Me again.
> My $.02 worth.
No one's opinion here is worth a measly $.02. It's amazing the amount you
guys know about these little beasties. I would have lost the courage to work
on my 6 a long time ago if it were not for the lifetimes (I can say
lifetimes; I'm only 29 years old ;-) ) of experience you provide on this
list! Too bad I didn't get a photo of me in my dining room, draped in my
car's wiring harness last winter...
> A TR6 engine with 10:1 and an S2 cam is hardly stock.
> That being said, I offer two pieces of advice:
>
> 1. dump the Weber downdrafts. If you're absolutely stuck on them, that's
> okay with me. My personal opinion is that those things can't flow very
> well. On the other hand, I'd love to see some dyno numbers with them.
The DGV's were on the car when we bought it. After spending many diligent
hours at work searching the archives and every other page I could find on
carbs for a tr6, I find the general consensus to be that the dual Weber
DGV's isn't the best choice for an autocross/street car. The "toilet trap"
adapter isn't ideal in terms of airflow. All carbs are tricky to tune right,
so I can't use that as an argument. Personally, I think every car is a
little different in what folks expect out of them. You get what works best
for your situation (finances included).
We have a Clayton chassis dyno. My husband got it for free at his last job
when the company couldn't see the value in keeping it. It has not been used
in a long time. Once we get it operating and learn enough VB to make a
data-aquisitioning program for it, we'll get the car on it and see what
happens. Chalk up another winter project for us.
> If you decide to change the downdrafts, the stock Z.S. 175's are okay and
> you could also use SU HS6's. If you read the comp. prep book, they were
> able to get pretty good numbers with the stock carbs. I believe the key
> to getting powere from the Z.S.'s or SU's is in needle selection. In that
> regard, needles are somewhat easier to change on the SU's - but you can
> make the SU needles fit the Z.S.'s (as described in the comp. prep manual.
We've been thinking of getting Richard Good's tri-stromberg manifold. The
car came with two lumps of oil and dirt which turned out to be the original
ZS's. The ZS's offer a port for vacuum, which we don't have on the DGV's. I
think Good's setup will give us the best results. It gives the engine more
air than the DGV's do. It also has an impressive "kewl-factor" (something
anyone with a Mimosa TR6 would want; why else would they drive a Mimosa
TR6?!?)!
The triple Webers seem to be better suited for high-end performance. We want
our car to remain somewhat streetable and it is out of our budget.
I'm guessing that the ZS's are not as easy to work with compared to SU's
because the designers didn't want folks tinkering with the carbs and messing
up the emissions. However, they are not impossible to work with; I've heard
enough people say so. Since getting one ZS is more affordable than SU's,
that's the route we're looking at.
Questions:
Can you tune a pair of SU's to perform the same as three Z-S's?
Will two SU's flow the same (at least usable amount of flow) as three Z-S's?
What is the CFM (cubic feet per minute) flow rating on the SU and Z-S of
comparable size?
Were there any variations of the SU HS6's made during production or were
they all exactly the same?
> 2. distributor. You can do several things.
>
> Get the distributor to a competent automotive shop with a distributor
> machine. Get them to curve the thing for full advance at 2500-3000 RPM's
> You're running pretty high compression ratio at 10:1, so don't go too
> crazy on the advance thing. The comp. prep book lists 23 degrees total
> advance for cranked-up TR6 engines.
>
> Do this for mechanical advance only and dump the vaccuum retard
> altogther. If you "yank the can" from the dizzy, don't forget to fill the
> resultant hole in the case. Unless you only drive on dry days and never
> go on any dusty roads... in other words, if your car is a "garage queen"
> you don't need to fill the hole. If you need me to explain why - I may
> suggest that you take up other persuits than working on your TR6. ;-)
I may not know a lot about cars yet, but I know what dirt can do to a car,
and what a #@&$ it is to get it out. I've still got 10 year-old Nelson
Ledges mud packed in the fenders. I don't like thinking what it would do
inside my motor...
Also, my car is NOT a queen. It may act like one when it doesn't want to run
right, but I'm proud to say each year we own it, it gets more miles on it
than the previous year. Besides, I've always heard the sixes referred to as
"hairy-chested". A hairy-chested queen? Brrr, I'll pass! A hairy-chested
prince, OTOH...
> _But_, the problem with that setup (the recurving of the stock dizzy) is
> that if the curve that you come up with doesn't work with your carb/cam
> setup - you're stuck having to recurve (again) to get things to work
> right. This is not optimal and possibly expensive if you have to do it
> many times.
Since we have a dizzy that works, I think we'll look into getting that to do
what we want first. Has anyone tried changing the springs inside at home?
Would that buy me anything?
> So - if you get a Mallory dual point dizzy, you can change the total
> advance by tweaking a screw in the housing to add/remove total advance.
> Thus, if you were tuning for max. power, you could probably set the thing
> once in a one hour dyno session.
Where can you get a Mallory distributor for a TR6, or at least get
information on them?
> If you are totally insane, you could go to a crank-trigger setup...
I married a car guy. Then what did I do? I got involved with cars myself
(Ew, I gotta touch that?!). Did I get a car that I fit well in? Noooo, I had
to get one that I have to remove a windshield wiper just so I can see what's
in front of me when autocrossing. I'm crazy enough, thank you very much!
Again, thanks to everyone who's been helping me out!
Wendy Hart
1975 TR6 (SCCA FSP/street) (My Hairy-Chested Prince?)
1976 TR7 (future SCCA IT car?)
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