mikep2002

iTrader: (10)

Just installed long tube headers and I think I may have lost 1psi of boost. Is this possible I did notice some belt slip and tightened the belt. I am reaching 5psi on p1sc I think I had 6psi before headers. Sounds kind of funny didn`t expect to loose boost but I did gain more torque.

SMDLS1

iTrader: (9)

Your loosing boost because your engine is flowing air better. If you added ported heads you would lose more boost, but gain power.

mikep2002

iTrader: (10)

Thank You. Now my question is how do I bring my boost back up to 6 or 7 psi. I am reading alot about 6rib and 8rib belts and different pullys. Kind of new to this procharger thing and I dont really want to get into the internals of the motor. Would like to see 475 rwhp now I am at 445rwhp and 438trq. Thanks for any help possible.

NA$TY-TA

iTrader: (21)

That right there is were people make there first HUGE mistake.......
They try and up the boost back up were it was......Why???
Our cars with a stock motor will live a while on mild boost.... with a good tune.... but we get greedy and up the boost.... the power didnt go away because your running more boost now.... the headers just mad it easier for the car to breath.

All boost is, is a restriction of flow. The better the motor flows the easier it is for it to make power.

I just see it happen alot here and then down the road the persons stock motor is gone..... just FYI.... seen it done and done it my self when i first started out.... back in the day....
I havent always been turbo...

Kyle

mikep2002

iTrader: (10)

That right there is were people make there first HUGE mistake.......
They try and up the boost back up were it was......Why???
Our cars with a stock motor will live a while on mild boost.... with a good tune.... but we get greedy and up the boost.... the power didnt go away because your running more boost now.... the headers just mad it easier for the car to breath.

Thanks I just hate when somebody is talking common sense to me. I just read some of the information on this forum about how much boost you can make without thrashing your bottom end. I really dont want to jump off the deep end just really want my little 1lb back.

Thanks

EPP

iTrader: (22)

When I order an ATI ProCharger for someone, we normally will set it up for 8 psi of boost. We need to know what mods are done to the engine to determine what size the blower pulley needs to be. Headers, a cat back, camshafts, and better flowing heads all have an effect on boost. You need to find what size the blower pulley you currently have on the blower now is. You can then go down to the next size smaller on the pulley. Where many people screw up is they don't check the tune after swapping to a smaller pulley. With the engines timing in the 18 to 22 degree area, and the air/fuel ratio at 11.5/1 at wide open throttle, you shouldn't have any problems with your engine. Our Mustang Chassis Dyno will give lower rwgp numbers than an overrated DynoJet. We see 500 rwhp as the upper limit to durability, so you shouldn't have any problems. We set engines up at much higher numbers, with the customer's knowing full well they may be in for an engine rebuild. We have a customer who has an Mazda RX7 with an LS1 that we installed an ATI ProCharger D-1SC on. This car already had heads and a cam installed, it is at 575 rwhp, and has managed to stay alive for two years. Bob

Urban Legend

iTrader: (5)

The SDCE set up will get your pound of boost back and then some.

andereck

Power itself will generally not damage your engine, detonation or a slightly too lean running condition will. With boost comes heat due to the compression of your intake charge by the supercharger and the mechanical compression of the engine. With typical bolt-ons such as exhaust mods, mild cam or cylinder head porting you may turn the supercharger's airflow up to match the pre-mod boost level without too much trouble as long as you tune appropriately for it. This maintains roughly the same IAT, though in-cylinder compression temperature will go up from the increased air density. In actuality though an increase in performance and loss of boost from an exhaust improvement means less hot residual gasses are left in the cylinder and a cooler denser air/fuel mixture is in the cylinder. Your engine's threshold before detonation should increase slightly.

