why with a SC.....

[RStoR]

I'm a SC newbie guys...so please go easy!


I own an ITR and had my first ride in a SC ITR tonight. The car is rough tuned and makes about 200whp. The blower whine was cool, but over-all I wasn't "blown" away by it.

I had an aggressive NA set-up until recently and made 190/130 on OE compression. The set-up was sold because of issues I had with the idle and timing belt tension. This is what got me thinking about a blower.

In doing some research, it seems that many SC ITRs are running the same high 13's that my NA set-up ran, while at 5.5 psi. Why is this? One would think that the blower would have a serious tq advantage over the NA set-up. Can anyone help shed a bit more light on this for me? Thanks.

[Turismo]

I think it's all in the tuning. 200WHP sounds low for a JRSC ITR compared to some I've seen around here. I know someone here's making mid 260's WHP and FLAT TQ on a JR ITR setup and some add on's, which would be a considerable difference compared to your friends.

I know the ITR's have some tuning issues that seem to be problems, but solutions have been found for the most part.

<font color="#a62a2a" size="1">[ March 01, 2002 11:00 PM: Message edited by: Turismo ]</font>

[2kbill]

Chris,

I think your concerns are legit, based on what I've seen posted by the R drivers here. It seems that the added compression and bigger cams work counter to getting the most out of the stock JR blower. While there are a few that have done well with their blown R's, there have been a number that have scrapped their JR setup due to dissatisfaction or chronic problems.

I'm sure you will carefully study the situation before making your move. My only advice would be to use a standalone like Hondata with the R, which would allow you to address the tuning issues which keep the kit from reaching its potential.

Disclaimer - I don't own an R, so this is all based on secondhand information.

Bill

[nexusone]

Where's Mike? He'll give you the rundown in the SC-ITR situation.

[RStoR]

Thanks for the replies guys!

Yes, I know about the success that Mike has had, but he is one of the few. In fact, I seem to recall somewhere that Mike even said he may have chosen another route if he had it to do all over again.

I've always had a liking for blowers. I like what they do and how they do it "for my needs." The key is, will one make me happy with my current car! The ITR does seem real finicky, but changing out the OE ECU seems to be a proven winner just as Bill stated.

Here is a quick list of wha I figure I want/need to make good power. Give me your opinions please?

JRSC 5.5 pulley (progressing to 8-9 lb)
Hondata Stage 2 w/Boost/Datalogging (P72 ECU)
Hondata intake mani gasket
Comptech airbox
RC 440 injectors
AEM FPR
Kamikaze ITR header
2.5" CarSound cat
2.5" custom exhaust

Do you think I need a J&S or will the Hondata be enough? Do you think I'll benefit from a 3" exhaust? I'll run a test-pipe at the track.

<font color="#a62a2a" size="1">[ March 02, 2002 11:22 PM: Message edited by: RStoR ]</font>

[vactor]

c'mon guys. i think we all realize that blowers are NOT meant for 1/4 mile times or BIG hp numbers. they ARE meant for ultra responsive acceleration. don't use a blower if your goals are low et's. don't use a trbo if u want super quick throttle response. decide what you want first, and don't rag on the setup if you chose the wrong one for what you want. my $.02 ...

[RStoR]

vactor~

I think your taking my point in the wrong way. My ultimate point isn't to compare NA vs SC ITR 1/4 miles. I only use this as a reference to answer my ultimate question; why aren't SC ITRs killing NA ITRs?

Since I don't live near any SC ITRs making "great" power, I only have dyno plots and 1/4 mi. times to help evaluate this. In talking with several owners, it seems that a mid-high 13 is realistic for a SC ITR making 200-220 whp. This is usually in street form with full interior. This doesn't take driver skill into acct. On the other hand, I know of a lot of NA ITRs making 190-195 whp that run mid-high 13's. Most of these guys have removed the rear seats; ie. 25-30 lbs max. It just seems that if the blowers are making 10-30 whp and 15-30 ft/lbs than the NA set-ups across the powerband that they should be killing them. Do you not agree?

In looking at these dyno plots, it seems that a SC moves the peak tq down the rpm range compared to a NA set-up. Most seem to peak wround mid-5000 vs mid-6000 in NA form. Just as with a shorter final drive, this should increase the acceleration at of the SC car at lower rpms. In reviewing several testimonies about FDs, it seems that the longer gearing pulls back in the top of the powerband. Could this be the case with the SC? The NA car peaks later, so it closes the gap. I'm just speculating here. I was hoping some of you guys more educated/experienced with blowers could help me understand.

