enginerd Posted September 6 Report Share Posted September 6 (edited) Someone convince me that the Boxster VPI (475) is accurate/reasonable/logical or I will submit a request for VPI review. I put together a comparison table (hopefully the formatting holds) against two BMW builds. Correct me if I'm wrong on anything, and please please point out anything that I may have missed that would make the Boxster less good than these other categories. I don't want to go through the trouble of requesting a VPI change, so I want someone to help me out here and tell me how 475 is the right VPI. BMW e30 + M54 swap BMW e36 + Wing & Splitter Porsche Boxster + Wing & Splitter TCV 500 495 495 Rated HP 189 189 201 Fuel cell capacity 18.6 19.2 19.0 Curb Weight ~2800 3087 2822 Aerodynamics Brick Smooth Brick Airplane Handling Good Really good Really really good Looks like the boxster has more power, better handling, slipperier aerodynamics, roughly equal fuel, and similar weight compared to these other cars at 495 / 500 pts. Edited September 6 by enginerd 2 3 Quote Link to comment Share on other sites More sharing options...
Grufton Posted September 6 Report Share Posted September 6 (edited) Both BMW's listed were available with LSD's, which was not the case for the Boxster. Edit: you should know better than me, but I believe the E30/M54 is 184 hp. Edited September 6 by Grufton 2 Quote Link to comment Share on other sites More sharing options...
jmabarone Posted September 6 Report Share Posted September 6 (edited) Brakes are arguably better stock (I know it's "free" to upgrade) on the Boxster. ABS is likely better too. EDIT: No dog in this fight, not expecting to be duking it out with Boxster, e30s, or e36s down in F class. Edited September 6 by jmabarone 1 1 Quote Link to comment Share on other sites More sharing options...
ETR Posted September 6 Report Share Posted September 6 23 minutes ago, Grufton said: Both BMW's listed were available with LSD's, which was not the case for the Boxster. Edit: you should know better than me, but I believe the E30/M54 is 184 hp. I won't pretend to know anything about Porsche's beyond the 80's, but a quick googling mentions things of PCM and brake differential trickery on the Boxters for a limited slip effect. Thoughts? A potential benefit or the first thing a builder disables? Certainly couldn't hurt in the rain I suppose. Quote Link to comment Share on other sites More sharing options...
LuckyKid Posted September 6 Report Share Posted September 6 (edited) Unfortunately the best and most effective argument for the Porsche VPI is that other VPIs are even more messed up, then swap weights, then loop holes. By Page 7 everyone is too tired to really put pressure on resolving the issue. The power of framing! Sometimes people forget that they can actually eat a pizza, you just gotta start a slice at a time. Edited September 6 by LuckyKid 7 1 Quote Link to comment Share on other sites More sharing options...
the5 Posted September 6 Report Share Posted September 6 1 hour ago, enginerd said: I don't want to go through the trouble of requesting a VPI change, so I want someone to help me out here and tell me how 475 is the right VPI. Why don't you want to go through the trouble? It's probably easier than actually making this forum post to request it. What I do know Is I posted my cars weight and Dyno numbers and I know that it weighs more than e30's and some e36 and Makes less power than "M54" cars. I will add the TAC is actively reviewing Boxster VPI and requested me for data that I provided. We have set Fast laps of the event in the 24 Hour in the S2000, Boxster And Altima. Sometimes its not the car 4 Quote Link to comment Share on other sites More sharing options...
MattGent Posted September 7 Report Share Posted September 7 How about using as-raced weights and whp? And resulting pwr/wt. Some of this data has been posted here. OE curb weights are effectively useless for Champ. 2 Quote Link to comment Share on other sites More sharing options...
takjak2 Posted September 7 Report Share Posted September 7 I'm not a BMW insider, but I do know: The rear multilink suspension geometry of the e36 is much better than the strut on the boxster. Champcar boxsters suffer heavily from rear tire wear. BMW gear ratios and rear end are definitely better. Only a really tall and weak 5 speed is champ-legal for the boxster. I suspect if you plot usable and average wheel torque the BMW is stronger. The euro spec E36 has a stock oil cooler. Is anyone benefitting from that? The boxster does not. How much tire width is being commonly run on each? Is the IMS issue for boxsters a relevant discussion point? Stock oiling issues? 2 Quote Link to comment Share on other sites More sharing options...
