doesn't anyone make a 6xx side feed? If not, I guess you're SOL and have to use 740's

[msaskin]

Or you can just go to top feed for the same price (or cheaper).

Side Feed - $450-$550Top feed rail - $150Top feed injectors - $250-300 MAX for 4.

~matt

[VitaminT]

I like the idea of topfeed, but then you have to buy the connectors/pigtails and some resistors (if needed). The sidefeeds he will get a plug and play AND this is probably the last set of injectors he will ever buy.

[msaskin]

True, but clips + resistor packs are under $30.

This is why I'm glad I'm going with a haltech; can drive low impedence OR high impedence injectors, and the flying-lead harness comes with MSD style injector clips!

~matt

[240SXer]

Secret services does not have a program for those.

[VitaminT]

That is good to know. I am probably going to get the SS tune in the near future.

[240SXer]

They have 550s and 740s though.

[AussieS15]

Thanks VitaminT...here's a list mate.

Year/Make/Model:2001 Nissan S15 200SX Spec R(First Reg. Dec 2001)

Engine Hardware:Nissan SR20DET 1998cc DOHC 16 Valve 4 cylinder

Engine Accessories:Garrett GT25R 400HP Ball Bearing TurboGarrett 0.9bar Wastegate ActuatorAVO Tuned Length Stainless Steel Exhaust ManifoldTuned Std ECU with Daughter BoardHKS EVC-IV Boost ControllerHKS Super Sequential BOVHKS Super Fire Iridium PlugsHKS Hi-Power 3.5-inch ExhaustHKS Step 1 Cams 256in/264ex 10.5 liftHKS Adjustable Cam Gear ExhaustSR20DE 63mm Throttle BodyNismo 555cc InjectorsNismo 4.1L/hr fuel pumpCusco Oil Catch CanGenie Custom Twin Dump Pipe from TurboHigh Flow 3-inch Cat ConverterBlitz SUS-power C1 Air FilterApexi GT spec SRS intercoolerXspeed Custom intercooler pipingXspeed Custom 4-inch inlet pipe to turboCustom Cold Air DuctingNissan 300ZX Z32 80mm Air Flow MeterFSE Adjustable Fuel Pressure RegulatorBraided oil lines for turboHigh pressure silicon coolant hoses for turboSilicon vancum Hoses throughout

Driveline Hardware:Nissan 6 speedNissan R34 GT-R Helical DiffBrass Button Clutch1 ton pressure plate (standard pedal feel)

Brakes and Suspension:Endless PadsHKS Super Form SpringsKoni Adjustable ShocksWhiteline Swaybars front and rear powder coated yellow with linksFulcrum Camber correction kit x 2Cusco ALU Carbon OS type strut bar front

Bodywork:Nissan Spec R body kitNismo clear indicator lenses

Rolling Stock:DTM Blitz style dark chrome 18x7.5-inch front and 18x8.5-inch rearFalken GRB FK-451 tyres 225/40/18 frontBridgestone RE540S 245/40/18 rear

Interior Gadgetry:Blitz Dual Turbo TimerHKS EVC Boost Control DisplayGreddy Electronic Warning Boost MeterJDM Pillar mount boost gauge holder

Stereo Components:Rockford Fosgate RFX 8350 head-unitAudio Control Overdrive line driverAudio Control EQX-Series II2 x Rockford Fosgate Punch 60x2 (running mono)1 x Rockford Fosgate Punch 40i1 x Rockford Fosgate Power 250x2Lightning Audio capacitorHSU Research 12-inch DVC SubwooferDynaudio 7-inch splitsAudioart & Technologies Custom RCA leadsOdyssey 800 batteryAll panels lined with Dynamat

Some older pics here:http://www.xspeed.com.au/ssport/20s15/20s15.htm

[240SXer]

Wow. Pretty sweet. How are those 550cc injectors doing for ya? Which GT25R ar do you have? .86? How high have you boosted it?