LA964RS

I've got to agree here. 2 through 5 short as possible for the new engine rev range and the big 6th for highway. The difference with the short gears feels like an add'l 50 or more HP as the car just pulls right in each gear.

Again, you may want to consider keeping the engine pretty stock and putting more $$ into the gearbox. Stock engine will run forever w/no probs. Start doing a lot of mods and you increase the possibility of some drama somewhere in the unit...especially if its not a throughly designed unit...ie, cams match the chip and the headers and the intake and the head, etc. etc.

JasonAndreas

I thought I saw on the 993 forum that they ran some simulations and timed tests and figured out that regearing a car that is driven mostly on the highway is a complete waste of money? It feels faster but when you go to measure it isn't.

Tom W

Jason, It was that the 0-60 times were not much better (if at all) due to the extra shifts. On the track it's a much different matter as you can stay in the power band much easier. Not too many people drive on the street at 4.5k-6.8k rpms.

I do believe that it's a ton of money for not much benefit (other than fun) on the street. However, there are a lot of folk spending a ton of money on cosmetics for a street car, so everyone makes their own decision as to it's worth.

tonytaylor

Short gears work well on track because the max speed you can acheive is relatively low, I don't get over 120mph at my local, hence having 3 usuable gears in that range rather than 1 or 2 is an advantage. On the street the max speed may be whatever the car can acheive and the gears are best spread out through this larger range - which is typicaly how the stock box is geared. Short gears feel faster in their sweet spot but you lose out elsewhere. Personaly I wouldn't re-gear a street car.

The lightweight flywheel is another track based mod that goes well with lower gears and lots of gear changes. At the top speed end the benefits of a light flywheel are at best marginal.

I run a MAF/chip/enlarged throttle body and it gives just under 300bhp@flywheel and, apart from one episode caused by a different service center, has been totaly reliable, was cheap for the hp and gives better engine drivability than stock. The key was it was fitted by someone who designed the complete package and really knew what he was doing.

The length of the headers tunes the engine for a certain part of the rev range; short headers for peak power, long for better low end torque. Tuning for peak power is better for track cars with close gears but for a street car with wider spaced gears to cover the greater speed range available then some mid range is desirable due to the increased rev drop involved in upshifts. Unequal length headers have the effect of tuning different pairs of cylinders for different parts of the rev range giving a better spread of power and torque. The stock weight flywheel works well at damping out the differences in torque pulses due to the unequal length headers.

For a street car I personaly would go with a supercharger on a stock or low compresion engine with an intercooler or charge cooler since for big speeds it's the torque spread and hence amount of power throughout the rev range that allows the car to pull the big gears needed for high speeds, and superchargers provide lots of torque everywhere.

chengteik

Cool, thanks guys. Seeing my mechanic today as he will be done tearing the engine apart. I'll see what exactly needs to be replaced during the rebuild then decide on how much budget I have left for mods. Will keep you posted.

chengteik

OK. Finally got my car back with her new heart!! We did a top and bottom end rebuild changing almost all parts less the crankshaft, engine casing, valves, pistons and cylinders. Also changed the cams to Schrick Porsche Motorsports spec cams. I believe that these are the same cams used on the 993RS. The engine runs really well now but I'm still breaking it in so have not gone past 4000rpms yet.

Only one problem that we can't seem to figure out. The revs drop too low when clutch is disengaged suddenly. I'll start another thread to discuss this problem.

pzull

Chengteik, did you switch to lightened flywheel? If so you would need reprogramming of engine management to take care of this. Otherwise I think read a mechanical fix for this somewhere on this board some time ago....or maybe I was imagining things.

So what were the exact mods you finally went with?

