4k-c Turbo?

[Nebuchernezzer]

I wouldn't mind learning to do the tuning myself as well, every time i pay for work it's crap.

Main thing i'm wondering is how mixtures are checked? Wideband o2 sensor?

I'd like to think i'm mechanically skilled, i've done an engine swap, IRS conversion and so on in the past on my old S12 Gazelle.

It's about time I learnt somthing new :lolcry:.

[Taz_Rx]

Hi, was just searching for info on carby turboing a KE70 on google and found this thread, excellent stuff :lolcry:

Anyways from my quick read of this thread i'm thinking the following would be possible:

T25 from CA18DET (or perhaps E15ET T2, i don't think they run water cooling which would make things simpler) on around 5-6psi (no intercooler nessessary at these pressures or is it recommended to have one?)

Sealed square box around stock carby (rejetted, i have no idea how to tune a carby however, as far as i can tell you change needles to effect how much fuel comes out, but how do you tell how much fuel you are getting and weather to go up/down sizes?)

Locked dizzy and remove vacuum advance

Larger electric fuel pump (has anyone tried plumbing boost into the stock mech fuel pump as mentioned in the thread?, i guess i'll need a fuel pressure gauge to keep an eye on this)

Related plumbing for turbo, water/oil lines and exhaust.

I'd be hoping for 50rwkw and a substantial torque increase.

Does this sound feasable?

I've had some experience with engine conversions and general car stuff before so fabrication won't be a problem, carbies, jets and dizzys are a pretty grey area for me though (My background is turbocharged EFI Nissans). Things like weather i'll need a rising rate reg or the differences between an EFI or carby reg are a mystery to me at this point.

Jarich

 

Hi Jarich,

 

T25 or T2 would be really good on a 4k. any turbo from a 1500cc to 2000cc engine will do, depends what you can get your hands on.

 

intercoller is very much optional on that sorta psi (as you are probably aware, the lowest boost pressure you can run is that of the standard wastegate!). I'm now running one which does make a noticable difference in under-bonnet temps, and a small difference in performance. I also run 6 and 10psi though.

 

a good way to jet the standard carby is swap the secondary to the primary and drill out the primary bigger than the secondary...if you can follow that.

with running a standard carby however your main problem is the pressure tolerenace of the needle and seat. they will only hold >5psi!! the problem being you need to have more fuel pressure than boost pressure, so if you entend on running 5-6psi you need to have around 8psi of fuel pressure, which the standard needle and seat will not hold!!! this can be overcome by using a rising rate reg, similar to what you would be accustomed to with turbo EFI nissan, but for a carby application. the only difference between them is the pressure- EFI's will use from 30psi to 100psi but with the carby ones you can set them on say 4psi base pressure (which your needle and seat will handle) with boost refencing from there on at 1:1. so by the time your on 6psi the needle and seat will be seeing 10psi of fuel pressure. with this option you can just use an EFI pump, depending on the size of it however you may want to run it through a balist resister to drop it down to 6 volts, ie my VL turbo pump is now making around 50psi rather than the 100psi it normally would!!! and half the volume.

the other way to skin the cat is to use a weber carby, ie 32/32, 32/36 etc. the needle and seats on these small webers will handle up to about 12psi, so if you use a carter black (100GHP @ 12-14psi) or similar you will then be resticted to around 10psi of boost pressure (2psi less than fuel pressure) and the needle and seat wil hold it!! in this case you would not use a reg at all!!

 

locking the dizzy is a 20 minute job, just replace the 2 springs on the mechanical advance with a couple of small cable ties!!

 

all the oil and water jazz is easy as.

 

deffinatly feasable, and the torque increase is awesome!!

 

think i've cleared up a bit of your other queries above.

 

have fun!!!

[Nebuchernezzer]

Thanks, sounds good to me, i probably have a few 32/36 webbers around somewhere since i used to own a 2L Ford Escort RS2000.

Making an adaptor plate wouldn't be to hard either.

