Nikki running insanely rich
12-07-16, 07:10 AM
#52
carb whisperer
I tried different sizes with mine until I figured out that the first size I went with pulled the hardest from low to mid range. It's perfect for powering out of twisty turns...
12-07-16, 10:03 AM
#53
Waffles - hmmm good
iTrader: (1)
How about this for a comparison. My buddy has a ported reni in his rx8
(done by Petit down in FL). A very reputable shop and his engine runs great.
So its got some extra oomph in it beyond a normal rx8.
He can barely beat my stock port 12A with the hogged out nikki when we play around
entering the highway following each other on the entrance ramps going to C&C or other
meets. When I say barely, I mean he very slowly gains on me so that he's only gained a
few feet, when we get to the end of the ramp (very long ramp btw). It flat out
frustrates him that he has this ported reni in his rx8 and it can barely beat my little 12A.
My nikki venturis were hand done by me using a dremel and I have no measurements of
the angle or width but it sure made a difference. I'm running 105 jets in the primary
and I think 120ish in the secondaries at this point. The idle and cruise mixtures appear to
be good (based on plug color) and the secondaries (manual) when opened up feel like I
have a turbo in it. It will slam you back in the seat.
It beats the hell out of the RB Dellorto 48 I ran for years. Never going back!
(done by Petit down in FL). A very reputable shop and his engine runs great.
So its got some extra oomph in it beyond a normal rx8.
He can barely beat my stock port 12A with the hogged out nikki when we play around
entering the highway following each other on the entrance ramps going to C&C or other
meets. When I say barely, I mean he very slowly gains on me so that he's only gained a
few feet, when we get to the end of the ramp (very long ramp btw). It flat out
frustrates him that he has this ported reni in his rx8 and it can barely beat my little 12A.
My nikki venturis were hand done by me using a dremel and I have no measurements of
the angle or width but it sure made a difference. I'm running 105 jets in the primary
and I think 120ish in the secondaries at this point. The idle and cruise mixtures appear to
be good (based on plug color) and the secondaries (manual) when opened up feel like I
have a turbo in it. It will slam you back in the seat.
It beats the hell out of the RB Dellorto 48 I ran for years. Never going back!
12-07-16, 11:14 AM
#54
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"Ditto" Thanks Jeff20b.
I also have an 85 GSL stockported that I just upgraded to DLIDFIS and am now hogging out a spare Nikki. 24 MMS primaries. I am following your specs to a T. I love the DLIDFIS ,but the PO screwed up the existing Nikki. Mid range sucks. I will investigate it later
12-13-16, 09:15 AM
#55
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Jeff, I've been following your evolution with the Nikki carbs and I'm hoping you'll provide some clarification as to your current position. I have a 1984 GSL that I've owned since it had 5000 miles on it. I did replace the engine at about 155K (although I learned later that I didn't need to do so and still have it). I have about 188K on it now and I don't drive it a lot any more. It remains a beautiful car in mostly stock condition (front & rear neoprene bushings, RB middle pipe, RB racing springs) with the 5 speed, leather, and moon roof. It's running a bit rough without a lot of power right now and it's never been very peppy. I did tie off the 2ndary to make it mechanical, but that hasn't helped. I'm about to replace the cap, rotor, wires, and plugs as it's been about 35K since I did so. I recently replaced the fuel filter and the electric fuel pump is about 50K old.
Back to the Nikki, I've been loathe to remove all of the emissions and anti-backfire valves (as that older write-up from someone else suggested be done), and I've never hogged out venturis before so, I'm afraid of taking that pretty radical step. On the other hand, your suggestions about air bleeds and fuel jets sound like they could be really beneficial. You haven't been entirely clear on whether your suggested mods require hogging out the venturis, although it's clear that they work for both NA and boost. I'm not boosting mine, but would like to improve power.
Your original suggestions were for the following:
Primary side - 120 primary main fuel jet drilled to 118, 70 on the primary main air bleeds, and take the nickel-plated 60s from the 2ndary side-drill to 0.45" and swap to primary side, leaving long slow air bleeds alone.
Secondary side - 150 2ndary fuel jets, mode 2ndary main air bleeds to accept 118 jets or 0.45 air bleeds, fill brass primary slow air bleed with solder and swap into 2ndary holes, fill long 2ndary slow bleeds with solder.
Recently you wrote -
[I]idle air bleeds: 118 to 124
transition bleeds: 46 (stock)
primary main air bleeds: 70 (stock)
secondary main air bleeds: 80
secondary transition bleeds: solder filled upper tube only. Leave lower holes open.
nickel plated anti-siphon bleeds: 60 (stock)
That is my boost and NA air bleed tune which is universal.
Fuel jets depend on the size of your venturis and what your wideband tells you.
You did mention for the earlier stuff that it was for a 24mm venturi, which is clearly not stock.
Another thing, the accelerator pump recommendation was for the stacked gaskets (6 total) and an extension on the pump rod. Do you still recommend that? BTW, I have the hygrade kit from Rock Auto you recommended. I will say that I rebuilt the carb a long time ago and that wasn't successful. I took it to a guy in Cary, NC who was supposed to be an expert on the carbs. He rebuilt it, but struggled with it flooding (also replaced the shutter/coasting valve combo - don't know if I needed it), but finally got it working. It's been 20K or so since then. I tested the shutter solenoid according to the factory manual, and the coasting valve with a vacuum pumpl...both fine. I did so because the sound from the engine was as if it was starving....sort of a whirring/buzzing/fluttering sound.
Okay, enough blah, blah, blah, blah :-). Any advice or suggestions you might make are welcome.
