[F-BIRD'88]

Watch the blower case temperature when dyno testing @ WOT under boost.
If it gets hot after a few pulls , stop and let it cool down. thats what the water/methanol injection is for.
dead cold blower case ='s backfires and fuel wash and fouled plugs poor idle . too hot blower case ='s risk of detonation under boost.

02 sensors can give false readings ( exhaust leaks, blower pass thru ( too much cam overlap overscaveging) ignition misfire)

ALL 8 plugs appearance and exhaust temps and trumps AFR/02sensor readings

Test with power valves plugged (remove and plug) and big primary jetting +6 to +10 jets sized up. untill you can get the carbs boost referenced. Thats the best you can do with those 1850carbs.

[mustang 671]

hi guys.

i spoke with the ecu guys today @ omex and also spoke to the dyno guys.

they are going to change the way the ecu reads first. so instead of the "tps" sensor it will read from the "map" sensor and also they can set the ecu to change as the map sensor reads boost ,

i am going to set my timing up from what you have advised and run it on sunday and let you know how i get on, i am so busy with work so i dont expect i will get to the dyno shop next week. i think it will be the week after.

thanks for the carb advise. that helps with the sec plate as i would like to be able to jet it like a metering plate .

will do a vac test this weekend from under the carb and above the blower and let you know.

so from what you have all said it seems blown motors like mine rarely used chokes . so the choke flabs are to be fixed open always ?

i can get 98 octane fuel

when do you recoomend to get my water meth inj up and running ? its injected in the inlet manifold ( t bird ) will this still be beneficial for the blower heat ? understand it will help reduce detonation , its set to come in from 4psi and spray more water meth mix as the bost builds .

also i have a spring load toggle switch which over rides the system and allows me to pump as much water meth i want into the inlet - when would be a good time to use this ? i thought if i was going to do a santa pod run ? or when i am in traffic and the weather temp is hot hot ?

ok so 2-3 pumps of throttle ( cold ) and catch it and hold @ 2000 until it warms up. start up with 36 d btdc and its seems to want a pretty much flat timing curve with the ecu retarding the ign when boost comes in using t buirds figures for the amount of boost it shows.

any other advise on what figures to put into my ign table ? so ie @ 800 rpm and engine load 0 it will be around 36d btdc, but what about 800 rpm and engine load taken from tps sensors @ 50 % load and then @ 100% load. and etc etc for the rest of the rev range and rpm figures.,

i know it seems crazy to think that at 1000 odd rpm the engine load will be 100% but for that split secound when i floor it - it will probably be that

[cobalt327]

If you have an automatic transmission w/a torque converter, the stall speed will see to it that you won't be fully loaded when you floor it from 1000 rpm.

Remember its boost that you're concerned with. Boost will build quickly when the engine is loaded- but not instantaneously. While boost is non existent or still very low, the timing can be higher. You want this so the engine can spool up using the right amount of ignition lead until boost sets in, then the timing is taken away as boost increases.

It's better IMO to have a tunable secondary block than using a 4160 secondary plate drilled to accept jets. The link is just one such example.

4150 style carbs can be mounted sideways to clear the rear bowls. Takes a different mount and linkage obviously. Enderle linkage shown on member Blown Camaro's photo below:

[mustang 671]

thanks cobalt , yes i am going to get the side mounted linkeage and i already have a secoundary metering plate to use . looking forward to tomorrow , will let you all know how i get on . am going to put some ign figures into my ecu .

where can i get the side mounted linkage from ?

[mustang 671]

Edelbrock Tunnel RAM Linkage 2 x 4 Holley Rat Hot Street Rod Gasser | eBay


what your thoughts ? will it work ? my cousin is in california for a few weeks working . he already has some billet bonnet hindges for his freight suit case ( he works in the raf ) lucky for me

[F-BIRD'88]

Originally Posted by mustang 671

Edelbrock Tunnel RAM Linkage 2 x 4 Holley Rat Hot Street Rod Gasser | eBay


what your thoughts ? will it work ? my cousin is in california for a few weeks working . he already has some billet bonnet hindges for his freight suit case ( he works in the raf ) lucky for me

Get him to bring you back a pair of 750 holley blower carbs.

Re 600 carbs and sec metering plates: the plate once correctly tuning for your motor on the dyno will work just as well as a sec metering block.
no need to turn the carbs sidways. just get two metering plates and
modify for screw in holley jets (simple drill and tap threads) and dial them both, in on the dyno.
real simple.

The 750 blower specific carbs will get you very very close to max performance, out of the box. Any required tuning/jetting will be minor ...The EFi is going to be a big water of time and money.

Water meth injection is much more effective when injected above the blower.
When below the blower you would have to account for the rise in manifold pressure under boost and compensate in the injection pressure
same with the EFI. Boot referenced fuel pressure.

When the fuel and or water/meth is injected below the blower, the blower is not cooled by the fuel.
The air is not cooled (charge air intercooled) near as effectively. Two big reasons why:

The 750 blower carbs will do a whole lot better job on this motor , than EFI.
They will make more power too. Thats 3 big big reasons, for a fraction of the price.

if you're going to stick with the 600's and want to optiminze them they will work best if you cut the choke horn off, mod the body for boost referenced power valves and mod for swappable screw in air bleeds and optimize the primary metering blocks.
(idle feed restriction, (power valve channel restriction size)

I would not bother. just get the right 750 blower carbs. Those you can mount sideways.

[mustang 671]

Originally Posted by F-BIRD'88

Get him to bring you back a pair of 750 holley blower carbs.

