Here is my current setup:

383 LT1 (Lunati Sledgehammer Crank, Oliver Billett rods, custom Diamond pistons)
TPIS CNC LT1 AFR 180 heads
Custom Camshaft 244/254 @ .050, .578/.578 lift, 114* LSA
Hand ported LT1 intake manifold
Hooker Long Tubes (1 3/4 primaries)
Hooker Y-Pipe
Borla Cat-Back
Lingenfelter 58mm TB
60# Injectors
M6 w/Moser 12 bolt and 3.73's
EPP Custom FMIC setup
CR 8.8:1
Dual Walbro 255 lph in tank fuel pumps (2nd one kicks in @ 4#'s of boost)
Snow Performance Methanol injection system

All tuning was done on pump gas (93 octane) and on the stock PCM




My question is, if I changed out the Headers to some kooks 1 7/8 primaries (over the current 1 3/4), and chaged the heads out for some ported AFR 227's, along with a ported LT4 intake, what kind of RWHP and or boost changes could I expect to see? The biggest gains should be in the heads really as my ported AFR 180 heads are really the biggest choking point for my car currently.

I am thinking 10 RWHP from the headers, maybe another 10 from the intake, and I really don't know from the heads. Not sure what the boost is going to do either. The 180's are restrictive which is good for boost, so not sure if the larger heads will bring down my boost levels or not. On a cold day I usually see 14 ish #'s of boost (every once in a great while I see 15#'s).

Anyone have any accurate estimates here?

 

You would see larger Gains changing the blower to an F1a and running more boost. PLUS its a hell of alot easier than the work involved to change the heads!!

 

The 180 heads are killing the power. That was more than obvious on the dyno after 6,000 RPM. It would be robbing me even more if I went with an F1A.

For the most power, "yes" I should upgrade to an F1A, AND the larger heads and intake. However, I can't seem to bring myself to upgrade to the larger blower knowing I am already starving it as it is.

ramair96ws6, how is traction for you with your current setup? Are you an M6? If so, at what point in what gear do you get full traction with the hammer down?

As it is, I can run on the street with guys running almost a 10 flat just because I can completly hook up in 1st gear. I love that so much, I may end up doing nothing and just sticking with my current setup.

 

get rid of those horrid nitto's and get some mickeys, and you can still hookup with more power....

 

Okay, before this thread starts off getting scewed from the get go, I am really just interested in my questions pertaining to the original post. I don't want a debate on what performance wise I should do, or which tires hook better than others.

Just interested in how much power would be attained, or what boost difference I could expect.

Thanks

 

I would say that you are going to lose anywhere from 2-5 psi thru out the rmp range with the AFR227's. This is not a bad thing tho. You can easily get that back with a pulley change without buying a new blower. I'm guessing that with the heads, headers and a pulley change to get 14-15 psi of boost, you will be right around 700 rwhp.

 

I am already maxed out as far as the pulleys go. 700 RWHP is about what I was guessing as well. I am also guessing that it really will show a bit more torque though. Currently I am at 555 RWTQ, I would guess almost another 100 to be added there as well.

Anyone else have an educated guess?

 

That's a hard one. xxsaint69xx had the exact setup you are describing and he was dropping 700rwhp if not a little more. You're power band is definitely going to change and even though your boost level will drop the power will increase. W/ that kind of $ to do that swap, the head unit would probably be the better choice for the same results.

 

If I sold my D1SC for a good price, then bought a new F1A, then "yes". However just dropping the $ on an F1A compared to an LT4 intake and the heads, I don't see it.

Either way they both aren't too far off, and the money isn't that big of a deal. Its more of what I want all together on this. Really I am just gauging power and boost levels. The fact that if I surpass the 700 RWHP mark (800 if I upgrade to an F1A) just simply adds more factors. To me, numbers like that are pointless unless you just want dyno bragging rights (never really been into it personally). Because after a little more power than where I am at, you're not going to be beating anyone unless you are doing some high MPH roll racing against, as you will just spin everywhere.

As it sits now I can punch it in 1st with non heated Nitto's and hook up fine. This has enabled me to beat lots of guys who are a bit more powerfull than me. Too much extra power, and I'll start getting beat by slower guys with more traction. It's just more or less what I want to do, and right now I just want to have an idea where I will be at power wise.

 

i know people are always wanting more power and we always will. but if i had your set up as it is now with 600+rwhp and was getting great traction in first gear with the least best drag radial tires on in, i wouldnt change a thing except for the tires.

you have a beautiful mean a** machine that isnt just a dyno queen. i noticed in your sig that you have another car with less power, i would be modding that car and not your lt1.

im not trying to tell you what to , its just my opinion. either way goodluck bud.

 

I run Hoosier 27 11.50 16 quick time pros. the car does well once at the top of second, first gear is useless... But, I have a lot of suspension work on the car. Full coil overs afco shocks, wolfe sway bar, etc....

This car makes 690s rwhp to the wheels all day with trick flow heads out of the box. All i did was change the springs. I am also running the stock intake. No port work performed on anything.

Boost fixes everything if you don't believe me look at a grand national....


What is the intake you have running to the blower?

 

thats what I was getting at earlier. i've seen several cars with higher HP than yours, running faster than yours that dead hook on the street.

I would get the heads and a new intake now. Have you looked into maybe a sheet metal intake, or even just a single plane with an elbow yet?

spin with more power? get stickier tires. Not that big of a deal.

 

Just put a kit on it, spray it in 2nd and up.

 

700rwhp IMO is about right.

 

In a round about way, you just gave yourself the answer by this statement. If the blower is pullied out, and can only deliver 15 psi of boost with your current setup, you're not "starving" or "choking it" by any means in my opinion. The whole point of the blower is to build boost, not become a restriction. I dont think better flowing intake tract is going to net you much for the cost. Now on the other hand you sell the d1sc and get an f1a and cram 25-30 psi of boost in there, then we're talking. I know you want to hear someone tell you better flow is going to get you tons of power, but more boost is going to net you more power across the board vs. the minute amount of power you may pickup from better heads/intake.