Twins With Blower

[boosted_gem]

Hey been talking to a few mechanics and been getting different answers just wondering if anyone can clarify.

 

If i am running twin 40mm sidedraft delorto's and i wanted to bolt on a blower could i just make an alloy air box over the two carbs and run the blower striaght into that or would i have to put the carbs infront of the blower. If been told that if i bolt of the blower and put an air box striaght over the varbs the car wont run properly

 

Just wondering on peoples thoughts

 

Cheers nathan

 

PS i know i make need a decomp plate which i can get made up so thats not an issue

[Redwarf]

What model Corolla?

[styler]

hey you can have suck through and blow through setups apparently, i thought you could only get blow through superchargers which seem to be more common from what i have seen.

 

well on turbo setups if you have the carby blow through setup then it has to be modified to take pressure as well as retuned to suit I'm guessing. else buy a carby that is blow through from factory like a sigma turbo carby or an aftermarket one designed for turbo applications. you can run an intercooler on this design for higher boost levels.

 

if you have it suck through design then a retune is all thats needed afaik, however you wont be able to run an intercooler on this setup, so only a moderate amount of boost is avaliable.

 

and both setups have to run quite rich all the time afaik.

 

this turbo info probably applies to your supercharger setup.

 

from what i have seen people don't tend to run turbos or superchargers through

twin sidedraft/ downdraft carbs but rather use a single carby on both suck through and blow through setups.

 

actually a couple of k series motors have been supercharged at low amounts of boost, id get onto those people for advice.

 

plus there are many different types of superchargers for a start! I'm guessing you want to bolt on a 4agze charger with custom brackets, have it non - intercooled, use a decompression plate or lower compression pistons, make custom piping, rebuild and modify a carby to suit and have about 6psi max on non forged internals.

 

a guy at toyota wreckers at sumner park brisbane is also putting a supercharger on his 5k at the moment.

i think he may be using a commodore one and is getting the head flowed too.

Edited August 25, 2006 by styler

[boosted_gem]

Basically i want to bolt a sc14 blower on to the side of the block but my main concern is that i want to know if the carbs i have would be able to suit this application without having to run a suck through setup. i have a pair of twin DLHA 40mm delorto's on a reline manifold. I know that things will eventually brake if the install is not perfect but to start with i just want to run the blower with a decomp plate and go from there.

[Redwarf]

Yes, but which model Corolla are you fitting it to? Some have more space limitations than others.

[boosted_gem]

Sorry about that forgot to note what corolla i had its a Ke55 coupe a space will not be an issue for an air box as i can work with the dimentions that i have to make a correctly sized air box

 

Cheers nathan

[irokin]

Well its gonna have to run rich all the time. Carbys don't differentiate between pressure levels. All they see is a pressure drop across the venturi. That pressure drop might be 1psi natually aspirated, then add boost and the pressure drop is still going to be 1psi. I might not be explaining it best, someone else might be able to help. Carbys off turbo cars have a pressure compensator and add more fuel as the pressure rises. Ive always thought using twin charade turbo carbs on a corolla twincarb manifold (they should bolt up from my research) could be a good way to go. Theyre off a 1L motor so two of them should be good for a fair bit of power. They can take some boost, I knew a guy who was running 20psi through one on a charade :y: making 200hp!. Apparently theres a problem with them blowing the seal out around the throttle pump, there must be a fix for it though.

[boosted_gem]

Well i've decided to buy the blower and bolt it onto the twin delortos using a decomp plate but now i have another problem any one know what thickness the decomp plate should be to lower the commpression of the motor i believe that i the compression to be able 7.1 or so

 

Cheers nathan

[styler]

some reading material...

[Boost+k]

i wouldnt bother with a decomp plate. they arnt very good. but you havent mentioned what motor were talking about here?

 

i would blow through the twins , i've seen a single delloto being blow tho, if would be rather hard to set them up but at least you can change jets etc to get it right. the main thing you'll need is a rising rate fuel reg.

 

the main problem is with the supercharger you'll prob be boosting at idle (and i can't see the motor liking this much) so what i'm doing to get around this is still running the factory clutch set-up and running the switch setup off a adjustable shift light and then i can set it as i want depending on conditions.

[kryton brown]

You can go blow through ok as long as you can seal where the fuel line and throttle cable exit the box and like ^ he said, you use a rising rate fuel reg..

[boosted_gem]

Besides a decomp plate how could i lower compression without changing pistons or could i just go a decomp plate and see how it go's the decop plate i can fabricate myself so it is not an issue to get the plate

 

cheers nathan

 

The motor setup is a 4K block with a port and polished head with a 290 degree cam and extractors and a 2 1/4 exhuast with the twin 40mm delorto's

[Boost+k]

you can mill the head to have bigger chambers. most 4ks are about 9to1 so low boost (upto about 12psi) if fine for pump gas.

 

and you can go for a thick copper headgasket.

 

i would reconmend getting arp head studs etc..