Re 600 carbs and sec metering plates: the plate once correctly tuning for your motor on the dyno will work just as well as a sec metering block.
no need to turn the carbs sidways. just get two metering plates and
modify for screw in holley jets (simple drill and tap threads) and dial them both, in on the dyno.
real simple.

The 750 blower specific carbs will get you very very close to max performance, out of the box. Any required tuning/jetting will be minor ...The EFi is going to be a big water of time and money.

Water meth injection is much more effective when injected above the blower.
When below the blower you would have to account for the rise in manifold pressure under boost and compensate in the injection pressure
same with the EFI. Boot referenced fuel pressure.

When the fuel and or water/meth is injected below the blower, the blower is not cooled by the fuel.
The air is not cooled (charge air intercooled) near as effectively. Two big reasons why:

The 750 blower carbs will do a whole lot better job on this motor , than EFI.
They will make more power too. Thats 3 big big reasons, for a fraction of the price.

if you're going to stick with the 600's and want to optiminze them they will work best if you cut the choke horn off, mod the body for boost referenced power valves and mod for swappable screw in air bleeds and optimize the primary metering blocks.
(idle feed restriction, (power valve channel restriction size)

I would not bother. just get the right 750 blower carbs. Those you can mount sideways.

great , ok will tap the front secoundary metering plate to accept the jets . i do have a base plate below the carbs ( above the blower ) that have 2x allen key screws in the back ( facing the driver ) should be able to inject in there with water meth ?

[F-BIRD'88]

Originally Posted by mustang 671

great , ok will tap the front secoundary metering plate to accept the jets . i do have a base plate below the carbs ( above the blower ) that have 2x allen key screws in the back ( facing the driver ) should be able to inject in there with water meth ?

I would not mod the blower carb adapter base plate. I'd leave that as is...I would use two 4bbl carb spacer style water injection plates (looks like a 4 bbl nitrous injection plate, or typical common 4bbl carb spacer)
Snow Performance is just one of many good Water injection system companies.

[mustang 671]

Originally Posted by F-BIRD'88

I would not mod the blower carb adapter base plate. I'd leave that as is...I would use two 4bbl carb spacer style water injection plates (looks like a 4 bbl nitrous injection plate, or typical common 4bbl carb spacer)
Snow Performance is just one of many good Water injection system companies.

no i dont need to adapt the plate i have, it already has 2x allen keys screws in the back of it . unless they are meant for something else ?

[mustang 671]

hi guys .

had a great day today . finally got it to idle for a while at 950 - 1000 rpm. eventually it burnt off the old oil and mosture from the engine where it had been sitting . i have put 2x videos below for you to see .

i do have 1x problem still. my neddle valves get stuck every now and then . i have set them, to just show the fuel level at the sight plugs . but sometimes while its running and i turn it off the electric fuel pump carrys on pumping fuel and out into the carb and out of the breather tube. hopefully its just a sticky needle valve, will replace them next weekend and see if that fixes it .

i am getting there now. i also jacked up the back and ran the trans and got around 6 litres of dex 2 atf oil in the c6 auto box. does that sound about right ?
cheers again

[mustang 671]

hi all . i also have a trans rad cooler but a small one so intersted in how may litres or quatrs it should roughly take ? cheers

[mustang 671]

hi all . i have taken a video this weekend of my engine running with the vacum gauge rigged up to below the carbs but above the blower. there is a take off to the rear of the blower that i was able to screw a fitting into to get a take off for the vacum guage. so i have got the engine settled around 850-900 rpm and the vacum reading @ idle is 16-17 . so whats your thoughts on my power valve requirements ? cheers for all your help guys. i am well made up to have it starting and running smooth now. your posts really helped and have got me up and running. t bird . i went with your figures and they are fine at present and the engine is idleing a hell of alot better.

the video is here . cheers all

[F-BIRD'88]

The power valve will not operate correctly until it is boost referenced.
its and easy mod..
Untill that is done,, remove and block of both power valves and use rich +6 to +10 jets in the primary side
for WOT dyno testing under boost. You need to read with two vacuum gauges @WOT under full boost.
one on the carb base one on the intake manifold. They will read different.

need both upper and lower vac gauge readings at WOT Max boost max rpm on the dyno.
(this tells you how hard the blower is pulling on the wide open carbs , at WOT under boost)


make sure the vac secondaries are opening correctly on the dyno. (paper clip test on the sec diaphram linkage) These can be pesky.... leaks.

Once you ave boost referenced the power valves correctly,, I predict a 10.5" power valve will be right for your motor..... Untill that is done,,, block the power valves and jet up.

Need to know the best dyno test power jetting pri (with blocked power valves) and sec.
Then need to know the PVCR's orrifice sizes in your primary metering blocks (measure it)
(remove power valve and look)

Again, the power valves will not work right until boost referenced , with 14PSI boost.
remember start dyno tuning with rich carb jetting and conservative spark timing under boost on pump gas.

[F-BIRD'88]

If you had low 5psi boost you could do this different....But you don't.

you need to cut those ugly carb choke horns off too.

[mustang 671]

Originally Posted by F-BIRD'88

If you had low 5psi boost you could do this different....But you don't.

you need to cut those ugly carb choke horns off too.

cheers . will speak with the dyno guys as they have pv blanks and the higher jets. i am running around 11 psi which is better than what i thought at 14 psi . i do have a blower snout which is the retro looking one. is there any reason for cutting off the carb horns for any better set up ? or just coz you think they are uglily ? they will be covered by the blower snout anyway so wont be seen , i just dont put it on when running so i can see the boosters etc to make sure the needle valves have shut off