C2 vs C4
05-25-2006, 02:54 PM
#1
Rennlist Member
Thread Starter
C2 vs C4
I am sure this is not a new question, but my search did not find anything.
Is there a noticable difference in how a stock C2 and stock C4 drive on the track? My assumption is that more understeer with C2 vs C4. Is this a lot more noticable?
Is there more maintanance required for C4 compared with C2 with track use? I am particularly wondering about the AWD system.
I see that PCA weight for C4 is 166lbs more than C2 which should not make a big difference for DE.
Thanks
Is there a noticable difference in how a stock C2 and stock C4 drive on the track? My assumption is that more understeer with C2 vs C4. Is this a lot more noticable?
Is there more maintanance required for C4 compared with C2 with track use? I am particularly wondering about the AWD system.
I see that PCA weight for C4 is 166lbs more than C2 which should not make a big difference for DE.
Thanks
05-25-2006, 05:06 PM
#2
Burning Brakes
I will take a stab at this. If you haven't gotten Adrian's book get it.
The general rules for the STOCK setups on the cars:
1. C2 is ever-so-slightly lighter and quicker on the straights
2. C2 tends to oversteer more ( or understeer less ) than C4 (that means the rear of the car tends to swing out more on the C2) - Yes, it is noticeable when you are at 9/10ths but I don't think you need to be anywhere near 9/10ths if we're talking about your first DE or two, depending on your skill level
4. In the hands of an expert driver, a C2 will corner a little better than a C4 in good track conditions, but in bad track conditions (mud, water, gravel, etc) the C4 corners better than the C2.
OF course you can throw all these out the window when you start tinkering.
I would also recommend "Speed Secrets" and "Speed Secrets 2" by Ross Bentley - they are mainly about racing but he gives a great introduction to how the car's setup and your driving style will affect the handling characteristics.
The general rules for the STOCK setups on the cars:
1. C2 is ever-so-slightly lighter and quicker on the straights
2. C2 tends to oversteer more ( or understeer less ) than C4 (that means the rear of the car tends to swing out more on the C2) - Yes, it is noticeable when you are at 9/10ths but I don't think you need to be anywhere near 9/10ths if we're talking about your first DE or two, depending on your skill level
4. In the hands of an expert driver, a C2 will corner a little better than a C4 in good track conditions, but in bad track conditions (mud, water, gravel, etc) the C4 corners better than the C2.
OF course you can throw all these out the window when you start tinkering.
I would also recommend "Speed Secrets" and "Speed Secrets 2" by Ross Bentley - they are mainly about racing but he gives a great introduction to how the car's setup and your driving style will affect the handling characteristics.
05-25-2006, 05:11 PM
#3
Burning Brakes
C4 has loads more understeer than a comparably setup C2 - all due to the traction control computer taking over control whenever it senses the rear end sliding out a bit. However a nicely setup C4, lowered, corner balanced, aligned, stiffened suspension will be a great handling car on big tracks. On smaller tighter autox tracks the C4 will definitely push more. You can "lift-throttle" oversteer a C4 almost as well as a C2 but you can not "throttle on" oversteer a C4. There are several guys on this board that race and track C4s. I autox'd and TT'd my previous C4 Cab and it was loads of fun.
Not much more maintenance with the C4 as long as everything is working well, there is the potential to need to rebuild the center diff. but that is rather uncommon. C4 also has 4 piston rear calipers for all years, the C2 had 2 piston calipers up until 92 or 93 - they can upgraded to the C4 caliper though.
Guys on the board you may want to contact at Garret376 and KGorman.
Not much more maintenance with the C4 as long as everything is working well, there is the potential to need to rebuild the center diff. but that is rather uncommon. C4 also has 4 piston rear calipers for all years, the C2 had 2 piston calipers up until 92 or 93 - they can upgraded to the C4 caliper though.
Guys on the board you may want to contact at Garret376 and KGorman.
05-25-2006, 08:58 PM
#4
Drifting
I am a novice driver, so take the following with that in mind..
I have an '89 c4 which does not have airbags, so I am a bit lighter than a 90+ C4. So this brings it closer to the C2 in terms of weight. I have lightened mine up by about 300lbs, so I am lighter than many C2's I see out there.
The C4 has many handling benefits imho, and frankly just makes me look like a better driver in most cases. The areas I notice the most are, I can brake later and in many cases get on the gas sooner. This effect eclipses most benefits of lower weight, especially in type 1 turns (turns leading to a straight). The C4, as was already noted, is much better in adverse conditions. I also suspect much better in standing start situations as well.
Out on the track, I generally notice very little difference when following C2's and RSAs other than driver skill. I think at my level, the car is not so much a factor, and more how I can control what I am driving, and how I drive in general. That said, since the C4 inspires confidence, I might tend to be faster in it. Then again, perhaps I am learning bad lessons. I try to keep an eye out for that. Most of the time I hang just fine with C2's and RSAs given all else is equal.