From what i've seen the proce of rising rate regs (at least the EFI ones) is prohibitive given the overall cost of the project (like $200+) so swapping the carb might be the way to go.

 

Should i keep a stock carby is there any particular sizes that you would drill out the primary?

Would you go up by say a percentage in size or just keep trying sizes until it seems to be running well with no detonation?

 

Intercooler might be a do 'if i can get a core free' kind of thing, shouldn't be to hard to persuade a mate to part with a stock S13 intercooler for $0 :lolcry:.

Thanks for your help :)

Jarich

[Taz_Rx]

I use a weber not the standard so not exactly sure on what size to drill out to. if you PM Untubbbed_20 he would be able to tell you however.

 

I bought one of the rising rate regs I spoke about off ebay, ended up costing me $66 including frieght. :)

 

also as far as intercoolers, if you can hold of a cheap turbo mx6 cooler, you will notice just how damn easy these are to put in a rolla!! ;)

silvia coolers are like a slice of toast!! :lolcry:

[Nebuchernezzer]

silvia coolers are like a slice of toast!!

Funny you should say that, i've said exactly the same thing myself.

I have had a look at an MX6 cooler before, if i can find one that'd be good, a 1GGTE stock cooler would probably be suitable as well.

I'll probably just skip that step initially though.

If a rising rate reg can only be had for $66 then i think rejetting the standard carb and running a rising rate reg with a spare EFI fuel pump (i have a VL one in the shed) would be my favoured option.

 

All i need now is the rolla, i thought i had a KE70 lined up but it got sold 1 day before i got to it!

Ah well the search goes on.

Jarich

 

Edit: What features does a reg need to have, i just had a quick squiz on ebay and finding an adjustable regulator for between 2-15psi is easy, however there isn't any mention of rising rate (is rising rate a normal feature on regulators or do they usually just regulate to a set ammount all the time?). I suspect rising rate is an added feature and all the cheap ones i can see for sale are straight rate.

Edited July 13, 2006 by Nebuchernezzer

[Taz_Rx]

yeah it does need to be rising rate. they have a vacuum/boost line into them and for every psi of boost it gets it will up the fuel pressure by 1 psi!!

 

this is how you get a base pressure the standard needle and seat will handle and then a more fuel pressure than boost pressure when you are on boost!

[Nebuchernezzer]

Cool, everything is crystal clear now!

Thanks

Jarich

 

Edit: i had another thought, would an EFI pump (which usually runs a line into and out of a fuel rail) like having it's flow restricted by a carby pressure reg (which just runs an in and out as far as i can see, no excess fuel return the to the tank). I'm wondering if since it'll only be moving a rather small ammount of fuel it might be just spending the rest of it's energy heating the fuel up?

Running the pump on low voltage might help that somewhat.

Or i could ditch the VL pump idea and just run a proper electric carby pump.

Edited July 13, 2006 by Nebuchernezzer

[Felix]

with boost referencing the mechanical fuel pump.... i'd only maybe consider doing that if you have brand new seals in it.

 

i have a modified holley blue fuel pump and malpassi rising rate carb reg. i bought it off a guy who ran over 20 psi of boost into into a blowthru 3k. he modified the internal bypass in the holley blue, making it capable of over 25 psi output. the holley blue pumps normally run a dead head regulator, but with this mod it has to run a return style reg.

 

whatever fuel pump you use, it must be capable of your base fuel pressure + whatever boost level you run.

 

i wouldn't bother with the stock carbs. they aren't really very tunable.

 

whatever carb you run, you need to increase the secondary jet, and reduce the size of the secondary air bleed. the rule of thumb that i saw on the old blowthruturbo yahoo group was to halve the area of the secondary air bleed. doing this makes the carb enrich the mixture more under load, and stops it running pig rich under normal off boost driving conditions like increasing the primary jet would do.

[Nebuchernezzer]

whatever fuel pump you use, it must be capable of your base fuel pressure + whatever boost level you run.

Since external EFI pumps like the VL unit are so easy to get hold of thats why i was thinking of using one, they can probably hold 80-100psi happily, if i have to run a reg with a return thats fine with me.