While it is often mentioned that "boost is just a measure of restriction" that statement is only partially true. Boost with temperature is a measure of air density. Fuel pressure is a measure of restriction. If you have a gallon of gasoline under 15 psi and another at 60 psi and you weighed them they would weigh the same. Gasoline is uncompressable and won't change in density under fuel system pressure. Intake air however is a compressable gas and higher pressure crams more oxygen and other gasses into the same space, increasing its weight and ability to burn fuel. Since we are measuring boost at the intake plenum we have to assume that a component change that resulted in a loss of boost came from an increase in available fillable cylinder volume. Whether that came from better exhaust scavenging or removing an intake restriction your engine is now able to consume more air, increasing cylinder volume and lowering system pressure. At some point in time with a well developed race engine the intake and exhaust will be able to keep up with swept volume and power increases will come primarily from driving the supercharger to higher airflow levels. This of course will increase boost pressure which directly increases air density with appropriate intercooling.
Take this example: Donnie Walsh's 400 inch Pro 5.0 @ 38+ psi and Donnie Walsh's 400 inch Pro 5.0 motor at atmospheric pressure alone. Which do you think makes more power? Why? The increase in air density from boost makes the blown engine seem like its 3.5+ times larger and can burn the corresponding ammount of fuel.

fenix99

iTrader: (1)

yea man same problem here but with a Aftercooled Vortech V9 G-trim(8-9psi). The car has headers, FAST manifold/Throttle body, and we're only seeing 5.5-6psi...BUTTTT the cars making more power than it would with stock exhaust/manifold at 8-9psi....so yea dont worry about it, with bolt ons you wil "lose" some boost but gain power due to the ability to flow and process air...Just like what everyone else has mentioned...dont get crazy with it because thats when **** starts going bOOm lol

mikep2002

iTrader: (10)

Thanks for all the help guys I am going to look into the SDCE bracket and see what is involved. I thank you all of the information. And good luck to you guys

NA$TY-TA

iTrader: (21)

Good cut and paste..

Yes thats exactly what it is but most of us dont really need to know that much info....... what was said gets the point across

andereck

Cut and paste from what?

Urban Legend

iTrader: (5)

You said that you believe you lost 1 psi of boost. Did you gain anything with the LTH's? Just curious.

Chas1

I had LT's, a catted Y, and the SDCE tensioner put on at the same time. I gained 55rwhp, 37 rwtq and 2 psi( from 5 to 7).

mikep2002

iTrader: (10)

Yes I gained approx 38hp at the rear wheels. I went with the street series just a bit smaller. I`m gonna have to think about chasing extra power. See more negs than positves. Thanks Guys

mikep2002

iTrader: (10)

I`m starting to do the math on the 8rib belt starting to sound expensive. My last dyno, my 38lb injectors were getting low on fuel. Looks like I am gonna need new injectors and the sdce kit and pretty sure a new dyno tune. This could probaly run me 1500-2000k and my steet tires now don`t hook up in first or second so tack another 500 on for drag radials. My old lady gonna shoot me if I do this, bitch wants new bedroom set.

Chas1

I can't do anything to my car for under 2K anymore. Such is the life of FI.

WAHUSKER

iTrader: (4)

I had ~9psi with a collapsed cat. When I removed it the boost dropped back down to 7psi, but I gained 15hp & a 40lbs of tq. Yes more boost = more power, but freeing up air flow does too. I am using the 8 rib setup from EPP with ATI's SFI damper + a 7.5 crank pulley.

EPP

iTrader: (22)

Once you get that new bedroom set, I'd skip 42 lb injectors and go for 60lb'ers. With a good tune they will give you great driveability, and will allow some room to grow. Bob

mikep2002

iTrader: (10)

I called procharger to try and find a simple solution and I think they found it for me. I am going with a smaller pully wheel and a new belt tells me that should give me my 1 pound of boost back. This should only cost me like 200.00 that sure as hell beats 2K.
I think I am going to still need the the larger fuel injectors possibly. Will I need a new tune done if I go with the larger injectors? Will I need a new tune with the new smaller pully wheel? Thanks for all your help.