In terms of understeer, I got most of that out of the car using new suspension, camber, and sways. Now the car is pretty neutral. I see lots of C2 and RSA cars with oversteer, and generally that is my time to pass. ;-).
The mods for the C4 are pretty much the same as for the C2 except a few isuses like short shifter availability, etc.
The C4 does not have an LSD, but rather a PDAS system that makes the rear end into a solid axle under slip conditions. It induces understeer, and boy does it. The car has great rear brakes and the ABS is very usefull. Here is a recent thread regarding Garretts experience without PDAS and it's effect on handling:
https://rennlist.com/forums/964-forum/274859-driving-the-snot-out-of-the-c4-on-the-track-interesting-findings.html
In this thread I explored mods and resale regarding the C4, there is some good info here:
https://rennlist.com/forums/964-forum/274063-the-slope-and-resale.html
For me, I really was not looking for a C4 per-se. I was mainly focused on getting a nice car in good condition and I would take it from there. I am glad however I ended up with the C4. It's a great car on the track, and a great car to learn how to drive better. I suppose at some point I will be in a rear-drive pcar, but thats probably not until I am looking at a gt3 or something much more serious.
Garrett is a huge wealth of info, I am sure he will chime in with some goodies.
I have an '89 c4 which does not have airbags, so I am a bit lighter than a 90+ C4. So this brings it closer to the C2 in terms of weight. I have lightened mine up by about 300lbs, so I am lighter than many C2's I see out there.
The C4 has many handling benefits imho, and frankly just makes me look like a better driver in most cases. The areas I notice the most are, I can brake later and in many cases get on the gas sooner. This effect eclipses most benefits of lower weight, especially in type 1 turns (turns leading to a straight). The C4, as was already noted, is much better in adverse conditions. I also suspect much better in standing start situations as well.
Out on the track, I generally notice very little difference when following C2's and RSAs other than driver skill. I think at my level, the car is not so much a factor, and more how I can control what I am driving, and how I drive in general. That said, since the C4 inspires confidence, I might tend to be faster in it. Then again, perhaps I am learning bad lessons. I try to keep an eye out for that. Most of the time I hang just fine with C2's and RSAs given all else is equal.
In terms of understeer, I got most of that out of the car using new suspension, camber, and sways. Now the car is pretty neutral. I see lots of C2 and RSA cars with oversteer, and generally that is my time to pass. ;-).
The mods for the C4 are pretty much the same as for the C2 except a few isuses like short shifter availability, etc.
The C4 does not have an LSD, but rather a PDAS system that makes the rear end into a solid axle under slip conditions. It induces understeer, and boy does it. The car has great rear brakes and the ABS is very usefull. Here is a recent thread regarding Garretts experience without PDAS and it's effect on handling:
https://rennlist.com/forums/964-forum/274859-driving-the-snot-out-of-the-c4-on-the-track-interesting-findings.html
In this thread I explored mods and resale regarding the C4, there is some good info here:
https://rennlist.com/forums/964-forum/274063-the-slope-and-resale.html
For me, I really was not looking for a C4 per-se. I was mainly focused on getting a nice car in good condition and I would take it from there. I am glad however I ended up with the C4. It's a great car on the track, and a great car to learn how to drive better. I suppose at some point I will be in a rear-drive pcar, but thats probably not until I am looking at a gt3 or something much more serious.
Garrett is a huge wealth of info, I am sure he will chime in with some goodies.
05-25-2006, 09:10 PM
#5
Rennlist Member
I've posted some stuff previously, which I'm sure you can find by searching. I tracked a '92 C4 extensively (not raced) in '00 and '01, then RSA #1 (including racing) in '02 and '03, until it met its demise.
In brief, when either car is set up in DE mode (v. stock/prepared class racer) the C4 does have a basic tendency to push. But that's OK. Just figure out what you're trying to accomplish and go from there.
Just to compare numbers, the RSA (which was about 350 lbs lighter, ran higher spring rates, and slightly wider Hoosiers) was about 4 sec/lap faster @ Thunderhill. Mid 2:03's to mid 2:07's for the full course.
Ken
In brief, when either car is set up in DE mode (v. stock/prepared class racer) the C4 does have a basic tendency to push. But that's OK. Just figure out what you're trying to accomplish and go from there.
Just to compare numbers, the RSA (which was about 350 lbs lighter, ran higher spring rates, and slightly wider Hoosiers) was about 4 sec/lap faster @ Thunderhill. Mid 2:03's to mid 2:07's for the full course.
Ken
05-25-2006, 09:18 PM
#6
Burning Brakes
Those were my sentiments exactly before I edited my post - about just getting the right 964 regardless of C2/C4 and not getting too hung up on the over/understeer of C2 vs. C4. The "good" 964s are hard to find so just get the best deal and learn to drive what you got - if you're serious about learning to be a performance driver you need to learn AWD, RWD, FWD, front engine, mid engine, rear engine, karts, wings, etc. anyway so just jump in and learn - you likely have years to go before you're "really good". Sounds like you're still at square one so just get a good car in good shape that's priced right and gives you a boner. Then drive the crap out of it until you can do it blindfolded.
