GT2871 USERS. SR motor

[idahotuner]

and i read that the 52 trim was the best

[s15specR]

I think cody's running the 56t version, he had great results

[GabeS14]

Originally Posted by idahotuner

ok i gota question. when are you guys hitting full boost in 1st gear. because my boost seems delayed. seems like it starts spooling really quik but then full boost doesnt hit in 1st gear until like 4500 then the pull to 7500 takes like a split second. full boost for me right now is 16 psi. using my avc-r which i have boosting very solid. i have no spikes at all.

this is kinda delayed, but mine is exactly the same way, takes a while to reach full boost..then from 4500 to 7k is a split second.

[DrifterProdigy85]

56 Trim will make more power than the 52 trim. Cody made 400whp with his setup. Ive made about 420+whp with my 56 trim .86 A/R. I dont have dynoes to show but my trap speeds in the 1/4 were anywhere from 121mph on 21psi and 125mph on 24-25psi.

[anyotherone]

I made 386whp at 20psi on 93oct pump gas with the following setup:

Stock S13 Redtop SR
JWT S1 cams / valvesprings
Greddy intake manifold
Full Race turbo manifold (bottom mount)
3" downpipe/exhaust (no cats)
Enthalpy ECU tune
740cc Injectors
GT2871r .86ar turbine, 52 trim compressor, internal wastegate (t25)

I switched to the .86ar after starting with the .64 and not being satisfied.

I personally think that anyone using the 56 trim, with maybe some 272dur cams and maybe 7500rpms could make 450whp on pump.



Later I cranked the boost to 22psi and made around 420whp, but I don't have that dyno graph unfortunately.

[OBEEWON]

Dont buy BC 272's, and dont buy them for a .64. BC 272's are out of wack.

[brian m]

Originally Posted by OBEEWON

Dont buy BC 272's, and dont buy them for a .64. BC 272's are out of wack.

Just curious what you meant by that. I was planning on buying some

[fromxtor]

^^ Brian you want the 264s for the .64

[GabeS14]

Originally Posted by OBEEWON

Dont buy BC 272's, and dont buy them for a .64. BC 272's are out of wack.

Originally Posted by fromxtor

^^ Brian you want the 264s for the .64

Originally Posted by brian m

Just curious what you meant by that. I was planning on buying some

Me too so what you are saying is that the 272 arent efficient with the .64 turbo?
when you say outta wack? you mean runs funny or just inneficient?

[idahotuner]

what he means is the 272s come in to play as the turbo exits its efficiency rang. the 264 match up alot better to the gt2871

[OBEEWON]

Yes but more specifically, If you buy Brian Crower 272's you will be tunning forever but still be running like crap till you buy cam gears because they are 13 deg off center. BC isnt very helpful either, well no one is when you tell them they freaked up.

[idahotuner]

true i forgot about that little peice of information.

[GabeS14]

Originally Posted by idahotuner

what he means is the 272s come in to play as the turbo exits its efficiency rang. the 264 match up alot better to the gt2871

Ahh I see thanks...

Originally Posted by OBEEWON

Yes but more specifically, If you buy Brian Crower 272's you will be tunning forever but still be running like crap till you buy cam gears because they are 13 deg off center. BC isnt very helpful either, well no one is when you tell them they freaked up.

So what cams do you reccommend?
JWT
HKS
Tomei

[Jordan-S13-Silvia]

Originally Posted by OBEEWON

Yes but more specifically, If you buy Brian Crower 272's you will be tunning forever but still be running like crap till you buy cam gears because they are 13 deg off center. BC isnt very helpful either, well no one is when you tell them they freaked up.

Dude what are you talking about thats not true.

[idahotuner]

get some 264 cams. i have BC they work great.

[GabeS14]

Originally Posted by idahotuner

get some 264 cams. i have BC they work great.

no, I meant brand!

[OBEEWON]

Originally Posted by Jordan-S13-Silvia

Dude what are you talking about thats not true.

Would you like to put money on that? I went through 3 months of trouble shooting and tuning before I found out. I know 4 other people that had the same problem. Cam gears, or a new set of cams fixed all problems. Im sure not every batch was so, but the fact is some are, and a machine shop confirmed.

I have the BC 264's and they are fine.


Gabe
All those brands you mentioned are great. I would go with the JWT since they are more affordable and in the states if you have a problem.

