steve91tt

I’m not sure which sanctioning bodies allow strut tower braces. I know that the NASA and SCCA rules are readily available on the web. I suggest that you make a list of who you specifically want to run with and google the rules. Maybe someone with more experience than me will chime in but as I understand it, it's important to not just tie the strut towers together in the front but to triangulate them to the firewall and/or cage. The nose of these cars tend to bend at the firewall, especially if spring rates exceed 250 or so in the front. If you don't deal with the floppy nose the car itself becomes an undampened spring. Also, don't just throw steel at it. Figure out the week spots and reinforce as little as you need to. Weight is your enemy even if you have +400HP. The more it weighs the harder it is to stop, change direction and accelerate. You will also consume more tires, brake pads and fuel.

Assuming that the style of competition racing are you considering includes going around corners... There are specific rules for each class regarding roll cage / body reinforcement. If the rules in your specific race class allow the cage to tie in both the front and rear strut towers then you can increase the chassis stiffness substantially. If you can't extend the cage past the firewall then generally the floppiness of the nose on these cars is your limiting factor. You need to reinforce the chassis so that forces can move efficiently corner to corner across the car as much as the rules allow while minimizing weight. If you decide to go the frame rail route. Bad Dog frame rails are very well made and an excellent value. I have a set in my garage that are going on my track car next weekend.

The BHJ part also has a stepped ID. This makes installation much easier on a press fit part such as this.

I ended up going with the BHJ damper (Part #: NIS-REB-6-SP). It appears to be a very well made part and installed without any fuss. However, I did widen the mouth of the inner end of the keyway slightly as per Dave Rebello's suggestion. This allows for easier alignment while installing. I raced the car this past weekend and the damper seems to be doing its job. I wish I could say the same for my ignition coil...but that's another story.

That's one of the things I like about the bhj damper. It has an optional bolt on electronic ignition ring and sensor mount for the datsun motor. I'm sticking to my Mikuni's and distributor for now but it's nice to have an easy upgrade path for the future.

I don't doubt that the euro dampers can take a beating but the euro units that are out there are getting old so if I went that way I'd want to have it rebuilt before I used it. I don't have time to start down that path as I have 4 vintage car races to run in the next 2 weeks.

The BHJ unit cost me $385.

After spending some time on HybidZ and speaking to Dave Rebello I've come to the conclusion that ATI and BHJ dynamics make the best dampers for my application. Dave uses the ATI units on the engines he builds and he says that he has never had one fail. I decided to go with the NIS-REB-6-SP from BHJ. Dave recommended this model for a L30 or L32 stroker such as mine. He recommends NIS-REB-6 for a higher rev'ing application.

Does anyone know if the stock damper or the Euro damper mentioned above fails safe? One good thing about the Powerforce damper and the BHJ/Rebello unit is that when the rubber fails the inner and outer rings stay together. If this was not the case, and it failed on the track I suspect it would have gone through my rad or worse. I am hesitant to install a damper that would fly apart if the rubber fails.

To be fair, my car spends most of its life between 5000-7000 RPM. I have the same damper on my street car and I'm guessing it will last a good long time. So I guess I'm guilty of buying two of these as well. Does anyone have a suggestion for a damper that will handle high RPM's for extended periods of time?

It was the Powerforce SFI-Spec Racing Damper from MSA. http://www.thezstore.com/page/TZS/PROD/10-2138 I had a local machine shop measure my crank and hone the damper for a proper interference fit before installation.

My harmonic damper decided to come apart on my track car last night. It was only 54 weeks old (52 week warranty). It used to look like this... "The manufacturer reported safe rev limit with this Damper is 10000 rpms" I'm hoping the engine was not damaged. Time will tell. Any recommendations for a new damper? I'm leaning towards this one... http://www.bhjdynamics.com/index.php?main_page=product_info&cPath=10&products_id=241&zenid=0usn3hloiia3ff5sr1himig8n6

Very cool idea. How will you adapt the manifold? Will you start with an SU manifold and start TIG'ing? Should be a fun build. Looking forward to following your progress.

You might also consider running a low oil pressure alarm on the track. I use one of these... http://www.longacreracing.com/catalog/item.asp?id=785&catid=11 I substituted an 85dB siren for the light. If the oil pressure drops below 20psi on the track the alarm will sound. If I don't turn on my Accusump while on the track I get an alarm at every braking zone and hard corner. The alarm is the best $25 insurance policy I have ever purchased. https://www.cantonracingproducts.com/product/24-026/24-026----ACCUSUMP-2QT-NO-VALVE/ If you are going to road race an L6 I would think about an upgraded baffled pan or an Accusump. If you don't already have one. Just my $0.02.

I also use VR1 and change it every 10 hours of track time.

I drove the illuminas with progressive Eibach springs in my 1973 for a while. I may have a sensitive spine but I found them a little harsh for my liking for the street so I swapped them to my track car. The harshness may have been due to a mismatch of the springs and the valving in the struts but I didn't like the ride quality regardless of the setting. I'm currently running KYB's. The Illuminas, in the track car, with linear springs (250/225 sectioned coilovers) are hitting the bump stops too often. Unfortunately you can't increase the spring rate much more than what I have with the Illuminas so I plan to swap them out for a set of Bilstein's once John gets the engineering done. http://forums.hybridz.org/topic/104325-bilstein-36-and-46mm-piston-shocks/page-2

I'm using a cheap parts store pump. I've never had any issues with overheating so I didn't upgrade the pump. My stock 1973 street car has always run hotter than my rebello powered track car.

Good thought Blue but there is only one sensor in the thermostat housing and it does not contact the thermostat regardless of how I clock it.

The car runs great. No issues. I would not have noticed the thermostat if I hadn't have removed the top rad hose and looked down the pipe into the thermostat housing. I will try to get my hands on a pressure tester and do some more investigation.

Thanks blue. What's the best way to do that sort of test? Check for bubbles?

The thermostat opens as it should around 160°F in a pot of water. I have always tried to keep the RPMs down until the car is fully warmed up but I can't say for sure that I have done so 100% of the time.

I took apart my thermostat housing to find this... The thermostat was bent and pushed up off of the seat. The car has been running fine and has never shown any signs of overheating. This is a track car in which I am running a Rebello L30 with blocked heater circuit, aluminium 3 core rad and a 20psi cap. Has anyone ever seen this sort of thing before? I don't want to just throw a new thermostat in there if this is a symptom of something else being wrong with the cooling system. Thanks

Thanks for the link. I'll be there on Saturday for qualifying.

I'm running a set of 44's with AFM. I'd be happy to help out.

Agreed, when I was running the RX7 pump in my Mikuni powered L30 track car I did not see any adverse effects of the undersized pump other than very low fuel pressure until I changed to 37mm chokes. When I moved up to the bigger chokes I started going lean at WOT near red line in 4th so I switched to a bigger pump and solved the problem. I can see no downside to the occasional 0psi reading on the fuel pressure gauge as long as AFR's don't go lean. If fuel supply is an issue the lean spot will generally occur after long periods of sustained WOT operation I don't see this being an issue with a street car unless the fuel system is badly undersized. Just my $0.02.