This is about my 260z which I have just fitted triple mikuni's to. It has a bog stock l26. So I have fitted tiny little 30mm chokes, but I also have a set of 34mm chokes.
One set is to small for this engine and the other set is to big. (Stock as a rock l26)
What would be better? To big or to small? And how would the larger chokes act compared to the smaller?

Mick

If it helps I run 32mm chokes in my worked l18 (45 webers on a road car). For a std engine I would go the smaller ones as they will give you better driveability and you shouldn't notice much if any loss of top end speed, but in saying that the 34mm ones wont be too big and will give you more power at high revs ( >5000) but you will notice down low. Make sure you have the correct jets and emulsion tubes.

_________________
Chris Thomas

1971 1600, mild L18, 5 speed

All I want is less to do, more time to do it and higher pay for not getting it done.

which mikuni carbs do you have? what size are they and what jets etc? Personally i think the 34 chokes would be perfect if carbs are jetted to suit

Sorry. Those are some important factors they are 40mm and I not sure on the type, but r type rings a bell

if they are the std Toyota carbs that came out on the 18R 2TG motors then i think std jetting is as per chart attached. who knows what jetting might actually be though unless you pull them apart and check? you could just run the 30mm chokes and the 34mm chokes and see what feels best.

should mention im no egg spert when it comes to tuning carbs and the chart is plucked from the net so cant prove its accuracy. however with all the resources i have come accross the figures are very similar. ive been reasearching mikuni stuff as im hoping to run a pair of 44mm carbs on my 510. Wolf creek racing can supply parts and jets and there website is also worth checking out. just for the record ive worked out that the factory PHH40 setup as per the chart i posted up is a very good Basline for a stock L20B.

The last engine these carbs were on was an l28 built by Peter McDonald and made 245 rwhp so I think the jets may be to much for a standard engine. I will pull them out when I have some time and have a look. I will also post up a photo of the carbs a little bit late so you can see what I am talking about.

Did you get this info from Peter Mac himself, or third hand.
Doubtfull you'd get 245 wheel hp from 40's.

Running a stocko L26 i'd suggest running the 30 mm chokes, as, you will get much better airflow speed, which gives higher fuel atomisation, and will have the engine running a lot smoother.
It wont rev past 6000 rpm, but being a stocko, you dont need to go past there.

If the jetting is original ex Toyota 2TG, the cylinder volume is almost the same as a L26. That worked fine on the 2TG, run that!
It may need a size up/down on the Air corrects, or Fuel Mains.

Later on, you could consider having the chokes machined on a lathe, from 30 to 32mm, but try to give them a bit of fore and aft taper to match old shape.

The 34mm chokes, will in the 40's on a stock L26 cause the engine to stumble and falter, this will be due to fuel "dropping out" of the airflow, due to lack of airflow speed.

I have been using twins/triples Miks and Webs in sizes up to 50 and 55 mm for some years, getting them sorted is a pain, but once done right, they sing.

_________________
Yep, i race a Datsun, and I drive a truck, sometimes I get confused, and then the truck goes fast, and the Datsun gets a lot of boxes shoved into it. AWW GEE

Oh, and those trumpets are way too short, 50 mm long, at minimum, use taller K&N type dilters over them. Dont use the six individual sock types

_________________
Yep, i race a Datsun, and I drive a truck, sometimes I get confused, and then the truck goes fast, and the Datsun gets a lot of boxes shoved into it. AWW GEE

Sorry that was 245ish hp on the engine duyno not at the wheels. My bad.
I have learned that the main jet and the ari jet are to small, so there for it is running rich
I hope replacing these with the standard factory jets will fix the popping out of the carbs.
I have some coming next week. I am aware the trumpets and the manifold are to short. I will change these when I can.
I will probably make my own air box for them. I might put a Perspex lid on it so I can still see the trumpets.