ty_ty13

iTrader: (42)

just curious as to know who is making over 550rwhp on stock heads with any kind of blower.... later this year i will be on the quest to find out what is making my setup pull hard up to 12.9#s of boost and then drop off all the way to 13.8 #'s

im wondering if its my camshaft, heads, or headers.... it has to be one of the three for it to keep building boost but not make more HP...

i have 1.75 slp headers, 241 heads with unshrouding of the valves and mild CC work, 224/236 .601/.602 114lsa cam....

it pulls real hard up to 58300rpms where it peaks at 572rwhp@ 12.9 #'s and then starts dropping HP all the way up to 6300 at around 13.9#'s....

the valve springs are patriot golds with less than 1k miles on them shimmed up to spec since i had a valve job...
well i just thought about some thing... i also have stock lifters

when winter comes ill either call tony mamo or brian at TEA and have them set me up with atleast a 225cc head and have them bump the compression up to around 9.0-9.5 and run a cam that they like with either some 2'' headers or 1 7/8.

right now it has the 7.62 crank pulley with a 3.4 BP at 5800 rpms its about 8k impellar rpms below max.

the motor is a 408 with gmpp, and aarons elbow (super nice piece for the money!!!) the A/F is dead on 12.0

im concerned about why it doesnt make more power upstairs but i wont be able to spend money on it till fall/winter but i'll be thinking about it all summer.

Thanks,

Tyler

EPP

iTrader: (22)

Tyler, what air filter do you have on there? I don't remember which one it is, but we've seen good gains with a larger air filter. Bob

eb02z06

iTrader: (18)

Just like Bob said-check the filter and also double check to see if the BOV isn't slightly open. Also was the cam straight up or degree'd in. I have seen some cams off as some 7 degrees of advance.

9silverbird8

iTrader: (19)

Belt slip?

ty_ty13

iTrader: (42)

i'll check the filter size as im sure it cant hurt... but what you guys aren't picking up is that my rwhp is dropping although im gaining another # of boost...

i didnt realize that my boost was as low as it is.... so that gives me some comfort to know that my stuff is atleast flowing decent and doesnt have alot of restriction...

ty_ty13

iTrader: (42)

nope no belt slip... no dust... map keeps a steady rise the whole pass...

ty_ty13

iTrader: (42)

the only thing i can think of is the camshaft... since i dont see a huge boost number it means its flowing pretty well and not causing a restriction.... or maybe the stock lifters..... or maybe the exhaust...

would a lack of exhaust flow cause a higher boost number (more restriction) or would it just drop power up top like im doing now?

kp

iTrader: (34)

Not to ask a dumb question but are you sure the throttle is opening 100%?

Those headers suck, but really shouldnt be hurting you that bad, either way they need to be changed out sooner or later.

ty_ty13

iTrader: (42)

are you asking about the TPS sensor / absolute TP or are you asking if the physical tb blade is opening all the way?

i'll check both but i wante to see what you may think the problem is.... yeah those headers were my first "real" mod to the car and i didnt know better at the time i wish i had spent that money on some QTP headers...


would 1 7/8 headers be fine or would i need the 1 7/8 stepped to 2'' with 3.5'' collectors?

im looking at the holley 1 7/8 headers with the spear in the collector becaues i get an awesome deal on all holley stuff...

ty_ty13

iTrader: (42)

the cam was not turned.... it was put in on a motor horse with a degree wheel.

kp

iTrader: (34)

Anything 1 7/8 will better then the SLP headers, those were cool in like 1999

Look down the TB and make sure the blade is opening all the way and not overcentering or any thing goofy like that. I have seen people troubleshoot a car for a whole season because the throttle didnt open all the way.

Also double check the a/f isnt going rich up top, not all widebands are created equal.

I would also pulley up the blower some, more air the better with low compression and large cubic inch.

ty_ty13

iTrader: (42)

checking the TB should be easy enough.... from EPP's wideband to mine the fuel ratio looked almost identical...
right now i have a 3.4BP on the d1sc.. im scared to go any smaller since i dont have the sdce piece... although if push comes to shove and i cant find anything else i might try a larger CP (around 8.7'') and put a 3.7 pulley on...

its just money right?

RedHardSupra

iTrader: (1)

i'd suspect either fuel pressure dropping off (it's usually proportional to the rpm^2) or intake temperatures being so hot that they make less power than when on less boost.
do you have any logs?

ty_ty13

iTrader: (42)

the IAT is something i will also need to log when i got out and make some spirited runs... as long as the A/F is solid and i dont see a huge jump in the VE table wouldnt that mean the fuel pressure is fine?

RedHardSupra

iTrader: (1)

there's a lot of variables involved, so it's hard to notice just one thing being off, especially if it's off a little bit not just dead completely