85Gen1

hey all is anyone using MSD boost/timing box to retard their timing under boost I'm having problems with my 7 at wide open and I have narrowed it down to having too much advance but I cannot get the car to idle without advance. any advice or help would be appreciated thanks all.

Rotospeed

iTrader: (8)

I have not, but may be able to help.

What are you running for timing and boost

85Gen1

well currently for timing the only way I could get the car to idle and drive down the road in primary's was full advance locked. I've tried to play with different degrees but none have been successful other than that. right now the car is running 15psi. it holds boost and pulls fine in primary's but once u get into the secondaries it starts to sputter and fall in its face. AFR at WOT is 11.2 so that leads me to believe it has plenty of fuel I've been told it should be fairly retarted in full boost but I wasn't sure how people were doing it.

Rotospeed

iTrader: (8)

A lot of people lock the dizzy and set the timing @10 deg. that should be good
to for 10-12 psi.

Rule of thumb is retard it 1deg. for 1psi.

Stock timing@full advance is 20 our 22 iirc so for 10 psi you retard the timing back to 10deg.

your running 15 psi so that would put you@ 5 deg with a locked dizzy..i recommend setting boost and timing@10 once that's working good then up the boost if you want

Fwiw when I was running blowthrough I did not like the locked dizzy most people run I'll add info on that tommarow when I'm not using my phone

Rotospeed

iTrader: (8)

What carb are you using? After re reading your post...your secondary jets are way off.

What do the afrs do when you stomp on the gas? Do they go to 10 our 17

85Gen1

carb is the Nikki that came on the car and I had it sent out to be prepped.when I stomp it my Afr will go to about 10.6 then pick up to 11.2

85Gen1

rotary shack did the blow through carb setup. I went through and it does have the necessary things for a blow through carb including mechanical secondaries

Rotospeed

iTrader: (8)

sounds like your secondarys are too rich and its flooding out when you step on it. so your dizzy is locked.... but what is your timming set at?

85Gen1

as the car sits its locked at 19degrees advance. that's the only way we could get an idle from the car. primary jets are 91 and the secondaries are 135s

Rotospeed

iTrader: (8)

Some thing is wrong if it won't idle with less than 19 deg. We need more info, what exactly is your set up? How is the dizzy locked what turbo do you have? Post pics of the engine bay. After you get this info bad83 our some one with more nikki experience can help more with jet sizes ( I used holleys)

Do you have a dizzy thats not locked?

85Gen1

here's a rundown of the engine mods in gonna leave out suspension and interior due to its irreverence in the problem.

Godspeed tdo5 16g
custom manifold
custom downpipe
msd 6a
blow through Nikki carb prepped by rotaryshack
cxracing intercooler DIY kit
walboro 255 fuel pump
innovate LC1 wideband
glow shift boost gauge , oil pressure, water temp
Mallory boost refrence fuel regulator
aluminum turbo bonnet
. off the top of my head that what I rember I'm my build thread in my sig is a complete list but that should be what u need. an engine picture is in the build thread.
as to the lock dizzy the way I have it is the two vacumn canisters are plugged and it is locked into position through the dizzy bolt on the block

Rotospeed

iTrader: (8)

Starting the thread with that info makes it a lot easier for us to help you


You have a nikki carb on a RB manifold..... That may be causing some problems for you. Your dizzy is not locked if that's all that's done to it.

This it's what I did when I was running blowthrough and out worked verry well;

A. Connect your brake booster to manifold vac. use a pcv valve in line so the booster gets vac. But not boost.

B. Connect a vac. line from a port on the intake to the dash pots on the dizzy.

C.with the car ideling (around 1k ) turn the dizzy to set the timing at 10 deg and adjust the carb / idle so it's happy if your car won't idle that low set the timing at 20-22 deg with the rpm about 3800 rpm so the dizzy is fully advanced, then adjust the carb/ idle

the vac line must be connected to manifold vac NOT the nipple it was connected to stock

you now have working brakes and boost retard of 10 deg.


Fwiw I think 17 psi is making a lot of hot air on that turbo 10-12 is a lot safer. And ask the q's you have been asking in the single turbo section would be better asked in the 1st gen section

85Gen1

awesome. I'll give that a try thanks for your help. finally an answer I can use