Dave07997S

Was this from the dealer as a CPO or was 3rd party? Porsche doesn't offer an extended warranty other than CPO here in Cali.. If you did please enlighten me, other wise I may not keep the car once the lease is up.

Sad to see you getting rid of the S, I read on 6speed that you were considering a GT3 or TT. I talked to several people who have the IPD plenum and they were very pleased with it. I am more interested in the plenum as it can be machined to fit the X51 throttle body, any thought on this?? Dave I'm really surprised that IPD didn't make a specific plenum for the X-51 T/body w/ the standard intake runners. If their standard 997 item can be machined than it's the perfect conversion kit to get this part and the X-51 airbox to work with the rest of the intake system. The only (major) problem I see is the mapping. There's one very obvious one and one that isn't so obvious. The obvious one is the alpha-n mapping in the ECU - this will be off by miles. This map replaces the MAF sensor signal with a table of pre-defined signal values based on throttle angle and rpm if the MAF fails. The amount of air going into the engine at a given throttle angle will be way more with a bigger t/body so the car would run mad lean. I don't know if this alpha-n map has any function with a MAF connected. The less obvious one is that all the other maps in the ECU derive their target lambdas and ignition values from throttle angle and rpm. I'm concerned you'd need a serious remap if you used the X-51 t/body as I don't believe the standard maps would work any more. An example. Your map for 20% throttle and 3000rpm returns a timing value of (let's say) 38 deg btdc. This works fine with the amount of air going in at 20% throttle opening with the standard t/body. With the X-51 t/body, a 20% throttle opening might let in as much air as (again, let's say) a 25% throttle opening with the standard t/body but would still pick up on the same ignition value as it would with the standard t/body. As you let more air into an engine, it needs LESS timing so our 38deg btdc may now be 5-6 degrees too much. The knock sensors would then kick in and you'd lose (a LOT of) power - maybe to the point of throwing a CEL. It may also be that with a 25% opening on the standard t/body, the map asks for a richer mixture. This wouldn't happen with the X-51 t/body as the ECU would still use the 20% value, running the car too lean and exacerbating the problem. Swapping throttle bodies just isn't a simple exercise in a Motronic car!! Anyone else care to comment on the above? Ian, there is a memeber on this site that did just what I wanted to do, which is use the IPD plenum with the larger X51 throttle body. He is running OEM software with no issues. That doesn't mean he isn't running lean though. Also, even though it is a motronic car the 02 sensors are gross adjusters so they should be able to adjust accordingly from my understanding, after all that's the point of a MAF vs. a Speed Density system. Unfortunately not to many people are aware of the differences between the X51 and non X51. As ususal always love your input... Cheers.. Dave

7mm front, 15mm rears. Dave

Sad to see you getting rid of the S, I read on 6speed that you were considering a GT3 or TT. I talked to several people who have the IPD plenum and they were very pleased with it. I am more interested in the plenum as it can be machined to fit the X51 throttle body, any thought on this?? Dave

Yea Wanyne mentioned machining, but machining what. A new bolt pattern, larger throttle area (this is a given). RSS wants $300 to machine a plenum. That's kind of outlandish. Maybe I can do it myself. Dave Dave, I think they would have to machine one of their plenum's. Not only for the four ne mounting holes but the opening is 4-6MM bigger too. The stock Plastic Plenum would not work. David Thanks Dave, I knew the OEM plastic plenum wouldn't work, but just how much work would it be to machine the RSS piece. I may drive down to RSS as Greg says he has a 997 X51 throttle body there so I can see. Dave

The only thing I can think of as the car warms up so does the electrical system, therefore causing greater resistance. This is common for cars with that kind of mileage on the car and could be just as simple as a bad starter cable or other electrical issue along those lines. Dave

Yea Wanyne mentioned machining, but machining what. A new bolt pattern, larger throttle area (this is a given). RSS wants $300 to machine a plenum. That's kind of outlandish. Maybe I can do it myself. Dave

Ian any updates?? Dave

Thanks Loren..I was involved with that discussion. However it never was fully understood why the X51 throttle body was incompatible. If it's just the opening is larger than that can be changed. I was hoping one of the techs who are ont his site and maybe installed a X51package what is the difference.

I know the opening is larger..just wondering if the bolt pattern is the same. Dave

Is the bolt pattern the same and just the throttle opening is larger, anyone know? Dave

The car is really designed for 93 octane, even with Cali. 91 the car is losing 8-10rwhp. Dave

19X8.5 and 19X11..as far as the offsets I dont remember exactly but I think it was 57mm front and 52mm rear. Just keep in mind the offsets will be different for the rear wheels depending on NB or WB. If the wheels are actually off of a 997T than it is a widebody car and they will stick out a tad much on a NB car. Dave

Ian, glad to see you here as well and always look forward to your input. However, the X51 heads from my understanding are nothing more than some bowl work and a stiffer exhaust valve for the increased rpm to 7450rpm. The stock non X51 heads have to flow pretty darn good to get to 93hp/litre while limiting rpm to 7300rpm. In my own experience heads without updated cams and more rpm is probably at best 5-10rwhp and in my opinion are a total waste of money for what Porsche wants for the X51 heads. You layed out a good plan for getting the hp to at least X51 levels with only half or less of the expense. Obviously if you start with more power you will end up with more power. On 6speed we discussed that I was considering the intake manifolds from the X51 and I have to be honest, from the people I talked to I figured it wasn't worth the expense (as you thought) of going down this road for what will at best be 10rwhp for the huge expense. I will still do the X51 carborn air box as I think it is so pretty and really is not a bad investment for what it costs (a lot cheaper than some of the non OEM intakes out there) and only having to deal with cutting out the upper deck lid for the other inlet. Dave Dave - really good to see you on here too. This is one of the best forums on the 'net for Porsche owners and I wish more 6speeders would take the time to post (and contribute). I agree totally with your comments above - of all the intakes for the Mk1 997S, the X-51 is probably the best. However..... I've mailed Fabspeed today to beg them to produce a version of their (superb) high performance intake (that they only provide for 997S/2 currently) for the 997S/1. I'll be posting on 6speed about this soon too. Their new intake is the best I've ever seen and I think all us addicted modifiers would snap it up for our Mk1's! See you on 6speed again soon. Ian You too Ian... What software do you like?? After I do the intake I would like to do some software to tie it all together. I am leaning toward FVD, they are kind of expensive but the tweak to the numbers you email them. What's your thoughts?? Dave

Ian, glad to see you here as well and always look forward to your input. However, the X51 heads from my understanding are nothing more than some bowl work and a stiffer exhaust valve for the increased rpm to 7450rpm. The stock non X51 heads have to flow pretty darn good to get to 93hp/litre while limiting rpm to 7300rpm. In my own experience heads without updated cams and more rpm is probably at best 5-10rwhp and in my opinion are a total waste of money for what Porsche wants for the X51 heads. You layed out a good plan for getting the hp to at least X51 levels with only half or less of the expense. Obviously if you start with more power you will end up with more power. On 6speed we discussed that I was considering the intake manifolds from the X51 and I have to be honest, from the people I talked to I figured it wasn't worth the expense (as you thought) of going down this road for what will at best be 10rwhp for the huge expense. I will still do the X51 carborn air box as I think it is so pretty and really is not a bad investment for what it costs (a lot cheaper than some of the non OEM intakes out there) and only having to deal with cutting out the upper deck lid for the other inlet. Dave