Main reason for going with a stock carb for me is that i'll be doing this for fun on an old banger, i don't want to spend a cent more then nessessary really.

If it can get 60rwkw on the stock carb then i think that will do me just fine, I think that will be an adequate ammount of power.

If i'm unhappy with that then i'll see if i have a 32/36 Weber at my parents place and look into that path.

Rich off boost driving isn't too much of a concern since both myself and my girlfriend have nice daily drivers already.

Since this will be our thrash car it'll probably spend most of it's life on boost, however if it's nice and easy to do i'll look into playing with the secondary air bleed instead of changing the primary jet.

Doing the jet sounds easy as though.

[Boost+k]

forgive my ignorance but what does the secondary air bleed look like? i'm thinking of going back to standard carb on mine... i'm sick of the su. its such a c**t on cold mornings.

 

i had another idea for fuel reg. get a holly carb reg and then carefully drill a hole in the top and thread a niple on there run a vac/booost line to that and it will boost reference itself? what ya recon?

 

and Nebuchernezzer i don't think you could run a efi pump on a carbie reg without a return line because you'd have to stall the pump or it'll keep building up pressure unless it has its own internal relif? don't the vl's have little regs on the side of them?

[Nebuchernezzer]

and Nebuchernezzer i don't think you could run a efi pump on a carbie reg without a return line because you'd have to stall the pump or it'll keep building up pressure unless it has its own internal relif? don't the vl's have little regs on the side of them?

Yeah that was my thoughts, the VL pump does have a little reg on it but i wasn't going to use it since i don't really know what it does, i could have a closer look and see though it might be somthing like that (which would be convenient).

I guess the easiest way would be to run a reg that has two outlets for fuel, send one to the carby and one back to the tank or even just back to the line before the fuel pump.

Not sure how else you would manage it though.

Electric carby pumps don't back up like that?

[Taz_Rx]

sorry that something I should have added. YES the rising rate regs DO HAVE return lines!!!!

 

some (like the one I have) has a fuel in, fuel out- to the carby, a return line to the tank, and the vacuum line.

the rest are more like an EFI malpassi being used ON THE END of a fuel rail. they have a fuel in, return line and the vacuum line. the way you can set these up is have a hose coming from the pump, then t-piece it with 1 line going to the carby and the other going to the reg.

 

some EFI pumps have relief valves in them, but they are normaly in-tank pumps and squirt the fuel out of the body of the pump, so you can't use one of these out side the tank without filling your boot with fuel!! :lolcry:

 

boost+k, I suppose that idea with the holley reg would work as long as it was a diaphram. but do they have a return line on them!?

[KE354AGE]

Hey guys, i have read through this whole thread, just quickly though i must admit, and i didnt see much, if anything on compression... pull me up if its already been discussed.

 

what compression are you guys running? from what i have read it sounds like alot of you are just running pretty stock motors.

i was thinking of building a turbo K motor just for fun because i have a couple of 3ks and a 4k laying around and also a TD04 turbo sitting there doing nothing.

i was just going to stick it on the 4K because its the bigger capacity motor, then i got to thinking of using a 3k bottom end and a 4k head to drop the copression a bit, to make a more boost friendly combination.

what do you think of this? has anyone done it? or is it just better to use the 4k for its capacity advantage.

[Taz_Rx]

6 of 1, half a dozen of the other on that one.

yes you will end up with lower compression with the 4k head on the 3k.

but it the 3k going to pass enough gas to get a tdo4 moving!! its only 100cc less than the 4k so maybe.......one way to find out I guess!!! :lolcry:

 

oh btw, yes we are just running stock C/R. I have changed the compression **at time of firing** in the top end by having the dizzy locked!

[Falken_KE30]

I'm going to try the 3k block, 4k head thing one day,

main thing on these motors is right turbo, need a small one.

 

simon, your running the CT12 right?, what about a CT20? you could try one of them seeing as yours runs outta puff.