Ok so after seeing how laggy my friends gt25/40 on his fully built sohc is, its making me think that i might need some nitrous to help spool my turbo.. i have a gt30r,
Turbine
-Wheel: 60mm w/ 84 trim
-Housing: .82 ar
Compressor
-Wheel: 76.2mm w/ 56 trim
-Housing: .60 ar

and his specs on his gt25/40 is

-Wheel: 53mm w/ 62 trim
-Housing: .86 ar

Compressor
-Wheel: 60mm w/ 60 trim
-Housing: .70 ar

I have bigger wheels obviously.. so right now my motor is 84.5mm bore 89mm stroke, 8.9:1 c/r maybe still finallizing the c/r with the machine shop.. gsr head p/p valvetrain.. also have the lovefab manifold blah blah.. 750cc injectors.. As far as cams go i can either stick with the stock gsr's or if i put out about $500 i can get the new comp turbo vtec cams..

So getting back to my point. He didnt hit full boost til about 6k extremely laggy but yes i have a bigger displacement than him. How safe and how big of a shot could i run to help spool the turbo up to get out of the hole. I was thinking of a 50 shot wet. I'm using hondata as a method of tuning.

 

anyone?

 

Don't run nitrous, you won't need it. I'm running a GSR Motor/ITR trans, with an SC61-S housing on an 8.5:1 .5mm over gsr block. 18 pounds of boost by 5000 RPM's, and it comes up in a flash out of the hole anyways. I don't drop out of boost at all when I shift to second. With a larger motor and a smaller ball bearing turbo you're going to have no trouble spooling it. Not only that, but if you throw in nitrous you're just going to overpower the tires and spin like hell anyways.

 

My friend was running a dx tranny with longer gear ratios and my other friend with the same setup as him used an si tranny and made 330... but when he swapped out to the dx tranny he made the same power as my other friend 270... I am using a ls tranny so the gear ratios are going to be longer and its going to feel like forever to spool... your tranny had a close gear ratio which does help spool... correct me if im wrong... im always trying to learn...

 

Yes this is true, the LS gears arn't as good for acceleration and it will take longer to get into your powerband, but I still don't think you're going to need nitrous. I think that GT30R is going to take to, at most, around 4000 RPM's to spool. General consensus is that you don't way to spray nitrous any lower than 3000 otherwise you're asking for a backfire. 3000 RPM's in first gear in an LS is 15 MPH. 4000 RPM's in first gear in an LS is 20. Think of how quickly 15 MPH comes up even with a naturally aspirated stock LS motor or a lightly modded NA LS motor. Pretty damn fast. If you spray a 50 shot at 3000 RPM's that's immediately going to add nearly 100 ft-lbs of torque, which is going to seriously overpower the tires and cause you to spin big time. Assuming an 8500 shift point and 23" tall tires, after you shift out of first gear with an LS trans your revs will NEVER be low enough that you will fall out of boost. Heck, even for me starting to make boost at about 3800 ramping up to full boost at 5000 in first gear I am seeing boost and scrambling for traction before I hit 20. Even set as low as 10 psi in first gear it spins azenis like they're jelly as soon as boost starts to come on, so I only think nitrous would magnify the traction issues we face with a FWD chassis.

Also, keep in mind i'm running a 680-700 HP capable turbo that is non ball bearing. You are running a 500 HP capable ball bearing turbo. My turbo has a 61mm inducer, yours has a 58mm inducer. You arn't going to have any trouble spooling that sans nitrous. Lag becomes a bit of a good thing when you're driving on not-so-sticky street tires.

 

True I see where you are coming from. Being that i have to run a cable tranny, 92 rs integra, and gsr and b16 cable tranny's are a rare find i will have to stick with the ys1 for now. I was looking for something to help me into my powerband faster and i wanted to hit full boost by at least 5k if not sooner. My friend doesnt hit full boost til 6k. I have the azenis' but as sticky as they may be i'm pretty sure you break traction extremely fast. BTW how much power are you making and what is your setup motorwise. What kind of cam's are you using? Like i previously stated i've read numerous stories about gsr cams putting people well over into the 500 range.. But would you think the new comp turbo cams would be worth it? My machinist showed me a dyno with the comps and gsr's and the comps made 25 hp and 25 tq over the gsr's but the only problem i saw with that is that it did not give in detail what the setup was motor and turbowise. But 25 on both sides is still very impressive.

 

One of the reasons your friend didn't hit full boost till so late is becase he's running a .86 housing on such a small motor, and if it's that laggy I would bet that his motor is running very rich, producing low EGT's which compound the lag problem. You have a 400+ CC advantage over him, and a marginally larger turbo. If I'm hitting full boost at 5000 with a significantly bigger turbo that is non-ball bearing, and 200CC's less displacement, there is no reason your turbo shouldn't make full boost at around 4000, 4500 TOPS.

My setup is a stock sleeve GSR, .5mm over 9:1 JE's, eagle rods, stock head with portflow springs/retainers, ITR cams, victorX intake, Lovefab SST, PTE SC61 S-housing with .63 A/R exhaust, PTE 750HP intercooler, 3" dp to apexi n1, ITR trans, and hondata.

 

I told him to get a smaller turbine housing to reduce lag. Yes my turbo is marginally larger than his and i can see your point now. I think he's at 1.7 if i can remember correctly.. so i got about 300cc plus or minus some. Thanks for your help Chip... much appreciated..

 

back from the dead.. just an update on my friends turbo.. we found the problem... silicon hose... he put a 2.5" on a 2.25" and it was leaking thru there... this turbo spools from beginning to end and pulls hard all the way on his sohc.. the gt25/40.. being that it was a saturday and it would have been a bitch to find a place and atp was closed i had a 2.5" hump hose and a 2.25" straight from my old turbo set up.. i just cut about 1/3 of the 2/25" and super glued it into one side of the hump so it would cover that part of the ic and then to the 2.5" piping.. im very impressed with that turbo...