T25 loses it's umph at top end.

[Foxcolt]

Well I was fookin around with this prelude last night on the way home. We stoped at a light and raced (eat me). Took em by a considerable amount.

Then he followed me on the highway. At around 75 we gunned it in third. Noticed that from 6 grand to 7 I wasn't pulling on him anymore. After I shifted to fourth I pulled.

I've always known that t25's aren't the best turbo's in the world but I didn't know they lost their steam that early in the RPM band. Kinda surprising.

However it might just be in my case as my SR only makes around 220 at 14psi. Not the 250 that everyone claims. I haven't really put forth much effort to find out why my SR makes so low of power since I'll work out the kinks when I put on the 2540 in the spring.

Just thought I'd share.
Jed

[nrcooled]

If you take a look at any of the spec sheets the max power made in a stock SR is at 6 grand (205hp @ 6000rpm) &nbsp;I won't shift after 6500rpm because....well there's no more power. &nbsp;I am also running 12psi and w/ the cold she has been pulling very hard but my slipping clutch keeps telling me that she's pulling too hard <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'> &nbsp;

PS 'ludes are soooo fun to beat up on (turbo tegs are fun too)

[Steeles]

yeah I was kinda suprised when I took mine to the dyno power was that soon. i still take it to 7 just for staying in the powerband sake but other than that yeah its pretty much done

[Foxcolt]

Just seemed weird that with a grand left to go on the tach the power fell off so quick. I was really surprised. damn the t25!!!

Jed
Did you decide on a clutch yet?

[nrcooled]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Did you decide on a clutch yet?
</td></tr></table><span id='postcolor'>

Yeah, &nbsp;I going for the Star SpecII just don't have the cash for it now and even if I get it now I need help getting it in. &nbsp;I am going to try to recruit John into giving me a hand dropping the tranny. &nbsp;Maybe you could help?? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>

[drifting240sx]

if you were in the phoenix area i would help out. i have experiance in changing clutches in a sr. and i tell you its a bitch to put in. maybe it was all the bad luck i had??? but its still a bitch to put on.

good luck &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

[Foxcolt]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (nrcooled @ Dec. 09 2002,12:42)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Did you decide on a clutch yet?
</td></tr></table><span id='postcolor'>

Yeah, I going for the Star SpecII just don't have the cash for it now and even if I get it now I need help getting it in. I am going to try to recruit John into giving me a hand dropping the tranny. Maybe you could help?? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'></td></tr></table><span id='postcolor'>
No prob. I'll help out. Your gonna be faced with 2 options though.

1, buy a lightend flywheel

2, Car will be outa commission till you resurface the flywheel.

Jed
I love the smell of gear oil in the morning <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/laugh.gif" border="0" valign="absmiddle" alt=':laugh:'>

[nrcooled]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Foxcolt @ Dec. 09 2002,1:48)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (nrcooled @ Dec. 09 2002,12:42)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Did you decide on a clutch yet?
</td></tr></table><span id='postcolor'>

Yeah, I going for the Star SpecII just don't have the cash for it now and even if I get it now I need help getting it in. I am going to try to recruit John into giving me a hand dropping the tranny. Maybe you could help?? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'></td></tr></table><span id='postcolor'>
No prob. I'll help out. Your gonna be faced with 2 options though.

1, buy a lightend flywheel

2, Car will be outa commission till you resurface the flywheel.

Jed
I love the smell of gear oil in the morning <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/laugh.gif" border="0" valign="absmiddle" alt=':laugh:'></td></tr></table><span id='postcolor'>
That is exactly the reason why I haven't gotten the clutch yet I just want to get them both at the same time and I really want the JUN/TODA flywheel. I just need to get the cash together

Edit: I also love the smell of gear oil....I always thought I was the only one <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

[Foxcolt]

Fidanza started making flywheels for the SR. Cheaper than Jun/Toda.

Now back to topic: ME!

