Old Janspeed set up

[bula]

Hi all, was put onto this forum from TR7.com as wealth of knowledge dealing with turbo installs on here and from what I've read so far will probably sort out my teathing problems....finally! Are you sitting comfortably? Then we'll begin. Story so far then, purchased a garage find 80's janspeed setup on a 3.5 RR 9.35:1cr have no other details on it apart from the guy getting shot of it bought it off another guy who decided after a while it was too scary a ride to use in his swb Landy off-roader so I know it worked....once upon a time The plenum is a branded Janspeed item as is the exhaust manifold/turbo mount (so assuming its a conversion kit which I believe they did back then for SD1's etc) Partially stripped it retaining most data/settings for future reference but (schoolboy error!) not it seems the important ones. Managed finally to get the thing running and passed an mot but driveability doesnt figure in the test. Standing/idling small acceleration everything ok but underload foot down the thing splutters and dies and wont start runless its had bloody ages of cranking! Very embarrasing as I live in a dip, hills on both sides so need throttle to go anywhere further than the drive! Have fitted a facet red top gold flo to try and combat the starvation and junked the sytec pressure reg in favour of a malpassi rising rate one as it was obvious the fuel ran out when the boost started coming in. Not sure what to look for re a blow through set up on the carb but again assume its all matched because of the conversion ( but you know what they say about assumption! ha ha) The carb is a Weber 40 DCNF 12 with afr settings all to f%$& need advice to get it running okayish to limp it to the local rolling road & Carb specialist 15 mile away but not relishing the day or so needed to chug it down there (lots of hills!) help help help!

[Jono FD3]

My bet:
When the set up was put on to carb engines (all turbo carb for that matter) the fuel float chamber needs to be presureised by the turbo aswell or the pressure from the turbo is going to be blowing the fuel back in to teh float chamber instead of in to the engine! so, basicaly the janspeed setup was run on the SD1 with twin SU carbs, so my guess is this engine is a bitsa, and some one has eather bought the turbo setup 2nd hand for the engine and just bolted it on (with out modding the carb for + pressure) resulting in fuel starvation when the turbo starts to spin..... or they have changed the twin SU's for a webber thinking it will get better performance!!

Eather way I recon the carb is for an NA setup and not a forced induction one

Jono

[bula]

Float has been changed for a plastic one instead of the brass original which would figure if its been setup for + pressure to stop it collapsing.

[Jono FD3]

no no, it's not the float thats the issue.....
Fuel gets drawn out of the float chamber through the jets via suction/negative pressure in the inlet manifold caused by the pistons dropping in the cylinders with the inlet valve open..... now if you put a positive pressure in to that inlet track you will be forcing the fuel back to the tank, unless the carb has been modified to run a forced induction system (basicaly equalising the pressure in the float chamber and intake manifold) and fom memory the webers don't like this setup which is why you normaly see them used as a draw through and not a blow through setup. this would give you the symptoms you are discribing with fuel starvation when you put your foot down..... turbo comes online and blows the fuel back in to the carb internals resulting in no fuel for the engine to run.

Jono

[mcmental]

ive just picked up a janspeed twin turbo setup for my hotrod and shall be fitting it over winter, i shall be watching this thread very closely.

[bula]

Got diverted away from the twin setup by an old motorway copper who used to drive the RR back in the days, bags of grunt but only any good if you had a 100 miles of straight flat road to wind it up in. Bugger to get balance right too apparently. As it is I'm having headaches getting one set up lol have you managed to find anyone Janspeed related to shed some light on data etc? In 2 years of trying I've always drawn a blank
Jono I suppose I've got to go down the route of a Holley then?

[bula]

Or is getting hold of an efi inlet a better solution?

[mcmental]

The lad I got it off had no problems with it, just setting carbs was his only problem he said.