jim161c Posted September 7 Report Share Posted September 7 6 hours ago, enginerd said: Someone convince me that the Boxster VPI (475) is accurate/reasonable/logical or I will submit a request for VPI review. I put together a comparison table (hopefully the formatting holds) against two BMW builds. Correct me if I'm wrong on anything, and please please point out anything that I may have missed that would make the Boxster less good than these other categories. I don't want to go through the trouble of requesting a VPI change, so I want someone to help me out here and tell me how 475 is the right VPI. BMW e30 + M54 swap BMW e36 + Wing & Splitter Porsche Boxster + Wing & Splitter TCV 500 495 495 Rated HP 189 189 201 Fuel cell capacity 18.6 19.2 19.0 Curb Weight ~2800 3087 2822 Aerodynamics Brick Smooth Brick Airplane Handling Good Really good Really really good Looks like the boxster has more power, better handling, slipperier aerodynamics, roughly equal fuel, and similar weight compared to these other cars at 495 / 500 pts. I made a similar comparison around a year ago. If you were to swap a 201 hp engine in to a e30 and you have a 506 pt car or 2+ laps. just an observation - I have no dog in this race. Quote Link to comment Share on other sites More sharing options...
enginerd Posted September 7 Author Report Share Posted September 7 1 hour ago, takjak2 said: The euro spec E36 has a stock oil cooler. Is anyone benefitting from that? The boxster does not. No, because only US/Canadian models are allowed. Quote Link to comment Share on other sites More sharing options...
LuckyKid Posted September 7 Report Share Posted September 7 11 hours ago, takjak2 said: The euro spec E36 has a stock oil cooler. Is anyone benefitting from that? The boxster does not. 1 Quote Link to comment Share on other sites More sharing options...
frankrehnelt Posted September 7 Report Share Posted September 7 11 hours ago, takjak2 said: Is the IMS issue for boxsters a relevant discussion point? Stock oiling issues? The IMS bearing in the 97 98 and 99 cars is not a big issue and has 0 point fixes if so inclined. 1 Quote Link to comment Share on other sites More sharing options...
Grufton Posted September 7 Report Share Posted September 7 3 minutes ago, enginerd said: The e36 325i never had an LSD (according to info on some bmw forums). Can you show otherwise? I was under the impression that teams were claiming a "winter package" option that had an LSD. I have no documentation to support this either way however. Quote Link to comment Share on other sites More sharing options...
enginerd Posted September 7 Author Report Share Posted September 7 2 minutes ago, Grufton said: I was under the impression that teams were claiming a "winter package" option that had an LSD. I have no documentation to support this either way however. Oh, yea looks like you are right. Someone on a different forum says it was a sport option until '96 Quote Link to comment Share on other sites More sharing options...
Wheelman_99 - C Rallo Posted September 7 Report Share Posted September 7 (edited) What's the power to the wheels for the BMW's? E36, 944 and many/most other cars dust the Boxster in a straight line and the 944 is at 23.5 gallons IIRC. If not power, then it is gearing? There are certainly many gearing options open for the BMW's The only really fast Boxsters are pro built, pro driven and are on sticky tires. In another series, it is almost impossible/pointless for anyone but the top driver and top team in the category to run certain cars, because the cars they run have been nerfed heavily. Let's not ruin a reliable, fun and popular platform for everyone else. While we are on the subject of VPI, what is the base formula? Edited September 8 by Wheelman_99 - C Rallo 2 Quote Link to comment Share on other sites More sharing options...
enginerd Posted September 7 Author Report Share Posted September 7 (edited) 1 hour ago, Wheelman_99 - C Rallo said: The only really fast Boxsters are pro built, pro driven and are on sticky tires. In another series, it is almost impossible/pointless for anyone but the top driver and top team in the category to run certain cars, because the cars they run have been nerfed heavily. Let's not ruin a good platform for everyone else. You are describing every boxster in the series, yes? Are there any boxsters that aren’t top tier because I don’t know if any. Why does this “let’s not ruin a good platform for everyone else” argument always come up? How many points added would “ruin” the boxster? It is currently 475. TAC originally recommended 500. Is the platform “ruined” at 500? Is it ruined if the value was raised to 480? 490? How many times in the last 5 years has a car had the value raised so much that it is “ruined” in an attempt to corral performance? [edit] this argument always reminds me of wife talking. We have a 3 hour delay on the flight going to our 10 day vacation: “this is a nightmare! Our vacation is ruined!!” Edited September 7 by enginerd 1 3 Quote Link to comment Share on other sites More sharing options...
