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YOUR RESEARCH996 C2 street to track??
Reported or suspected cause
very heavy connecting rods
Reported cause
No successful repair reported for this finding.
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Identified cause
0
Suspected cause
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Reported cause
One builder has told me most of the rev resistance on the M96/97 is due to the very heavy connecting rods.
Leading evidence: 'very heavy connecting rods' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'very heavy connecting rods' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Install 1/2 qt sump extension + x-51 baffle' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed
I had installed a 1/2 qt sump extension + x-51 baffle....
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My car had an LSD installed by a previous owner, I have been told that makes a big difference in these cars but I don't know the difference since I've never drive one w/o it.
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Performed · outcome unconfirmed
New LCAs...I think Dundon installed GT3 though don't remember.
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My car had an LSD installed by a previous owner, I have been told that makes a big difference in these cars but I don't know the difference since I've never drive one w/o it.
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Suggestion
If you're going to be running longer events, then I think there are possibly more considerations you'd want to take to make sure the car can deal with the extended heat and loads that are going to come from that on the drivetrain and brake systems.
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Outcome without a verified action link
+1 on the sump...I had the X51 baffle alone and it did not help.
Hey Guys,
I've been racing Spec Miata for several years and recently sold my car. I have an '03 996 C2, that I am considering converting to a dedicated track car. It already has JIC adjustable coil overs, cup sway bars, TRG end links. Besides the obvious, installing a deep sump kit and baffle, IMS update (which has not been done and there's 110K on the odometer), what else is recommended? I know a lot of guys DE their 996's but how viable are they as race cars? How are they on tires and what is the flavor of choice? How about brake pads and wear? I know that this will be a much more expensive endeavor than a Miata, but racing never has a finish line in terms of dollars spent. I appreciate your comments. - Mike
I have built my 2003 996 C2 as a DE car. I trailer it to the track but it still has license plates and I occasionally drive it on the street, but rarely now.
Here's a list of most of what I have done:
All poly suspension bushings
Solid rear subframe bushings
Wevo semi solid engine mounts
Function First transmission mount insert
Feal 996 C2 coilovers with monoball top mounts (adjustable front top mount) 7K front / 11K rear
GT3 sway bars front and rear with Tarrett drop links
Cup car ride height
Alignment set to -3 camber front and -2.5 camber rear, zero front toe, slight toe in rear
GT3 Euro seats
Schroth GT3 6 point harnesses
Agency Power bolt in roll bar
997 GT3 shifter
997 GT3 master cylinder
Rebuilt all calipers w/ stainless steel pistons and running Ferodo DS1.11 pads with stock ATE rotors
IPD plenum and 997 GT3 throttle body
LN Engineering 2.5 quart deep sump with 997 return tubes and pickup extension, as well as skidplate.
DCT flat bottom large diameter steering wheel
Odyssey 925 lightweight battery in Rennline aluminum mount w/ shut off switch
SoloDL lap timer connected to SmartycamHD mounted on roll bar
Rennline track mats metal floor mats
I have 3 sets of Oz Racing wheels in 18x8.5 front and 18x12 rear. I have Hoosier R7s on two of them and Pilot Sports on the third set for rain tires.
I run Joe Gibbs XP9 oil for the track. Unfortunately it only lasts 750 miles. This has been less of an issue now that I trailer to/from the track.
My car had an LSD installed by a previous owner, I have been told that makes a big difference in these cars but I don't know the difference since I've never drive one w/o it.
Hope that helps.
I have thought about it but I don't see my temps get that high really. I do have the low temperature thermostat from LNE installed. Even last summer with ambient temps pushing 100 at the track I didn't feel like the coolant temps were high enough to be concerned about. Maybe I'll put one in the next time I flush the coolant but not in a rush.
You have the 3.6, which I believe has better head cooling. My understanding is that head cracking is more common on the 3.4. I am not sure what the actual difference is though.
When you say "race car", what is the duration of the events you'll be running? Are we talking DE, or longer races? For DE I think the cars are good to go from the factory, and any improvements you make are just icing on the cake. If you're going to be running longer events, then I think there are possibly more considerations you'd want to take to make sure the car can deal with the extended heat and loads that are going to come from that on the drivetrain and brake systems.
I'm on the same path as you. Miata race car for competition and I recently built a '99 c2 996 for a track day car. While I'm still in the process of sorting the suspension on the Porsche (spec 996), my impression was that both of the cars are quite similar; in that both had to be driven as a momentum car. I expected the 996 to be able to really power out of the corner... but was surprised at how the weight of the car really slowed it down. Mine is not nearly as nimble as my sorted Miata, nor is it as fast. I hope to improve on this as I learn the particulars of running this platform... but,after my first time out last week, I was quite humbled.
+1 on the 2qt sump. I had installed a 1/2 qt sump extension + x-51 baffle.... even on re71r's the oil pressure was dropping in the corners.
+1 on the short shifter as the oem shifter is not very quick.
Also, you'll need a good seat as the oem seats don't restrain you well.
You'll have to ask Splitting Atoms about how to fit wide Hoosiers inside the front fender wells without shredding them on the radiator bracket... I suspect he uses an adjustable caster puck in the lca's to help center the tire in the wheel well.
I'll have to say the LSD made my car a whole different ballgame. Having read many of Slakker's racing exploits, and descriptions of cornering teqniques, I was not able to understand his perspective. That is, until I added LSD. Changed the way I drive it for sure. Enormous improvement in trail braking corners. It is the way these cars are meant to corner. Eye opening. Can't wait to get back out there
+1 on seats and harnesses, I can drive with the wheel instead of hanging on to it.
