question on inlet pipe diameter - f1 procharger

[TraviZ28]

The inlet on the f1 and for the most part, all prochargers are 3.75" but due to space constraints I can only run a 3" pipe without interference from my brake master cylinder and chassis-to-blower clearance. Am I hurting anything by downsizing from 3.75" to 3"? this is an f1 pullied for 13psi on a chevy 383. Would I still get the required air without damaging anything?

[big_G]

Inlet piping is very critical. I just dynoed my D1SC 'Vette (18lbs. boost) a few weeks ago and on the last pull I removed the inlet aitr tube and K&N filter and picked up 50 RWHP.The dyno operator says he's seen that happen many times before on blown engines.

[wicked68]

The inlet on the f1 and for the most part, all prochargers are 3.75" but due to space constraints I can only run a 3" pipe without interference from my brake master cylinder and chassis-to-blower clearance. Am I hurting anything by downsizing from 3.75" to 3"? this is an f1 pullied for 13psi on a chevy 383. Would I still get the required air without damaging anything?

You are not going to damage anything - its just not going to have the same hp as if you ran a bigger pipe.

The other thing you need to understand is that you need to overfilter it vs underfilter it as most do.

call k/n tech support - give them your engine specs and blower and they will tell you how much airflow you need in cfm and which filters wil work for you. you need to take measurements of the box are that you are going to mount it in so you can figure out what will work for you with them in raw outside dimensions.

good luck.

if you are racing - get you some wire mesh with a nice clamp that you can simply secure over the inlet to give the blower virtually unrestricted air flow in and yes you will pick up a good bit of hp. jsut make sure you tune will compensate for the increased airflow.

[TraviZ28]

Any thought input on how much boost I would aproximately loose on this 3.75" - 3.0" reduction? Could I make it back with a smaller pulley?

[camcojb]

Any thought input on how much boost I would aproximately loose on this 3.75" - 3.0" reduction? Could I make it back with a smaller pulley?
no, it's not a boost issue, although that will be limited somewhat, it's an airflow issue. You DO NOT want to restrict the inlet of a Procharger, especially a larger unit like an F1.

Been there, done that with a D1SC, and it cost me 300+ rwhp. And I didn't reduce the inlet size either, I just put a 180 degree bend on the inlet to run a cold air system, did not like it at all. Reducing that inlet size nearly 1" will really lower the power and how the boost ramps up, and trying to spin the blower faster isn't going to help, will probably aggravate the situation.

Jody

[TraviZ28]

Thank you, I will have to re work this out. I really need an air filter but my engine bay does not support one.

[DeltaT]

Another example: I picked up another 1.2# of boost switching from a 4" ribbed hose inlet with a tight 180' bend into my Vortech T-trim, to a series of long 4" mandrel bends heading down to a monster 11"Hx7"W K&N can. The midrange and topend all needed more fuel to handle the additional airflow, and the motor seemed to rev faster.

Figure out something creative and your motor will really wake up! Consider making a Y-pipe and having 2 smaller pipes with remote air filters feed your blower, or some sheetmetal trimming for clearance. Creativity will pay off here. Take a look at the K&N site to get some ideas.

Jim

[wicked68]

no, it's not a boost issue, although that will be limited somewhat, it's an airflow issue. You DO NOT want to restrict the inlet of a Procharger, especially a larger unit like an F1.

Been there, done that with a D1SC, and it cost me 300+ rwhp. And I didn't reduce the inlet size either, I just put a 180 degree bend on the inlet to run a cold air system, did not like it at all. Reducing that inlet size nearly 1" will really lower the power and how the boost ramps up, and trying to spin the blower faster isn't going to help, will probably aggravate the situation.

Jody

I run an F1-R on my engine - and I agree its not good to restrict it - however as he was saying he might not have a choice - unless he has room to put the filter off the back of the unit in the engine bay which would be better than going to smaller piping and restricting it.

A filter is going to add restriction as well btw.

you can spin it harder to overcome the air restriction however - just make sure you count your teeth on both of your pulleys and where you have your rev limit set at so that you do not overspin the unit and damage it.

you may also get into belt slippage with a rib belt at higher rpm. that would be a decision to go to a cog setup to overcome this if you have room for it and depending on what kind of driving you are doing. if this is not a daily driver and its mostly racing and low miles around town to show it off a few times a year - cog will be great - not recommended though for daily driving.

[wicked68]

Figure out something creative and your motor will really wake up! Consider making a Y-pipe and having 2 smaller pipes with remote air filters feed your blower, or some sheetmetal trimming for clearance. Creativity will pay off here. Take a look at the K&N site to get some ideas.

Jim

I did that on mine and it worked great.

[TraviZ28]

Here is photos of my dilemma..

[69X22]

I wander if you went with a manual Wilwood M/C would you clear up some much needed space and still be happy with your brakes?

[TraviZ28]

I'm afraid of manual brakes, I never drove a car with them, and I don't know how they react and if they are any good for street performance.

[carguy502]

Correct me if I'm wrong, but I think plenty of guys are running a manual M/C. With as large of a cam as you have, you probably would be satisfied with it.
:1st:

[69X22]

Talk to Frank (Prodigy) he has allot of experienced with them and can hook you up with a good deal. Also deals with allot of ProCharger stuff.

[wicked68]

can you not move this further forward to the front of the engine bay? This is insaneley close to the back of the engine and is really not workable. can you post some pics of the whole engine bay from different angles please.

I know this is not what you want to hear - but.....

also - are you not intercooling this?

what kind of rubber tubing is that? looks like radiator tubing almost - and what kind of clamps are you using on it - those look like regular hose clamps?

are you using a regular small pvc vent valve for your valve covers? do you have oil collectors on them? how about a baffle inside the valve cover to prevent oil from being forced out the vent?

I think you have some areas you are definately going to have to rework here to get it to run properly.

[TraviZ28]

I will get you some more pictures today, if I moved the blower forward I would need a new crank pulley and everything else would be out of whack I'm afraid.
No intercooler, its only 6psi and I want to do meth injection instead when I get into real boost.
The tubing is whatever came with my kit. It has held up fine so far.
Those are not pcv valves, only plastic elbows. Made for good ventilation during engine break in.

[DeltaT]

I switched to manual brakes and as long as you do it right, with the proper combo or proportioning valve, MC size and pedal config, it's great. I like it more than the on/off feeling of my old American power brakes on the sedan.

That would free up some valuable 4-6" just where you need it.

Jim

[big_G]

I too have manual brakes. Makes much more room for the air filter. I'm even going with a 9 inch K&N to help with power loss.

[4086D9]

Im running manual brakes on mine as well....work just fine. It allows me to run a big ol K&N right off the Procharger.

[Gtrpunk23]

In m

[Gtrpunk23]

I used a 90 and went out into my fenderwell A)bc of space limitations and B) to draw fresh air. My pictures are not on this computer I will try to get them up tomorrow. The car isn't running yet but I have pics of it mocked up.