Hopefully you understand that I'm not looking for peak numbers or the lowest e.t. now. In fact, I very rarely even drag race. I reality, I do 4-5 track schools a year so reliability after 20+ minutes of flat out driving is what I'm more concerned with.


In looking at some dyno plots, it seems that a SC moves the peak tq down the rpm range compared to a NA set-up. Just as with a shorter final drive, this increases acceleration at lower rpms.

[RStoR]

Nice reply! Thanks for the advice and insight.

PS: I found an ITR owner in WI running an Endyn stepper pulley for 8.5 psi with a Hondata system pulling 258 whp/ 171 tq. Crazy!

[randomwalk101]

Chris,
if you are to go the SC route, you don't really need the J&S if you tune your Hondata right...J&S is a nice insurance but not needed in my opinion with Hondata. Most ITR owners have prob with their non-Hondata set up because the stock map dumps too much fuel at top end. You won't have this with Hondata.

[vactor]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif"><font size=2 face="Verdana, Helvetica, sans-serif"><font size=2 face="Verdana, Helvetica, sans-serif">Originally posted by RStoR:
vactor~

I think your taking my point in the wrong way. My ultimate point isn't to compare NA vs SC ITR 1/4 miles. I only use this as a reference to answer my ultimate question; why aren't SC ITRs killing NA ITRs?

no problem RS. i think i did get the point, but let me rephrase my take. i think part of what you hear is that there isn't a lot of info available that lets you compare NA and SC itrs right now.


Since I don't live near any SC ITRs making "great" power, I only have dyno plots and 1/4 mi. times to help evaluate this. In talking with several owners, it seems that a mid-high 13 is realistic for a SC ITR making 200-220 whp. This is usually in street form with full interior. This doesn't take driver skill into acct. On the other hand, I know of a lot of NA ITRs making 190-195 whp that run mid-high 13's. Most of these guys have removed the rear seats; ie. 25-30 lbs max. It just seems that if the blowers are making 10-30 whp and 15-30 ft/lbs than the NA set-ups across the powerband that they should be killing them. Do you not agree?

in general i agree. what you should look at is the trap speed. that will show you the amount of power made. as almost ALL SC 1.8 liter guys will tell you, launching at the strip on street tires is EXTREMELY difficult due to the tremendous tourque applied to the wheels in 1st gear. therefore they seem to be traction limited in getting off the line. but they will still have faster trap speeds than NA cars due to more power being made. BUT, put both cars on a road course or on an autox track or on the street, and the SC car will hand the NA car it's ass on a platter. (see SteveW (and a BASE 6 psi kit) and him killing a FULL Nick Wong MUGEN'D out ITR. (steveW, feel free to share the details)
i am sure that it is reasonably clear that 1/4 mile times re not indicative of street performnce or throttle response. it is a better indicator of ultimate power. that being said, it is my understanding that the SC and HIGLY tuned NA itrs run similar times, and can be show on the dyno to make similar power, although as you mentiond, the torque curves are different, and that the SC cars generally also make more torque.


In looking at these dyno plots, it seems that a SC moves the peak tq down the rpm range compared to a NA set-up. Most seem to peak wround mid-5000 vs mid-6000 in NA form. Just as with a shorter final drive, this should increase the acceleration at of the SC car at lower rpms.

see above re: traction problems. the SC car will have more ability (theoretically) to accelerate if all other things (such as gearing) are equal, at ny point where it produces more torque at the same RPM as the NA car. however, when gearing is changed, you can just calculate the actual applied torque at a specified rpm to see where which car should have better acceleration. this again does not take into account traction.


In reviewing several testimonies about FDs, it seems that the longer gearing pulls back in the top of the powerband. Could this be the case with the SC? The NA car peaks later, so it closes the gap. I'm just speculating here. I was hoping some of you guys more educated/experienced with blowers could help me understand.


you also need to look at the peak torque numbers as well as the area underneath the torque curve. if the area under the curve is greater for on car, again in theory, it should have greater acceleration as opposed to a peakier car that has less total area under the curve from the two delta rpm points used.


Hopefully you understand that I'm not looking for peak numbers or the lowest e.t. now. In fact, I very rarely even drag race. I reality, I do 4-5 track schools a year so reliability after 20+ minutes of flat out driving is what I'm more concerned with.

from the things i have seen and read, a well tuned base SC kit on an ITR will put a big ol' crap eating grin on your face in those applications >)
[qb]

[QB]</font></font></font></td></tr></table></td></tr></table></BLOCKQUOTE>

<font color="#a62a2a" size="1">[ March 03, 2002 12:33 PM: Message edited by: vactor ]</font>

<font color="#a62a2a" size="1">[ March 03, 2002 12:34 PM: Message edited by: vactor ]</font>