CHRISPY

OK so how about this. If I want to make peak power at say 6200rpm, use a 6400rpm shiftpoint and stick with 3.42 to 3.73 gears would you recommend the Vortech with a 2.5 or 2.75 pulley?

What cam?

What exhaust combo? (I currently have modded MAC's but still stock collectors) Willing to change

How much boost would I lose going with a custom air to air setup versus the air to water with upgraded pump? (Say if I used a 3 core ATI cooler with custom piping?)

I have 98 PCM what MAF scaling/adjustments would I have to make? Would I make it safely to the 550RWHP limit with the limited scaling of the 98 MAF tables?

Would 42#'ers be enough for 550RWHP or not? (at say 60psi FP)

Thanks for any information you can provide

S_J_H

I have tried a hotcam and a stock cam. Not much difference in power between the 2 cams. The hotcam showed less boost especially in the midrange.
at 6400rpm, a 2.5" pulley would put your blower at 70,600rpm.
To risky IMO. So go with a 2.75".
I really don't know how much boost will be lost with a big intercooler.I sort of doubt it's worth it with a G-trim and only 10psi or so unless you plan on running in hot conditions.
I'm running MAC's modded with 3" collectors. My last track times were with fully closed exhaust and cats though.
I think I can pick up 20hp with dual cutouts
42's will be enough for 550rwhp but they will be pretty much maxed.Mine are at least.
I plan on running some wet fuel fogged into the blower inlet to compensate using a boost switch.I only need 50-75hp of fuel so it's not a big deal.Plus it will cool off charge temps a few degrees.
I want to stick to one fuel from now on( race gas).Using alky worked well with the 2.85" pulley but not with the 2.5" pulley.
With 42lb injectors being maxed out, that was just to much low octane pump gas flowing for water/alky to combat the low octane reliably and still run enough timing for max power.
I had no KR with a 2.85" pulley.Switching to a 2.5" gave me 10 degrees Knock retard with the tuning I had been using and the same water/alky flow.I had to flow more water/alky and drop timing 4 degrees to stop it.
I was flowing over 20gph. That's a lot of wet flow and I did not want to go any higher.
To me this showed the water/alky had reached it's limits of effective detonation control with the pump gas.
In car wideband showed around 11.5-1 A.F.
I run a re-scaled and calibrated 85mm maf that reads to 67+lbs/min. I flatline it around 6000rpm in cool weather.
Just some tidbits to chew on.

RyanJ

Steve, do you just run water now...no alky?

what tranny are you running? same 4L60? T400?

CHRISPY

Thanks for the responses guys

Are you saying a intercooler wouldn't be worth while on 10#'s boost? That I could get away without one at 9:1 comp and 94 octane? Or that I should look at race gas or an aftercooler full time?

2.75 pulley sounds good.

I gained 16RWHP NA from running an offroad Ypipe versus dual 3 inch carsound cats. You will probably pick up a lot more power than that

If I go blower I would be running a 160 stat with both fans on at 170ish and off at 165. Nice and cool. TR6 plugs gapped at .030. I am not running AC and have a lot of airflow improvements under the engine. (Pretty cleaned out under there)

As far as cams my initial understanding was that it would be good to try and maximize flow through the engine (especially exhaust side) so you can move the same cfm at less boost and thus lower your octane requirements, allow more timing and make the same power with less boost.

Thoughts appreciated
Chris

ChrisB

I would still do the intercooler - with this one http://www.fastblackcar.com/camaro/t...C/DSCF0199.JPG and a T-76Q trim temps were never more than 15 or so over ambient (at ~14lbs of boost on a 383 LT1). Pressure drop at 14psi was -0.6-0.9 psi (had a Map on either side of the intercooler). Temp drop across the intercooler was as high as 78 degrees. (15 degrees over ambient - 35C).

I think pump gas would be fine - at 9:1. You may be able to pick up a few more hp with race gase and more timing, but I think your goal of 550 should be fine on pump gas.

On the cam - you want to minimize "restriction" flowing into the heads, but you also want to minimize overlap. So there is only so much you can increase the duration before you start having increased overlap, or have to go really wide on the LSA. It is normally wayy easier to reduce the restriction by porting the heads or increasing displacement.

S_J_H

RyanJ ,I had been running 50/50 water/alky.I am going to run straight race gas next year and no water or alky.I am still running my original stock 98' 4l60e.Low revs have saved it.I do have a th400 that will go in when it gives up finally.
Chris, I really don't know if it's worth it or not to try and build a nice air/air intercooler because of all the plumbing loss.Only way to find out is to try it.I was looking at the nice AC evaporator core from this car and it would make a nice liquid/air cooler with a little fab work.It's 9"/8"/3" with 15 fins per inch.Box it up add a pump resivoir and coolant radiator and you have a nice liquid intercooler.
But there really is not a ton of heat to be dealt with from only a compressed air charge of 10-14psi on a cool day.I might try it just to see down the road.
I think pump gas and no intercooler will demand greatly retarded timing though.
yes your right as long as you aren't dumping charge flow out of the exhaust.
I think with the high flowing heads you plan on using, a smallish cam will do exactly as you wish.

CHRISPY

When you say smallish cam what specs are you thinking? I want to maximize area under the curve from 2K-6200rpms

Crunch

I use 218/224 .527/.534 114
It works great and has a nasty lope.
I was worried that it wouldn't lope hard enough to sound badass, but its just fine.

CHRISPY

See I am coming from the 230/230 112LSA XE-R lift side of things...

I am used to an aggressive camshaft. that one seems puny in comparision hehe

Crunch

The thing is, we are dealing with two schools of thought in terms of making maximum power in a ~346ci:
1) Naturally aspirated - High Compression, very aggressive heads, very aggressive cam, very high engine revs.
2) Supercharger - Low compression, mild heads, mild cam, low engine revs.
Running N/A you squeeze every last drop out of the motor.
With the blown engine, you let the supercharger do all the work.
Trying to mix and match the two schools of thought is sure to compromise horsepower somewhere.
Remember, you have to scale the motor back considerably in preparation of the blower installation. You can't just take a *****-to-the-walls high compression, big cammed, N/A 440RWHP 346ci motor and then slap a Vortech ontop and expect to get another 150RWHP. Some of the very things that give those great N/A numbers have to be sacrificed in order to let the blower do its job.
If I was to take the blower off my car, I would have a low compression, 390RWHP, high 11-second car. But with the blower, I have a 530RWHP, mid-to high 10-second car (I hope!).
You kind of have to decide which way you want to go.

S_J_H

If you don't care about having a motor that lopes, then a 02 ls6 cam would be a nice choice IMO.
Crunch has nice cam specs also.

CHRISPY

I was thinking about the 02LS6 cam actually. That with stock LS6 heads might work well for me

Pro Stock John

iTrader: (34)

I also like the LPE cam that looks like a 02 LS6 cam with more lift.

I have my 230/236//115+2 cam that actually does not lope all that much now that we cleaned up the idle.