jWashburn Posted September 7 Report Share Posted September 7 (edited) TL, DR; E30 should be 441 E30 with 189hp should be 479 (as lbs/hp performance trendline not swap math) Boxster 2.5 should be 496 944s should be a lot higher, based on lbs/hp and especially FUEL (lbs/gals -or- mass/energy) The RWD (3) is what the new VPI "should" be, this is created by the trendline of all the input cars. I did this a few months ago and applied some changes, by what "input" cars are used the trendline will change a lot. So yeah, there is a bull cookies factor. I used the E30 as an input 8 times, this sets it as an "absolute truth", by doing this the trendline will not be greatly influenced by less popular cars. Another thing that I have not resolved is that all cars are going to use up 48.5 horsepower going 100mph, so the lbs/hp should account for the 48.5 hp loss. Oh, when I didn't use the 8 times E30 input the; E30 should be 432 Boxster 2.5 should be 490 944 awesome lbs/gal, E36 and E46 bad lbs/gal. Edited September 7 by jWashburn 1 Quote Link to comment Share on other sites More sharing options...
tyler_j Posted September 7 Report Share Posted September 7 2 hours ago, Wheelman_99 - C Rallo said: E36, 944 and many/most other cars dust the Boxster in a straight line and the 944 is at 23.5 gallons IIRC. If not power, then it is gearing? Weight possibly? I do not have experience gutting a Boxster but E30, E36 and 944 all can get pretty light in champ form. Being newer and a convertible maybe the Boxter has less weight that can come out? Again no boxster race experience but I have had a street Boxster, Street e30s and ran an e30 and e46 in champ (along with just about anything else that I can rent haha). The Boxster gearing seems to be a lot more street oriented while the BMW gearing translates to track a lot better. Boxster felt good cruising but I felt the ratios were a bit stretched in the trans and rear end a bit too tall. Just my 2cents on driver feel. Side note: lift-off oversteer on street suspension with street tires is a real thing, a decreasing radius downhill exit ramp just about ended that car. 1 Quote Link to comment Share on other sites More sharing options...
wvumtnbkr Posted September 7 Report Share Posted September 7 22 hours ago, the5 said: Why don't you want to go through the trouble? It's probably easier than actually making this forum post to request it. What I do know Is I posted my cars weight and Dyno numbers and I know that it weighs more than e30's and some e36 and Makes less power than "M54" cars. I will add the TAC is actively reviewing Boxster VPI and requested me for data that I provided. We have set Fast laps of the event in the 24 Hour in the S2000, Boxster And Altima. Sometimes its not the car Aren't all 3 of those cars are / have caused controversy for being too fast? Quote Link to comment Share on other sites More sharing options...
enginerd Posted September 7 Author Report Share Posted September 7 11 minutes ago, wvumtnbkr said: Aren't all 3 of those cars are / have caused controversy for being too fast? Not S2000 unless I missed something. I’d be very surprised if an S2000 won anything other than fast lap in an endurance race with ChampCar fuel rules. Quote Link to comment Share on other sites More sharing options...
wvumtnbkr Posted September 7 Report Share Posted September 7 I should clarify, when the s2000 was added to the vpi list, people claimed that champcar "jumped the shark". This IS in relation ti fast lap only btw. Quote Link to comment Share on other sites More sharing options...
the5 Posted September 7 Report Share Posted September 7 3 hours ago, wvumtnbkr said: Aren't all 3 of those cars are / have caused controversy for being too fast? Sure, I guess it just so happens that we are the team that ran them all. there have been other teams that ran S2000, Boxster and Altimas but we are the only ones setting FTDS Quote Link to comment Share on other sites More sharing options...
jWashburn Posted September 8 Report Share Posted September 8 Boxster FTD just last month: https://beta.speedhive.com/sessions/7883176 Quote Link to comment Share on other sites More sharing options...
wvumtnbkr Posted September 8 Report Share Posted September 8 (edited) 2 hours ago, the5 said: Sure, I guess it just so happens that we are the team that ran them all. there have been other teams that ran S2000, Boxster and Altimas but we are the only ones setting FTDS I hear ya. It's not always the car. Altimas, specifically created a kerfuffle by winning almost every race it entered a few years ago. Setting a few ftds along the way. It got a vpi change like the day before Daytona 3 or 4 years ago. Didn't other teams with boxsters set ftds at a few a races? Edited September 8 by wvumtnbkr Quote Link to comment Share on other sites More sharing options...
Hugh Jass Posted September 8 Report Share Posted September 8 1 hour ago, wvumtnbkr said: I hear ya. It's not always the car. Altimas, specifically created a kerfuffle by winning almost every race it entered a few years ago. Setting a few ftds along the way. It got a vpi change like the day before Daytona 3 or 4 years ago. Didn't other teams with boxsters set ftds at a few a races? not if @the5 was there 1 1 1 Quote Link to comment Share on other sites More sharing options...
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