Waterguy

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> 240 RWHP / 280 RWTQ
For now anyways.............
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Well, darn it, somebody had 255/290, and it wasn't me! I posted my <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=18;t=005113#000000" target="_blank">charts</a> earlier; sure would be nice if some of the other guys/gals would post theirs and not make my rely on my memory.

Who owned that Silberossa 951S?

Jason_86_951

Wasn't it Eric?
I think he was also the one who has 255/290.

Jim H.

Well, I like the response on this thread. It's good to hear about everybody else's numbers and plans. Danno is going to burn me another set of chips and hopefully I'll get them installed before my track day. (Note to Danno - Great product and service, I hope your business really takes off if hasn't already)

Regarding what boost I'm running? I'm just running off the stock boost gauge so I'm thinking I'm running 15psi max with the factory preset reliaboost. It is pegged at 2bar until around 5k rpm at which time it starts to fall into the 1.8 bar range by redline. It appears to be boosting as it should be, but then again I'm just starting to learn about 951s.

Question for those interested...How do you think I can flatten out the torque curve? It peaks nice but seems to fall off too rapidly. In the car it feels like it too. It really accelerates better in 4th gear at high ways speeds (3500 - 4500 rpm) verses 3rd gear (which feels a little anemic at 4500 - 5500 rpms). I was thinking that I might upgrade the turbo and go with a stand alone system this winter but still on the fence. Gonna have to talk Alan C. into helping me tune it first.

BTW - First ever dyno run. The car sounded so great under full load. The B&B catless exhaust and carbon silencer were intoxicating. I feel very lucky to be starting my porsche habit with this car.

Jim

Waterguy

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> Regarding what boost I'm running? I'm just running off the stock boost gauge so I'm thinking I'm running 15psi max with the factory preset reliaboost. It is pegged at 2bar until around 5k rpm at which time it starts to fall into the 1.8 bar range by redline. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">The fall-off in torque at higher rpm is typical of the flow characteristics of the kkk26-8 turbo. You already have improved breathing and exhaust, about the only things left are better intercooler and MAP/MAF. The way to really improve it would be a different turbo that flows better at high rpm.

The peak torque is limited by engine displacement, efficiency and boost pressure. A 2.5 L 951 will typically peak at about 290-300 ft-lbs at 15 psi. You gain about 10 ft-lbs per psi boost, so it looks like you are running about 19-20 psi; this is also why your torque curve starts dropping so much as the rpm goes up; the kkk 26-8 turbo just can't maintain this boost level. The stock gauges are notoriously inaccurate, and once you pin them at 2 bar, you could be running anything.

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> 3rd gear (which feels a little anemic at 4500 - 5500 rpms) </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Only by comparison. I wish I had your problems. <img border="0" title="" alt="[Eek!]" src="eek.gif" />

If you want to flatten your torque curve by raising the top part, I think you should be looking at replacement turbo/standalone, as you suggested.

Jim H.

Okay learning lots here. thanks. But...

I understand your logic that I might be running 19-20 psi. I guess if that is true then my reliaboost must not have been set to the 15psi like I thought it was. OR are there more complicated issues at work here.

Looks like I need a good boost gauge as my next upgrade.

Jim

tazman

Once you get your boost gauge if you can get your boost to stay at 15psi to 6000rpm that will help a little with the dropping torque curve. If you get rid of the cycling valve and just run the reliaboost and a decent factory shimmed waste gate you should be able to hold 15psi to above 6000rpm with no problem. With your high torque numbers I would bet you are boosting way more than 15psi.

Jake951

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Jim H.:
<strong>I understand your logic that I might be running 19-20 psi. I guess if that is true then my reliaboost must not have been set to the 15psi like I thought it was. OR are there more complicated issues at work here.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Jim,

Are your injectors stock? If they are, my guess is you're running less than 19-20 psi because otherwise the stock injectors would be maxed out and you would be much leaner. When I first installed my Reliaboost, I was seeing 17-18 psi and running way too lean with stock injectors. The stock gauge in the dash read 2 bar. Not surprisingly, it did not run well until I readjusted the Reliaboost back to 15 psi.

Jim H.

Stock injectors with stock fqs setting (0) as well. Without an adequate boost gauge I figured I'd use the A/F ratio to let me know if I could safely handle whatever boost was being delivered. I also figured that if the A/F ratio was good then the boost was likely 15ish given the stock injector capacity. Seems like good logic but I must admit, when I saw the numbers I was both happy and puzzled (seemed too good).

Anybody else want to weigh in on the validity of an A/F ratio as a surrogate for maximum boost?

This thread turned into something other than the initial idle problem and the title kind of hints that there is a problem with Danno's chips. I'm changing the title a little...

Jim

Jake951

If all goes well, I'll have some dyno numbers next week for my '89 Turbo with GURU MAP Stage 1. Except for the GURU kit, the car is 100% stock and I'm running 15 psi. By the seat of the pants, it's very strong and very fast--certainly much stronger than it was with Authority chips.

Jim H.

Well I talked things over with Danno. He believes that my numbers are going to be typical numbers for 951 "S"s at 15 PSI of boost. I really don't want to over boost my car so I feel less concerned about the strong TQ and HP numbers at this point. We also discussed that my car is running great on the original chips so we're going to leave well enough alone. A boost gauge is in the works. I'll update people as to the boost level the car is actually running at as soon as it is installed.

John (Jake) Can't wait to see your dyno numbers. If Danno is right we should be close in HP and TQ. Please keep me in the loop.

Jim

Waterguy

I look forward to John's dyno numbers as well. It would be nice to think these numbers will be typical for a 951S at 15 psi, but I doubt it. Your boost gauge numbers and John's dyno numbers should settle it, however.

As far as not having enough fuel, the stock injectors should be fine with these mid-range torque/hp numbers. They run out of capacity if the high boost is carried to high rpms. I agree with your assessment that if the A/F ratios are good, you probably aren't endangering your car. I still think you must have high boost levels, and should get that boost gauge sooner rather than later.