As far as tires, I'm still having fun on 225F and 255R 17". But I'll step up to 245F 275R 18" for my next set (NT01). I believe that is what the spec guys are running. Also note I'm on OE row030, so a little suspension limited.
+2 on seats and harnesses....before that I felt like I might fly out the door on corners even w/ sport seats.
FWIW I am running 245 fronts and 315 rears for tires.
I don't see any mention of a LWFW, underdrive pulley or aftermarket CIA.
Did you fellas do these or pass on them?
Any pictures?
My 2003 996 Carrera Aero
Complete Techart/Bilsten Suspension including front strut brace, sway bars and Tarret Drop links.
Dassport Roll bar
Cargraphic 3 piece 18x9 and 18x11 w/ Sumitomo 245 and 295
IPD Competition Plenum w/ GT3 TB
BMC Filter
997 Updated coils
Tarret X51 oil baffle
Kline equal length headers
200 Cell X pipe
Tubi Mufflers
RSS semi solid motor mounts
RSS underdrive pulley
Evoms Stage IV Tune
Rennline aluminium floor mats
Rennline hood protectors
Rennline tow hook
Rennline front grill screens
Numeric Shifter
Numeric Cables
Aasco LWFW
Sachs Stage II sprung clutch disc and Pressure plate
Techart flat bottom steering wheel
ECS Stainless steel rubber coated brake lines
Dyno @ 297 RWHP
26 MPG on 93 pump gas
Daily Driver, Autocross and DE car
M96 experts say don't do a LWFW unless you have a built engine with the FW balanced to the crankshaft and the #6 bearing reinforced. Without doing so you risk a broken crankshaft.
I have also built my 996 Aero to be pretty much a dedicated (but streetable) DE car with 55K miles... I love the 996 platform. Here is what I did:
997S Engine and transmission with Drexel adjustable LSD (somewhere about 400HP)
LWFL and performance clutch
DUNDON custom exhaust with 4 pipe headers, catless and turbo muffler
996.2 Instrument cluster and Environmental control unit
Custom ECU harness
Ohlin R&T GT3 Suspension (got rid of JRZ Double adjustable)
996 Turbo Radiators + center
All calipers rebuilt and refinished
Dundon DME/ECU Tune
Agency rollbar and 5 point harnesses.
996.2 ABS
Euro 996 GT3 seats
GT3 wheels (one set for street and one set for track tires)
GT3 console delete
997 shifter
996.2 rear bumper (love how it integrates with Aero look)
Complete repaint.
Amberectamy (removal of all amber from headlight)
Brembo Big brake Kit.
GT3 sway bars
New LCAs...I think Dundon installed GT3 though don't remember.
First time on track since rebuild on APril 20
I have looked into doing a 4.0 build on my car... One builder has told me most of the rev resistance on the M96/97 is due to the very heavy connecting rods. Removing material from them during balancing is said to really help rev-ability.
The difference in engine rpm acceleration on my car when LWFW and underdrive pulley was installed was substantial.
You can listen to the revs, but they were all limited to 5000 rpm, the tune has a 5000 rpm launch control, when the car is not moving (0 mph) the revs keep banging off the 5k limiter
https://youtu.be/d4dTEMOe_2s
Thanks...You'll also note that I opened up the inlets so I get more air in the radiators since they are
50% larger without side by side comparison it looks stock.
The stock 996 is a great race car. The PCA Spec class for the 996 [SP996] is pretty competitive and times are very quick. If you are interested, you should take a look at the rules over there (and if you really want to race), take some steps to upgrade your car into a true racer in a very competitive class. Make sure you don't upgrade your car out of the class with things that are illegal. BF Goodrich R1s run fast and are the spec tire.
-td
OS Giken LSD. I got a great deal from an awesome active member on this board. Got the whole transaxle, added a new clutch and pp, and had my indy install so it would be in for my DE.
I had wondered about the light weight flywheel also. I believe the dual mass flywheel, while heavy, is also important as a vibration damper for the rotating assy. I wonder if Porsche Motorsports or other (ACT?) might offer a harmonic balancer for the nose of the 996 crank? ...perhaps it could incorporate a smaller diameter pulley to keep the power steering fluid from boiling.
dkraige,
When referencing a "race car", I'm referring to sprint races. 20 or 30 minutes. I'm only used to SCCA or NASA Club Racing formats. I'm not familiar with the PCA Club Racing format, but I assume they are similar.
Great advice guys, and I really appreciate it. I'm going to dig into the Spec 996 rules and start assessing the "damage" to go that route. At the very least, I am going to start prep for DE. Look forward to seeing some of you at Sebring in the near future!
At that race length I don't think you're going to have a lot of issues. I run that long in DE sessions and have no issues on a more or less stock car. Spend your money on some good tires!
No issues that I've seen with dedicated race cars. All of the SP996 guys I know run them.
As for the OP and his build, look at the SP996 specs in the 2018 PCA club racing guide. Then go look on rennpoints for the SP996 track record at your favorite track. I think you'll be amazed at how quick they are for the money.
Have you not had any issues with oil pressure dropping on long sweeping turns like a lot of 996s have? I know some
folks still have that problem even with a deeper sump, pickup, etc.
I am super glad that my transaxle and LSD is working out so well and someone could take advantage of it. As you know it was all virtually new. With some work my 997 Tranny is really working for me too.
This is exactly what caused my engine to grenade last season. I did not take this serious and paid for it.
