nubs4ck

So, I've been trying to do research on a combo for my car. I had a low oil pressure problem and it is now apart at a shop. I need to decide what to do when putting it back together. My goals are 600-650rwhp on 93 octane only and I will be adding meth injection to go beyond that definitely don't want to exceed 800 as this is a street car.

Setup before it broke (02 camaro, M6, 3.73):

LS1 block "bored out" with oversized forged pistons. 9:1 with stock heads
forged Rods
forged crank
241 heads, stock with "extreme" comp cams springs
The STS kit was modified with bigger piping, a FMIC, 60lb injectors and a T66
Stock LS6 intake

I have attached pictures of the cam spec sheet as well as the dyno.

The dyno looks very disappointing, I think it may be because of the cam, I would like some feedback.

According to the shop, the only parts that aren't salvageable are the block and crank.

So, what I need from you all:

What should I do to reach my goals? I want the car to be pretty tame while cruising on the street.

Should I use the stock 241 heads with the 9:1 compression ratio, or should I go for the 6.0 heads (bought a pair of 317 castings)? Or should I go with a completely different set of heads?

Should I keep the cam that is profiled here, or should I go for a different cam? I don't know what is possible as far as valve train limitations, but I would like to spin the motor up pretty high, is 7k out of the question?

I was planning on replacing the crank with a stock unit, as it should hold the required power. Is this a good or bad idea?

In order to reach my power goals, it has become evident that I will need to upgrade the turbo to a better flowing unit. What turbo should I go with, knowing that 800 is the absolute maximum I would ever want to go?

Does anyone have an idea why the graph sucks *****? Turbo motors should increase in hp, not decrease.

I was also planning on getting a turbo k-member, in case I wanted to move the turbos up next to the transmission at some point, but I'm not sure that will ever happen. Is there any downside to upgrading the k-member for a street driven car?

I'm looking forward to some feedback, as I need to finalize this as soon as possible. The problem is that I wasn't planning an upgrade, but a few weeks after I got the car it came apart so I'm forced to do something and I'm already paying all the labor at the shop.

I'm hoping to hear from some of the guys out there that have a similar setup to mine (rear mount turbo with 346 forged bottom and a MT).

1CAMWNDR

iTrader: (21)

Your cam looks fine. Your air fuel ratio on the other hand is grenade lean for a turbo motor. At WOT you want closer to 12:1 AFR on a turbo motor. Do you plan to get another aluminum 5.7 block or would an iron 6.0 block be possible?? Stock cranks have lived to 1000 rwhp so that will be fine if properly balanced and installed with quality components.

nubs4ck

I was planning on sticking with the Aluminum block. The shop found a used one for $550.

The 6L iron block has a 4" bore, correct? The pistons I have aren't that size, so it would be an additional cost. I think the best iron block option would be the 5.3, as it has a slightly smaller bore. What is the advantage of going to an iron block besides potentially holding more hp and them being a little cheaper?

yeah, I wasn't happy about the afr, but it will be getting a new tune after break-in. The AFR doesn't really go past 12.5, that sounds safe, right?

Btw the rings are going to be Total seal coated rings with zero gap.


Side question... How many of you boosted fellas are running a FPR without a boost reference?

98Z28CobraKiller

iTrader: (17)

Target AFR for an FI application should be in the 11.2-11.9 range. Ideally in the middle USUALLY. Different setups like different AFR.

No reason to run an aftermarket FPR and not make it boost ref. It'll help stretch your injectors.

Go for the extra cubes of the 6.0 to help the lazy rearmount. Also, the M6 isn't going to help much in real life driving on this setup.

nubs4ck

I don't think an iron block would be a good idea for me, I'd like to keep the extra weight out of the car, and I don't plan on making extreme hp numbers. I'm pretty sure the stock block wouldn't have a problem holding up to 800hp, am I right?

On top of the other questions..

Can anyone answer why the hp/tq curves look like crap? Doesn't it seem weird for a turbo car to reach max hp at 5k?

1CAMWNDR

iTrader: (21)

That's probably the 241 heads choking trying to move that much air. And the AFR. The power peak will depend on what turbo you have. Turbos generally make a lot of torque once they spool up and carry it without dipping untill some other part of the engine dictates an airflow drop.

nubs4ck

Do you really think that the 241 heads are choking on a stock displacement motor above 5k rpms? The air may be pressurized, but it still flows the same CFM as a N/A car with an equivalent cam save for and extra scavenging flow... at least this is my understanding.

I am wondering why people are running 9:1 SCRs on these cars with boost. Most vehicles I know of coming stock from the factory with turbos were in the 9 or below category. I believe the old DSMs were 7.9:1 or so.

What is everyones DCR? With the 241 heads I should be at 6.83 and with the 317 heads I would be at 6.47. Assuming I was running 15#s of boost on the 241 heads, I would be at the same cylinder pressure with 16.7#s with the 317 heads.

Anyone else have input?

1CAMWNDR

iTrader: (21)

I think it is a combination of the heads, AFR, and small turbo. 317 heads, spot on tune and a properly set up 70-76 sized turbo will make gobbs more power and torque.