Jed

[nrcooled]

Oh yeah almost forgot. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'> &nbsp; HKS cams and a bigger turbo (which you are getting) &nbsp;Will remedy that problem. &nbsp;Then my friend you will be pulling very hard to redline. &nbsp;I am trying to keep the power to a minimum due to the track use. &nbsp;Not really a big drag racing freak. &nbsp;I would love to get a ride in yours after the turbo goes in though.

[Foxcolt]

I'm not really to in to drag either. I just want a car that'll get me chicks.

I hope to have the turbo on by the spring - summer. I'm really interested to see what it'll do. I've heard so many conflicting stories I went from wanting to sell the turbo to wanting to put it on just to see what the heck all the fuss is about <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/laugh.gif" border="0" valign="absmiddle" alt=':laugh:'>

I'm gonna hold off on the cams. at some point in the next year I'm gonna build a good head. Rocker arm stoppers, port polish, valve springs, cams blah blah etc etc.

What's wierd is that the t28 doesn't lose power like the t25. It'll pull all the way to redline and more if you want it to. I've come to realize that the t28 isn't an upgrade of the t25. It's a whole new turbo/design altogether. Performance wise.

Jed

[Steeles]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Foxcolt @ Dec. 09 2002,12:54)</td></tr><tr><td id="QUOTE">Fidanza started making flywheels for the SR. Cheaper than Jun/Toda.

Now back to topic: ME!

Jed</td></tr></table><span id='postcolor'>
the fidanza is what im running in mine with the Spec Stage II great combo &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

[uiuc240]

Well, Jed, I'm guessing we could start to draw a T25 compressor map. &nbsp;You're probably getting into the lower efficiency range, and you're feeling the boost drop off. &nbsp;It's really no surprise. &nbsp;Just look at the Turbonetics maps for a small T3 or any of the small Garrett turbos and you'll see what's happening. &nbsp;

I'm quite interested to see what'll happen with that 2540. &nbsp;Some Z32 owner said that he switched from twin 2530s to 2540s and he gained NO power, but they lagged more because of the mismatched nature of that turbo. &nbsp;Who knows?

Eric

[Foxcolt]

Yeah I hear horror stories like that too. But for every bad story I hear I get a good one. Like a guy in the UK running close to 370 on the 2540.(don't know about lag). Or the HKS tech at nopi who told me that the turbo w/ cams will net me close to 400hp with spool up starting at 3 grand.

Edit: OR in some UK ricer mag, there's a guy with a 200sx (s13, ca18det) running a 2540 claiming over 350 bhp.

Bottom line is I need to stick that sucker on and find out for myself. Worse comes to worse I can sell it and buy a 2835.

Jed
who's turbo microwave is blowing up all his food(seriously). Maybe I should take the turbo off it and put it somewhere else? That way I won't have to clean the whole microwave out everytime I cook mac & cheese. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/laugh.gif" border="0" valign="absmiddle" alt=':laugh:'>

[uiuc240]

Yeah, like I said before, I'm sure it's not a BAD turbo. &nbsp;Shit, it's gonna make TONS more power than you have now. &nbsp;So naturally it's going to feel sweet. &nbsp;However, I think just by reading about how turbos are sized and engineered, it makes sense that this will have strange spool-up and boost characteristics. &nbsp;But, without trying something else (like a 2835, 2530, or T3/T04, or something) you'll never really know. &nbsp;I'm sure it will be just awesome and you'll have a superfast car. &nbsp;I'm just looking forward to having about 250 at the wheels with stock ECU/MAF/injectors by just plopping a T28BB in there and a boost controller (12 psi anyone??)

Eric

[Foxcolt]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (uiuc240 @ Dec. 09 2002,2:39)</td></tr><tr><td id="QUOTE">Yeah, like I said before, I'm sure it's not a BAD turbo. Shit, it's gonna make TONS more power than you have now. So naturally it's going to feel sweet. However, I think just by reading about how turbos are sized and engineered, it makes sense that this will have strange spool-up and boost characteristics. But, without trying something else (like a 2835, 2530, or T3/T04, or something) you'll never really know. I'm sure it will be just awesome and you'll have a superfast car. I'm just looking forward to having about 250 at the wheels with stock ECU/MAF/injectors by just plopping a T28BB in there and a boost controller (12 psi anyone??)

Eric</td></tr></table><span id='postcolor'>
Good point, I haven't tried any other turbo. I have however seen some of them in action (3037 - t3/t04b) so I'll have some reference point.

Regardless, if that turbo doesn't get me somewhat close to the 400hp mark i'm gonna ditch it and go for the 2835.

Speaking of that. Eric can you do all that math mumbo jumbo stuff and find out if 550cc's are good to 400hp?

Edit: From what I've seen that t28 can get more than 250 at the wheels. And can flow close to 18psi or more without falling short like the t25 does at anymore than 14.

[uiuc240]

I know the T28 can push more than enough air for 250hp. &nbsp;That's just my ballpark number. &nbsp;The injectors and MAFS get maxed out at about 270, so I figure at 250 I should be in a decently safe area. &nbsp;I'm not going for max power...that will happen when I have enough money for a full buildup. &nbsp;I just want a little more scoot.

Injector sizing:
http://www.rceng.com/formula-1.gif

Resultant HP:
http://www.rceng.com/formula-2.gif

RC Engineering page...sweet (http://www.rceng.com/technical.htm)

So this is what you get

550cc/min/10.5 = 52.38 lb/hr

52.38*.85 (we'll use 85% duty cycle) = 44.523 lb/hr

44.523/.55 (BSFC = .55 with decent tuning) = 80.95 hp for one cylinder

80.95*4 = 323.8 hp (at rated static fuel pressure)

Not enough for your 400 hp goal. &nbsp;You need 740s bro.

Strange thing, however...I reran these numbers for 370s, and I get a max hp of 217...which is way lower than the 270hp we know they are capable of (been tested by others).

If I replace the duty cycle with 100%, I get 256 hp....and if I leave the BSFC at .5, I get 281 hp.

Interesting. &nbsp;I'm not sure what to trust now. &nbsp;Ideas, gentlemen?<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

Eric

[uiuc240]

The calculators at the bottom of that page say that I need 550's just to see 300hp AT THE CRANK with 4 injectors, a BSFC of .6 and a duty cycle of 85%. &nbsp;Seems fishy to me. &nbsp;I want to know why we're running these margins of safety and whatnot.

Hmmmm &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/mad.gif" border="0" valign="absmiddle" alt=':angry:'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hmmm.gif" border="0" valign="absmiddle" alt=':hmmm:'>

Eric

[Foxcolt]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (uiuc240 @ Dec. 09 2002,3:21)</td></tr><tr><td id="QUOTE">The calculators at the bottom of that page say that I need 550's just to see 300hp AT THE CRANK with 4 injectors, a BSFC of .6 and a duty cycle of 85%. Seems fishy to me. I want to know why we're running these margins of safety and whatnot.

Hmmmm <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/mad.gif" border="0" valign="absmiddle" alt=':angry:'> <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'> <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hmmm.gif" border="0" valign="absmiddle" alt=':hmmm:'>

Eric</td></tr></table><span id='postcolor'>
That's weird. I knew that 550's were gonna run close to my goal. As I've seen 550's run close to 400hp on other cars.

Either way. Those calculations do seem off. i'll do a little research tommorrow and see what I can dig up

Jed

[FSPtwo4d]

The 550cc injectors are good to about 350hp on pump gas and 400hp on race gas. &nbsp;Above that you will need 740's or bigger. &nbsp;

Late

[uiuc240]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (FSPtwo4d @ Dec. 10 2002,12:36)</td></tr><tr><td id="QUOTE">The 550cc injectors are good to about 350hp on pump gas and 400hp on race gas. Above that you will need 740's or bigger.

Late</td></tr></table><span id='postcolor'>
Well, that's what we've heard too...do you have any way of proving this, though? &nbsp;I'm going on tried-and-true math calculations here. &nbsp;They are saying NO. &nbsp;Give me a good reason to believe what you're telling me.

Eric