[anyotherone]

When did you install your BC 272's? There was a batch of cams that were not ground correctly. I know because I had some issues getting mine tuned out on my first setup. I spent 8hrs on the dyno trying to get them dialed in with cam gears and a powerFC and they still did not build power like they should. I reinstalled them twice to make sure that I didn't botch it too before I had them checked out by a local professional that does cam regrinds and the like.

I finally ended up calling and spoke to Brian himself, he was very helpful - the key is to not get emotional and start throwing accusations around. Parts manufacturers have to deal with a lot of idiots that install the product wrong and blame the manufacturer.

I ended up going with the tried and true JWT S1's because I felt that they would match the powerband of the GT2871 .64ar that I was swapping in.

However, to be perfectly honest, JWT has worse customer service than BC in my experience - at least when something does not work as advertised.

[codyace]

Originally Posted by Z33dori

any one running a set up like this:
GT2871R .64 A/R
272 cams

i'm planning on doing this and i was curios to see how the power band plays out.

Your cams are not well suited for that little turbo. Get 260-264 duraation cams.

JWT S3 specifically.

No need to change anything in the valvetrain, just plop them in, and enjoy them. You can find them cheap used on sr20forum.com, from the sentra guys.

Originally Posted by umsports

You need to do it in 4th because of the 1:1 ratio.

And look at the correction factor on his run, 1.07/1.08...if you take that out, it's a 385 whp car.

Originally Posted by idahotuner

and i read that the 52 trim was the best

Compressor map it's nice if you're not running a big boost (like if you're running 12-17/18), but it seems that (at least to me) that you'll gain more from the better breathing from the tradtional 3" inlet, you'll gain more top end to match th ehigher 18+ psi boost.

Originally Posted by s15specR

I think cody's running the 56t version, he had great results

You betcha! Been running strong for nearly 3 years now. Like I said on Nico, I dynoed it last year on a bad night, with extra octane (which will hurt power, but I wanted to crank it 25 psi and be safe), the gears (4.60's, which will hurt peak power) and at 19 psi (because the internal gate sucks) and it made 395 on the lowest correction factor...so give or take 10 whp from last year with 20, the 4.08s and 93.....I think that's pretty good to say that the power remains the same.

I can't wait to get back on the dyno soon with my one piece driveshaft, crank scraper/windage tray/external gate

Originally Posted by anyotherone

I made 386whp at 20psi on 93oct pump gas with the following setup:

JWT S1 cams / valvesprings

I personally think that anyone using the 56 trim, with maybe some 272dur cams and maybe 7500rpms could make 450whp on pump.

I agree, but S1 cams? Is this on a KA? JWT doesn't make S1 for SR20.

Originally Posted by Gabe╚╗14

Ahh I see thanks...
So what cams do you reccommend?
JWT
HKS
Tomei

JWT or HKS. I personally support JWT because you can use all stock valvetrain components (saving you money and time in the end) and make the best power.

And for the last time, Brian Cower cams are JANK IMO. The 264's less jank than the bigger cams, but I wouldn't trust their stuff in my valvetrain.

Originally Posted by anyotherone

However, to be perfectly honest, JWT has worse customer service than BC in my experience - at least when something does not work as advertised.

I will say, that JWT doesn't ahve the best customer service, but you gotta think that they only have 4-5 workers there at any given time...Jim, Clark, Ben, the girl that answers the phone, and a shipper. It's not some huge company.

[Oneoverwrx]

we are running the 56trim and the .86 exh housing and trapping 123-125 on 17 psi. We are also running the bc 264 cams. I wouldnt do any bigger cams on this turbo setup. It does awesome and has 10 sec capablilities. I am positive we will run in the 10s next time out. We actually had to add some weight to the rear of the car and are now working on getting it to leave straight.

[codyace]

Originally Posted by Oneoverwrx

we are running the 56trim and the .86 exh housing and trapping 123-125 on 17 psi. We are also running the bc 264 cams. I wouldnt do any bigger cams on this turbo setup. It does awesome and has 10 sec capablilities. I am positive we will run in the 10s next time out. We actually had to add some weight to the rear of the car and are now working on getting it to leave straight.

What for managment, octane, and weight?

I'd love to get a race gas tune, jack the timing, and see what my jalopy makes.

[idahotuner]

i still dont believe this correction factor. sides i did my dyno in 3rd gear. i will do them in 4th next time. and see waht we come up with and make a comparison.