[Jono FD3]

From what I have seen the holly is an easy option for turbo setup as they vent the fuel float chamber in to the carb intake somewhere so the float presurises along with the manifold when the turbo comes online so no mods are needed on them....
But at the end of the day if it's all about the power and drivability, injection and MS would be the way to go as you can map the injection to suit the boost you are running..... but if you go down this road, don't forget an adjustable rising rate fuelpressure reg for increasing fuel pressure at the injectors when the turbo comes online. Using injection you will probably gain 30bhp or even more and you will know it is bang on once it's all dialed in

[JP.]

but underload foot down the thing splutters and dies.........
Have fitted a facet red top gold flo .........!

Thats not suitable for turbocharging.
The Facet Red Top has not enough pressure to overcome the turbo pressure.
Out of boost youll need about 6 psi fuel pressure
If you'r running about 7 psi boost your fuel pump has to deliver 6+7 psi =13 psi fuel presure. Thought that Red Top are good for 7 psi only.

You'll need a fuel pump thats capable of at least 20psi.

Been there, done that.
I am using an Capri injection pump which is good for 90psi of presure. The Malpasi rising rate regulator will work fine with this pump regulating it back to 6psi.
Capri injection pumps can be found cheap on ebay click click

[mcmental]

Thanks for the info

[bula]

Thanks JP, Malpassi data says will regulate from 0-60psi and or back so any aftermarket pump that pushes idle+boost (Webber likes around 3.5 I believe) and have no idea how much the snail I've got will deliver if I go for a safebet of around 20-30psi then, should all be "appy daze!"
Ps Now have a surplus Facet Gold flo Redtop, very very little usage LOL so if you know anyone who's after one, pm me please

[chodjinn]

but underload foot down the thing splutters and dies.........
Have fitted a facet red top gold flo .........!

Thats not suitable for turbocharging.
The Facet Red Top has not enough pressure to overcome the turbo pressure.
Out of boost youll need about 6 psi fuel pressure
If you'r running about 7 psi boost your fuel pump has to deliver 6+7 psi =13 psi fuel presure. Thought that Red Top are good for 7 psi only.

You'll need a fuel pump thats capable of at least 20psi.

Been there, done that.
I am using an Capri injection pump which is good for 90psi of presure. The Malpasi rising rate regulator will work fine with this pump regulating it back to 6psi.
Capri injection pumps can be found cheap on ebay click click

I can guarantee you I was using a facet red top with filterking on my old twin turbo set up without any issues, but I'm not sure what the psi was, probably between 5-10psi.

[Fozwanger]

Excuse me for seeming a bit dense, are you using it as a suck through or a blow through?
I had (still have but not on a car at present) a TT set up sucking through SU's. All I can say was it was a doddle to set up, a fine tune on a RR for £100 and it performed faultlessly for years.
Both suck and blow through have their pro's and cons, I personally think that suck through is far easier to install and set up, only downside is you can't (or sghouldn't ) use an intercooler as the fuel can drop out of suspenion in t he cooler and I had to run the car rick at tick over so that it almost stalled to get the AFR right at full throttle.
Loads of people described it's performance as "monumetal" or" mental" and I too used a filterking reg and a rallye design cheapy red top copy (as my redtop failed)

[chodjinn]

Excuse me for seeming a bit dense, are you using it as a suck through or a blow through?
I had (still have but not on a car at present) a TT set up sucking through SU's. All I can say was it was a doddle to set up, a fine tune on a RR for £100 and it performed faultlessly for years.
Both suck and blow through have their pro's and cons, I personally think that suck through is far easier to install and set up, only downside is you can't (or sghouldn't ) use an intercooler as the fuel can drop out of suspenion in t he cooler and I had to run the car rick at tick over so that it almost stalled to get the AFR right at full throttle.
Loads of people described it's performance as "monumetal" or" mental" and I too used a filterking reg and a rallye design cheapy red top copy (as my redtop failed)

Not dense at all, I used suck-through, which would explain why the red top pump is sufficient. Blow through would no doubt be a different matter, as mentioned above.