Back to the Nikki, I've been loathe to remove all of the emissions and anti-backfire valves (as that older write-up from someone else suggested be done), and I've never hogged out venturis before so, I'm afraid of taking that pretty radical step. On the other hand, your suggestions about air bleeds and fuel jets sound like they could be really beneficial. You haven't been entirely clear on whether your suggested mods require hogging out the venturis, although it's clear that they work for both NA and boost. I'm not boosting mine, but would like to improve power.
Your original suggestions were for the following:
Primary side - 120 primary main fuel jet drilled to 118, 70 on the primary main air bleeds, and take the nickel-plated 60s from the 2ndary side-drill to 0.45" and swap to primary side, leaving long slow air bleeds alone.
Secondary side - 150 2ndary fuel jets, mode 2ndary main air bleeds to accept 118 jets or 0.45 air bleeds, fill brass primary slow air bleed with solder and swap into 2ndary holes, fill long 2ndary slow bleeds with solder.
Recently you wrote -
[I]idle air bleeds: 118 to 124
transition bleeds: 46 (stock)
primary main air bleeds: 70 (stock)
secondary main air bleeds: 80
secondary transition bleeds: solder filled upper tube only. Leave lower holes open.
nickel plated anti-siphon bleeds: 60 (stock)
That is my boost and NA air bleed tune which is universal.
Fuel jets depend on the size of your venturis and what your wideband tells you.
You did mention for the earlier stuff that it was for a 24mm venturi, which is clearly not stock.
Another thing, the accelerator pump recommendation was for the stacked gaskets (6 total) and an extension on the pump rod. Do you still recommend that? BTW, I have the hygrade kit from Rock Auto you recommended. I will say that I rebuilt the carb a long time ago and that wasn't successful. I took it to a guy in Cary, NC who was supposed to be an expert on the carbs. He rebuilt it, but struggled with it flooding (also replaced the shutter/coasting valve combo - don't know if I needed it), but finally got it working. It's been 20K or so since then. I tested the shutter solenoid according to the factory manual, and the coasting valve with a vacuum pumpl...both fine. I did so because the sound from the engine was as if it was starving....sort of a whirring/buzzing/fluttering sound.
Okay, enough blah, blah, blah, blah :-). Any advice or suggestions you might make are welcome.
12-13-16, 02:14 PM
#56
idle air bleeds: 118 to 124
transition bleeds: 46 (stock)
primary main air bleeds: 70 (stock)
secondary main air bleeds: 80
secondary transition bleeds: solder filled upper tube only. Leave lower holes open.
nickel plated anti-siphon bleeds: 60 (stock)
transition bleeds: 46 (stock)
primary main air bleeds: 70 (stock)
secondary main air bleeds: 80
secondary transition bleeds: solder filled upper tube only. Leave lower holes open.
nickel plated anti-siphon bleeds: 60 (stock)
Yes, the accel pump mod is recommended as 6 gaskets and extension piece. Also be sure to pay attention to the nozzle and only enlarge it if you need more fuel. I do .90mm to 1.18mm depending on what the carb will be used for. Otherwise leave it stock .40mm (though I think that is tiny and you might try for .60mm at first).
Your goal is to have mechanical secondaries that do not bog when you open them below 4000 RPM. I can open mine at 2000 RPM but don't expect much power down there. At least it won't bog, unlike if you leave your secondary air bleeds stock. Then expect to have to wait until at least 3800 bare minimum as that was my finding before the air bleeds were figured out. And we're talking NA here. Boost would always have an annoying delay regardless of the RPM at which they were opened until the 80 mains and solder filled long slows (upper section only) were figured out.
When you say shutter solenoid and coasting valve, I am not very familiar with the stock parts of a Nikki emissions system as I began my rotary experience on old school and then moved to 1st gens when they didn't have to pass emissions anymore in most areas. Thus I am not familiar with any of it. You would need a CA resident to help you there. But what I can tell you is none of it is needed for a good running setup that is better than stock if you follow my air bleed advice. Remember the stock air bleeds in the carb were meant for all of the rest of the system and were designed to work together. But the system is very complicated and when one part of it is no longer quite up to par, the rest of the system can suffer, as yours is.
Your car would vastly improve in every way if you follow our advice on things like going direct fire, hogging out the Nikki intelligently, improving the intake manifold, going long primary exhaust, swapping to a light steel flywheel while keeping a stock duty disc and pressure plate in there, and so on.
12-14-16, 09:07 AM
#57
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Hate to sound dumb, but are the transition bleeds the slow air bleeds?
Are the idle air bleeds the same as the richer air bleeds?
In the 84-85 Nikki, they added a #2 main air bleed in the curved tube over the idle compensator valve on the air horn. It seems clear that this is not the same as the primary air bleeds. Should this be plugged or enlarged or left untouched....if you know?
Also, it would be great if you could clarify (via pictures perhaps or even video) how to actually hog out the venturis. I need to get a 2nd Nikki carb to play with from somewhere. I'll check around in NC with folks who might have one. There's a guy out in Eden who has a dozen gen 1s on his farm (bought a Chevy 2500 from him). Another guy in Cary has some as well.
Oh, and THANKS!!!
Are the idle air bleeds the same as the richer air bleeds?
In the 84-85 Nikki, they added a #2 main air bleed in the curved tube over the idle compensator valve on the air horn. It seems clear that this is not the same as the primary air bleeds. Should this be plugged or enlarged or left untouched....if you know?
Also, it would be great if you could clarify (via pictures perhaps or even video) how to actually hog out the venturis. I need to get a 2nd Nikki carb to play with from somewhere. I'll check around in NC with folks who might have one. There's a guy out in Eden who has a dozen gen 1s on his farm (bought a Chevy 2500 from him). Another guy in Cary has some as well.
Oh, and THANKS!!!
Last edited by ericdash; 12-14-16 at 09:11 AM.