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05-25-2006, 10:01 PM
#8
Burning Brakes
Hard braking disable the C4s PDAS system so that will overcome some of the push but yu need to be braking hard enough to get into the ABS I believe. A good suspension setup and alignment will reduce the push on entry very well.
Ihave just gone from 5 years of autox and track in my C4 to a 1980 911SC so I will very soon find out justhow much the computer control on the C4 was helping or what bad habits is was hiding.
Ihave just gone from 5 years of autox and track in my C4 to a 1980 911SC so I will very soon find out justhow much the computer control on the C4 was helping or what bad habits is was hiding.
05-26-2006, 01:46 AM
#9
Drifting
Originally Posted by chancecasey
Ken - does a little harder trail braking reduce the C4's push in entry?
05-26-2006, 02:08 AM
#10
Rennlist Member
I'm not a big trail braker. Something about starting out way back in the stone age with a '68? So I end up with this C4 that had Euro RS Bilsteins/Eibach/Cup Bars and just kinda hammered on the thing because it was the only running Porsche I had at the time. Set the bars full soft front, full stiff rear and it drove fine. Some power on understeer, a bit heavy for my taste on turn-in and mid-corner. Predictable, but heavy.
As far as 2 @ Laguna (we can only wish we are discussing the REAL 2!), yeah I'm braking as hard into the corner as I dare. Never ever seem satisfied, no matter what car! I'm much more of a 2 or 6 @ Thunderhill for feeling out a car.
So to wrap it up and get to the point of the original inquiry: you can certainly dial out the front end washing out understeer with some basic alterations from stock.
Oh, and as far as care and feeding, the only extra thing I found was a tendency for the brake fluid reservoir to slosh around somehow under hard uphill braking (1 and 3 @ Willow), causing a lack of the hydraulic assist for the brake booster. Learned to keep the fluid topped up and all was well!
As far as 2 @ Laguna (we can only wish we are discussing the REAL 2!), yeah I'm braking as hard into the corner as I dare. Never ever seem satisfied, no matter what car! I'm much more of a 2 or 6 @ Thunderhill for feeling out a car.
So to wrap it up and get to the point of the original inquiry: you can certainly dial out the front end washing out understeer with some basic alterations from stock.
Oh, and as far as care and feeding, the only extra thing I found was a tendency for the brake fluid reservoir to slosh around somehow under hard uphill braking (1 and 3 @ Willow), causing a lack of the hydraulic assist for the brake booster. Learned to keep the fluid topped up and all was well!
05-26-2006, 10:28 AM
#11
Rennlist Member
Thread Starter
It appear that there are not a significant differences between C2 and C4, especially in maintanance, with the exception of better handling of C4 in New Jersey snow.
The 964 will be more of a street and occasional DE car with my wife as the primary driver. Of course, I will also have to use it for DEs, becasue I will save a lot of money in gas not towing a car to the track.
(my track car is a 944S2 which has been turned into a PCA/NASA club racer as of this year). Given that I am still developing the race car, this car will have to remain stock for the forseeable future which I see as an opportunity to develpo my driving skill. I guess DE insurance is a must to overcome my inhibitions when I drive it on the track.
I have found two cars. One a C4 and the other a C2. Both 90. Based on conversation with the owners, the C2 is a little nicer with only 72K miles and engin rebuild (sounds like top and rings) around 50K probably due to head leak. I will have a better idea of what was done when I get the records faxed this weekend.
The C4 has 100K on it with new clutch. From the pictures, the car looks good inside (better than C2) and out (same as C2) and is about $2500 cheaper than the C2. Recent clutch, but no major engin work. No oil leak and the oil usage is about 1 qt per 2-3K which sounds resonable.
I hope to see both next weekend.
Nader
The 964 will be more of a street and occasional DE car with my wife as the primary driver. Of course, I will also have to use it for DEs, becasue I will save a lot of money in gas not towing a car to the track.
(my track car is a 944S2 which has been turned into a PCA/NASA club racer as of this year). Given that I am still developing the race car, this car will have to remain stock for the forseeable future which I see as an opportunity to develpo my driving skill. I guess DE insurance is a must to overcome my inhibitions when I drive it on the track.I have found two cars. One a C4 and the other a C2. Both 90. Based on conversation with the owners, the C2 is a little nicer with only 72K miles and engin rebuild (sounds like top and rings) around 50K probably due to head leak. I will have a better idea of what was done when I get the records faxed this weekend.
The C4 has 100K on it with new clutch. From the pictures, the car looks good inside (better than C2) and out (same as C2) and is about $2500 cheaper than the C2. Recent clutch, but no major engin work. No oil leak and the oil usage is about 1 qt per 2-3K which sounds resonable.
I hope to see both next weekend.
Nader