Bretts dynoplot

[Rboosted717]

After reviewing the plots, I think OJ did a good job with them. The Air/fuel ratio needs to be cleaned up, yet that can only be done with a controller. I bet if he tuned the air/fuel ratio to a solid 12 or so, the trq will jump up to almost 150, and the who will raise more in the mids range. Anyway, nice setup! If this decive with a stock JRSC can hit these numbers over and over, that will be awesome!
Good job JR!

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Mike Marsey
'98 ITR #0717
Supercharged w/218whp @ 5.5psi
For all your JRSC type R questions, go to:
http://www.geocities.com/superchargedtyper/

[Batoutahell]

As I understand it, the "innovation" behind these 2 cars is that JR lowered the tip-in fuel pressure down to 45-50psi in order to lean out the fuel across the board. However, based on these dyno's, it seems that it pays off not to lean out the bottom end too much. Is an adjustable fuel pressure riser the answer? It's starting to look like the typeR kit should be sold without the walbro fp, and instead include a cartech fmu.

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'00ITR#739
JRSC, JR Walbro FP, JR intake, J&S SafeGuard, JR BTC, v-afc

[rjaffey]

Hmm,

What's that "TPS" comment on run number 10 refering to?

[Rboosted717]

The TPS comment is refering to the unit JR made thats like your TPS mod. they call it the "black box." Look at the other type R posts here and Mr.Detail explains it more.

------------------
Mike Marsey
'98 ITR #0717
Supercharged w/218whp @ 5.5psi
For all your JRSC type R questions, go to:
http://www.geocities.com/superchargedtyper/

[brettd]

Thanks Mike!

[zip]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Rboosted717:
The TPS comment is refering to the unit JR made thats like your TPS mod. they call it the "black box." Look at the other type R posts here and Mr.Detail explains it more.
<HR></BLOCKQUOTE>

Why would you need the TPS mod when conducting WOT runs?

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Mods

[Batoutahell]

Actually, I'm kind of surprised that JR calls it a "TPS" modification. That's definitely Rafe's trick, but JR claims that their black box is different than Rafe's trick in that it is triggered by boost (map sensor), not by throttle position. Hmmm.

[rjaffey]

JR's mod is different. It tricks the ECU into thinking the MAP sensor is seeing less vacuum at lower RPMs and part throttle. The problem is the MAP sensor seeing high vacuum even when there's boost in the manifold under these condtions. The ECU supplies too much timing and not enough fuel thinking the air density is much lower than it really is. JR's solution was to crank the baseline fuel pressure way up to compensate, but the rise rate of their regulator is too steep and causes a/f to go way rich as MAP sensor starts seeing less vacuum.

Both mods address the same problem, but differently. The JR mod allows the a/f ratio to stay leaner under light, part throttle boost with closed loop control, while the TPS mod says as soon as there's boost in the manifold, the ECU should consider the engine under full load and run exclusively off of maps. It doesn't go too rich at this point as the MAP sensor's still seeing high vaccuum, but lowering baseline fuel pressure is critical to make this true. Otherwise gas mileage takes a dump.

I was just wondering what the "TPS" comment meant. If it means that one car has the TPS mod and the other has the MAP sensor black box, then I'm having trouble understanding the a/f plots. First of all I assume both runs are at WOT. Therefore neither mod should make a difference on the dyno. They just allow the baseline pressure to be lowered a bunch, thereby preventing the a/f ratio from going too rich up high and killing the power. Without either mod, the tip in and part throttle performance would suffer badly, but the WOT dynos should be unaffected.

[Rboosted717]

Brett just E-mailed me his dynoplots to be posted. So here is it:
" It shows a later run of my car and Travis' car. You can see where OJ brought the fuel in earlier in Travis' car by the AFR at the bottom of the page."-Brett



------------------
Mike Marsey
'98 ITR #0717
Supercharged w/218whp @ 5.5psi
For all your JRSC type R questions, go to:
http://www.geocities.com/superchargedtyper/

[mr detail]

I have an email into OJ to see what it means. I think he is out of the office today so I hope to have a reply tomorrow.