27 replies to this topic

[kodi191]

All good except avoid the charge box. It's an old-school method and it's overly complex IMO. The only real advantage it might have is when it comes to seals as they won't see a big pressure difference outside-to-inside the float.

Simply for function the only thing that needs to happen is the fuel bowl vents need to see boost pressure so that the boost in the intake won't push fuel back into the carb. Luckily, AFAIK our carbs (at least the CDMs) vents are located within the filter circle. So after building a round carb hat the fuel bowl will actually pressurize with everything else and you don't need to do any extra plumbing.

I don't think ANY 1G/3G turbo guys have used a charge box and I have not heard of any issues with pushing seals out, so I think it's really not needed to use a charge box.

The only "real" complication wtih running boost on or carbs is playing around with the main power jet to get the right fuel mixture under boost.


If someone knows different on the vents then correct me ofcourse, I haven't really explored the carb stucture yet, these are first glance observations. I simply haven't spotted anything that looks like fuel bowl vents except the ports within the carb filter circle.

well i have the weber 38 on my car so it wouldent be hard at all to do it i dont thank and i have a good manifold on my 86 crx parts car i have but i alredy have hedders on my car

[Vicious]

well i have the weber 38 on my car so it wouldent be hard at all to do it i dont thank and i have a good manifold on my 86 crx parts car i have but i alredy have hedders on my car

so do you want to go turbo or not? cuz if you do, you'll lose the headers you sell them to me so i can finance the turbo setup you win i win and you'll be good. I want you to understand that the hf/dx manifold with an adapter plate has been the best manifold i've seen for our engines. any other manifold is custom and usually doesn't look very clean because of the welds and design. like i said just do the hf mani, coat it, mat a t25 to it and you'll be golden. you can skip the FMU since you're carbed.

[zakats]

All good except avoid the charge box. It's an old-school method and it's overly complex IMO. The only real advantage it might have is when it comes to seals as they won't see a big pressure difference outside-to-inside the float.

I meant a box/hat to be mounted on top... I guess I'm not too hip to the carb/turbo lingo!

[Vitamin J]

so do you want to go turbo or not? cuz if you do, you'll lose the headers you sell them to me so i can finance the turbo setup you win i win and you'll be good. I want you to understand that the hf/dx manifold with an adapter plate has been the best manifold i've seen for our engines. any other manifold is custom and usually doesn't look very clean because of the welds and design. like i said just do the hf mani, coat it, mat a t25 to it and you'll be golden. you can skip the FMU since you're carbed.

I'm looking into turbocharging my Si as well. I've got a stock Si manifold and a stock HF manifold. The Si mani doesn't look well suited for a turbo and the HF manifold looks so puny! Those ports are like the size of my finger! Should I pick up a DX mani to weld the turbo flange on?


Also, I have a Greddy T3 off a 1989 Saab Turbo, will this be a good size?
Thanks

[Vicious]

I'm looking into turbocharging my Si as well. I've got a stock Si manifold and a stock HF manifold. The Si mani doesn't look well suited for a turbo and the HF manifold looks so puny! Those ports are like the size of my finger! Should I pick up a DX mani to weld the turbo flange on?


Also, I have a Greddy T3 off a 1989 Saab Turbo, will this be a good size?
Thanks

the DX and HF manis are the same size if i'm not mistaken. so if you don't think the ports are open enough you can have it ported. the SI mani is not good for turbo. so just have the manifold ported and have the the adapter plate welded onto it.

as for the turbo you'll have some turbo lag running it up until around 3-4k rpms depending on trim, etc, etc..... like i suggested a t25 will allow you to run 6-12 lbs of boost and no turbo lag. granted 12lbs is pushing the little turbo but it more than enough for our cars. since you're boosting an Si my suggestion for your setup is the hf mani, t25, 2.5" exhuast, fmu, and an upgraded ignition system. oh and you can have your injectors sent off to Russ Collins you can even run the teg ecu i'm sure scott wouldn't mind since you'd be needing the extra fuel.

all in all i don't think you'd spend more than $500 bucks if you know where to look. hmt is a great source for freshly rebuilt t25s for next to nothing

[Vitamin J]

Sick, that was my plan. I'll just port the HF mani myself. I came across this Swedish POS so I'm parting it out. The T3 has a .42 AR so I'm hoping it will be a good match for the EW. I don't plan on more than 8psi

Thanks!

[Joseph Davis]

Greddy doesn't make T3, I think you mean Garrett. The .42/.48 found on the Saabs are good for 225-275, depending... those cars received 40/45/50 trim T3s across the years. I've rocked one before, if yours is in good shape you'll really like it.

[Vitamin J]

Yeah, durrrr, its a Garrett. Ya its in great shape. Rebuild kits are only $20 on ebay! Sweet, glad to know it won't be oversized.

[BigOrange]

The turbo rex kits used a stock hf/dx mani, with a T3 adapter plate. They said one reason they did it was because the manifolds were abundant so when your manifold cracked it was easily replaceable. I wouldnt port the mani personally. Its cast and not all that thick and over time from the heat it will already want to crack. Then if you port it you will really only be speeding up the process.

[kodi191]

u dont want my hedders they are bint a lil and have a small crack in em i bottomed out on them in the woods over the winter i couldent see the ditch it was covered in snow lol

[flashmatrix]

I have an HF manifold for sale if anyone is interested.

http://www.redpepper...mp;#entry453905

[rwdcrx]

as for the turbo you'll have some turbo lag running it up until around 3-4k rpms depending on trim, etc, etc..... like i suggested a t25 will allow you to run 6-12 lbs of boost and no turbo lag. granted 12lbs is pushing the little turbo but it more than enough for our cars. since you're boosting an Si my suggestion for your setup is the hf mani, t25, 2.5" exhuast, fmu, and an upgraded ignition system. oh and you can have your injectors sent off to Russ Collins you can even run the teg ecu i'm sure scott wouldn't mind since you'd be needing the extra fuel.

all in all i don't think you'd spend more than $500 bucks if you know where to look. hmt is a great source for freshly rebuilt t25s for next to nothing

No lag.....ummm your looking at 3000-3500 rpm before it spools on the d15/16. It spools at 2200-2500 on a DSM

The GS-T runs 11lbs stock on the T-25. Mine petered out at 15psi., 5000rpm, 2.0L. 12psi on d series = more than plenty.

2.5 is too big on stock t-25 and d series. stock 2" is fine. MAYBE 2.5" Cat-back, MAYBE! Remember....opening up the exhaust will get you a bit more out of the top end but you'll lose it in the spool up. I went from 2200 rpm spool up with 2" to 2800 spool up with a 3" cat-back on my DSM. You'd be around 4000 rpm on the "d" before you'd see any boost

$300 is more like it. (or less) You could buy all new shit for $500.



And yes T3 would be good on the "d"

My $.02.5

Edited by rwdcrx, 26 July 2009 - 12:11 PM.

[Vitamin J]

I have an HF manifold for sale if anyone is interested.

http://www.redpepper...mp;#entry453905

I knew mine seemed too scrawny!

This is what I pulled of a CRX HF at the U-Pull-It: