99blkfrc99

I'll start by telling you what I have. 99 FRC, manual. 243 heads, LS6 intake, VRX4 cam and supporting mods, headers, exhaust, intake. It made 375whp and 360wtq last week. I'm happy, it's fun but as you know, you always want more. I don't really want to go down the FI train because then I need to start thinking of a stronger diff and tranny. Is there anything more I can do NA to get to 450whp or above?? I.E. different head/cam packages, bigger exhaust? Just looking for a little more, well I guess about 75whp more. Any ideas out there, similar set-ups for my goal? Thanks

DetroitPlac

Stock (not ported) 243 heads? I'm a bit surprised the power number is so low...seems like this setup should be pushing 400whp without much issue.

Paul 75 L82

A good set of heads will get you where you want to go.

Rob Petyo

Trick Flow 215 heads
Fast 92 intake
EWP should net 8 - 10
vacuum pump
You said you have exhaust but ask about a "bigger" exhaust.. 3 inch pipe to High flow cats or no cats


What are your goals?

99blkfrc99

I bought the car and it had SW headers and borla muffs. It does have some sort of small universal cats on it. I'm happy with it now but would be ecstatic at 450whp

99blkfrc99

I'm assuming the cylinder heads are not ported. They were on the vehicle when I bought it.

99blkfrc99

So were talking better cylinder heads and better intake manifold? Will my current cam be ok or should I get a larger one? Also, if I get a fast intake do I also need a larger throttle body? Thanks

tblu92

It would help to know your cam specs----- Your RWHP numbers do look low for a manual trans---
Has your car been tuned after all your current mods were installed ????
If not you may need a re-tune----
I got 375 RWHP early on when modding my 98 automatic car !!!
Give us more details on your cam and heads
Are your Trick Flow heads a base LS1 or LS6 core ????

Rob 02

Is it tuned? I would think you should be making ~425HP or at least 400HP.
Your figures seem a little light. Were those numbers taken from a Mustang dyno by chance?

99blkfrc99

I did have it tuned with all my current modifications. It was on a dyno dynamics. As far as cylinder head, don't know much about them, just has 243 casting. Cam is 228/230 .588/.592 112.

Rob 02

A low rear gear can give falsely low dyno #'s.
Your #'s are what I would expect from a stock LS6 with just a CAI and a tune.
You have more cam plus headers and exhaust.

I would be curious about what is going on before modifying further.
Do you have good compression?

99blkfrc99

I have not checked compression but I certainly can. What number should I be looking for?

Rob 02

In the 180-200psi range.

Keep in mind that some dyno's show lower numbers if they present a load. Some do this to mimic road conditions for tuning purposes.

alxltd1

I am running basically the same mods as you on my 6sp 2000 coupe, with the exception of the cam. My cam is smaller at 224/224 .581/.581 114 LSA. It put down 398 RWHP/385 RWTQ on a Dyno Jet Dyno. It would seem you are leaving 20 to 25 RWHP on the table somewhere. Besides the recommended compression test, maybe another tune may help before moving to other mods.
MY mods:
LS6 intake manifold
Ported and polished 78mm Throttle Body
RHS 205 heads as cast
Comp Cam 224/224 .581/.581 114 LSA
XS Power headers through Hi-Flow Cats and into Ti exhaust

On N02 (150HP shot) Plate Wet system with dedicated fuel cell it put down 543RWHP/610RWTQ on the same dyno, a couple of weeks later. I was optimistically hoping for 420/425 RWHP naturally aspirated, but believe my heads needs some CNC work to get there

Rob 02

If the compression is excessively high then the cam may be advanced. The result would be an increase in low end torque at the expense of higher end HP.

I would like to see 99FRC's chart if it's handy.

alxltd1 may be right about the tune.

99blkfrc99

99blkfrc99

I may try a different tuner. The place I brought it too, their tuner has been doing vehicles for 15 years. He tuned one of my 240's like 10 years ago. I was going to bring it to Doug Rippie but he is living in Arizona for the winter so I did not. They are a more only corvette oriented shop which maybe I should look into when he is back. Otherwise I'll probably check compression this week.

neutron82

the dyno pulls should have been done in 4th gear which is 1:1 ratio so the rear gears wouldn't matter, now if the pull was made in a different gear that could explain the low numbers... I think the numbers are fairly low as well, I made 391 on my 02z with headers/intake/tune and I would expect the op's car to hit 400 easy... something is definitely off, are you sure the cam is what you say it is?... I would verify what gear the dyno pull was made in, do a leakdown test, and if that all checks out then I'd have a different tuner look it over

Rob 02

Okay, I read the OP's other thread. Someone with more experience with that particular dyno mentioned that it's readings are about 13% lower than a Dyno-Jet reading. I had a suspicion.

In that case your Dyno-Jet HP would be about 424HP 404TQ. That is pretty decent.
So no need to worry or spend any money on a re-tune prior to any further upgrades.

99blkfrc99

I was there the whole time, the dyno runs were done in 4th gear. I also did the correction factor from my other post, which is more along the lines of what I was expecting. I've always heard dyno jets read higher than dyno dynamics and mustangs because there is no load on the drums. I'll still check compression tho. Thank you for all the helpful responses.