[codyace]

Originally Posted by idahotuner

i still dont believe this correction factor. sides i did my dyno in 3rd gear. i will do them in 4th next time. and see waht we come up with and make a comparison.

There is no reason not to believe it. Do some more reading about how dyno's work, and you'll see what I mean. Why do you think every dyno on the planet reads differently (Paging Steve K). For you to clearly not accept the 1.08 correction factor, is beyond me.

I'm not trying to 'hate' or anything, just trying to help you understand how it all works. Remember when I showed you how high/low even my numbers could be with just a simple correction factor change? Maybe I should claim 420/340 instead? Heck if we were on a Dyno Dynamics, we'd both be makign 350 whp haha.

[OBEEWON]

Quarter mile is the best measure of power. Trap speed, 60ft, 1/8, ET.

[s13envy]

i think trap speed is the only real measurement of actual HP. provided you aren't spinning all the way down the track.


and as for the BC cams, yes they do need cam gears and they NEED to be timed or atleast checked I know of 3 sets that were from 11-18degress off. when i had them in my car with stock cam gears, my car only made 90psi of compression. a couple buddies of mine were only making around 80psi of compression. they put in some cam gears and fixed the problem though.

[codyace]

Originally Posted by s13envy

i think trap speed is the only real measurement of actual HP. provided you aren't spinning all the way down the track.

The spin issue is killer for me. I was running 18 psi, and trapped 118 in a full weight, every option s14. It spun outa the hole bad, and after getting into 2nd, it gripped, and then ripped the tires off again. I didn't evne bother running 20psi.

I just wish I could take my coilvers/sways/re set my alignment for not track spec, and see what she does with slicks some day haha.

Originally Posted by s13envy

and as for the BC cams, yes they do need cam gears and they NEED to be timed or atleast checked I know of 3 sets that were from 11-18degress off. when i had them in my car with stock cam gears, my car only made 90psi of compression. a couple buddies of mine were only making around 80psi of compression. they put in some cam gears and fixed the problem though.

This is why I keep telling people with BC cams to be a bit skeptical of their machining and quality. Again, to me, I'd rather stick my JWT stuff in, not hafta change anything, and make good power. Screw the gears, springs, and dyno time....

[anyotherone]

Originally Posted by codyace

I agree, but S1 cams? Is this on a KA? JWT doesn't make S1 for SR20.



JWT or HKS. I personally support JWT because you can use all stock valvetrain components (saving you money and time in the end) and make the best power.

And for the last time, Brian Cower cams are JANK IMO. The 264's less jank than the bigger cams, but I wouldn't trust their stuff in my valvetrain.

I will say, that JWT doesn't ahve the best customer service, but you gotta think that they only have 4-5 workers there at any given time...Jim, Clark, Ben, the girl that answers the phone, and a shipper. It's not some huge company.

Haha... I meant S3 cams, sorry about that.

And you are correct, it's harder to keep a high level of support with a small company. To my knowledge, BC only has a few people working in that particular division though (manufacturing comes from the parent company)

I agree with you though about the cams being off. I've been working with them for over a year on development of cams for a certain japanese V8... lets just say I'm not impressed and leave it at that.

R&D for an engine is a straight forward problem, there isn't any excuse for the quality issues they have fairly consistantly laid forward.


On another note - the idea that power can be derived straight from trap speeds is pretty redicules... track times are way too dependant on variables, just as much as dyno numbers, imho.

[usdm180sx]

Originally Posted by codyace

The spin issue is killer for me. I was running 18 psi, and trapped 118 in a full weight, every option s14. It spun outa the hole bad, and after getting into 2nd, it gripped, and then ripped the tires off again. I didn't evne bother running 20psi.

I just wish I could take my coilvers/sways/re set my alignment for not track spec, and see what she does with slicks some day haha.



This is why I keep telling people with BC cams to be a bit skeptical of their machining and quality. Again, to me, I'd rather stick my JWT stuff in, not hafta change anything, and make good power. Screw the gears, springs, and dyno time....

So are you running stock valvetrain with the jwt s3 cams?

[anyotherone]

Originally Posted by usdm180sx

So are you running stock valvetrain with the jwt s3 cams?

I'm not trying to flame codyace, however I disagree about using aftermarket cams and stock valvesprings - especially with boost levels approaching or above 20psi. They are not difficult to install when the cams are out and the cost is minimal to avoid potential issues.

[idahotuner]

and i would have to agree. about needing new valve springs asa safety percaution