Hey Rob, How r'ya? I sold my 964 and bought an NSX at my new home country. 1st mods are suspension and entire exhaust system - same design as on my 964....but....this is being done at a manufacturing plant...pretty amazing - they "scanned" my car and existing exhaust system and are drawing my design on an autocad system which will then drive some automated laser cutters to fabricate the parts and then TIG weld the whole thing together...but the proof's in the pudding....still waiting to see the product. SHould be OK since they OEM for some of the well known brands around the world. There's so much more space on the NSX that I can almost optimise pipe sizes and lengths

nine64

[/QUOTE]
There's so much more space on the NSX that I can almost optimise pipe sizes and lengths[/QUOTE]

pzull did you go with wheel? BTW i sold my car today... so sad

chengteik

Nope, NO lightened flywheel. So I think it's mechanical. Checked for the obvious other causes mentioned in previous threads like engine oil overflow onto the ISV and airflow sensor but did not help. CAN'T SEEM TO FIGURE IT OUT! Started a thread to find help:

https://rennlist.com/forums/964-forum/191754-help-please-revs-drop-too-low-when-clutch-disengaged.html

Final mods were limited because of budget and cost of #1 below. Here's the list:

1. Brand new engine. Everything changed except crankshaft, engine casing, valves, pistons and cylinders.

2. Schrick Porsche Motorsports spec cams. Same spec as 993RS.

3. Equal length 29" headers. Still waiting on TRG quote as they just moved and are pretty busy but I'm definitely getting this in the next month or so. Exhaust setup will be similar to Pzull's.

Previous mods:

1. 993 6spd (full 993 4WD system)
2. RUF brakes
3. RUF Suspension
4. RUF 17" wheels (wish I had the 18")

PZULL, can you send me contact info of guy that does the 0bit piggy-back MAF system?

pzull

chengteik,
Product website: http://www.obitasia.com/ don't judge the product by their web design skills
Singapore dealer/installer : http://www.obitasia.com/singapore_dealer.htm
(use Bernard of BVO) He can get Sato the japanese tuner if you request.

Ask Andy (Flatsix) if he still has the 993 MAF part, if not Bernard uses a BMW part. You should do the tuning after running in engine and after you have all the mods in ie. exhaust, cams, etc. He has done a 964 in Tawan and based on increase in top speed it looks like you can achieve near 300bhp (not verified)

Are you going to cut the left bumper for twin exhaust or buy the ready cut gemballa version? not cheap.

Nine64,
You sold your car? Good Price I hope. Spoke the guy about the wheels but asked him o find out about the Work Emotion CR wheels - really light stuff - lighter than TE37s. ACtually these wheels would look great on a 964....and light...wonder why no ones done it.

2pc Work S1 :

Harold

Would definitely agree with Pzull, but would even go one further to suggest that the gains you may notice versus the potential problems may just not be worth it. The car you have already pulls much better with the 993 box in place.... I remember driving it some years back and felt it was one of the strongest 964s around at that time.

Harold

It was these sort of problems that had me remove all the mods that I had done on my 964 back to standard.... for a car that needed at the time to be a daily driver, these issues were just unacceptable for me. Sorry but I am really not into mods after my 964 experience. My 993 was left totally standard except for suspension and rims and I can say it was the singular most wonderful experience having a car that worked like clockwork under all conditions, day in day out.

pzull

Harold! 348?? heard u sold the best example of a 993 ('cept the driver) in the country, for a good sum.
How many hours in a month does the F-car work?
When u coming up to visit man? Track day on april 10th.

chengteik

Thanks Dennis. Will give them a call before deciding. This is my daily driver so need it to be reliable like hrold mentioned. Anyway this mod is still a few months away as still waiting for exhaust and complete breakin of new engine.

For twin exhaust, I'm goining to try cutting the left bumper first. If it looks ugly than I'll buy the Gemballa part (hopefully used).

Dennis, do you know of anyone who has used this MAF setup? And their experience with it?

pzull

Know only of Taiwanese 964 customer of Bernard although he has done many other type of cars in Singapore. But Andy has customer that has customer that has done autronic which is more complicated and expensive. Ask Bernard if he has money back guarantee.