Added fresh bottomend (306), ported intake, and longtubes...gained just .8 mph...why?

I've always had a some interest in you and your car because you remind me of myself. You seem to have a pretty decent head on your shoulders, you reason through problems pretty effectively, and argue to learn - all traits we have in common. I also had a combo that was virtually identical to yours. Ported Cobra intake, FTI cam with similar (though if memory serves slightly more aggressive) specs, and AFR 165s. I swapped to BBK 1 5/8" long tubes from my mac shorties. That combo is long gone now, but hopefully me running the piss out of it will lend me a little credibility. Here's my take on it:

1. Run the RPM as high as you're willing to run the engine - I took it to the edge shifting at 6200 rpm, which is just shy of the stock limiter. I can tell you for a fact, without even computing based on your dyno that shifting a few hundred rpm higher will improve your times, if only a little every little bit counts.
2. bump the timing from 16* to 18*. I did a good amount of dyno-tuning with my old FTI combo and 18* was definitely the sweet spot with those heads.
3. Open up the flanges at the end of the collector in the BBK headers. They have a 2.5" collector, but for some reason beyond me, they tightened back up to about 2 1/4" after the collector, which to me defeats the purpose of having a complete 2.5" exhaust system. This was with my BBKs, which I had more than 3 years ago, so check to make sure my info is still accurate. I actually measured mine, so I know my info was accurate at the time.
4. Weather often accounts for shifts of 3-4 tenths/mph. If you want any type of meaning to your track times, you need to record the DA which can be calculated by the track's elevation, temp, humidity, and also get the wind speed and direction in relation to the direction of the track. Without this information, you're wasting time trying to compare small changes in power on the track. This is one of the biggest reasons you shouldn't listen to a noob who swaps his paper filter for a K&N and runs 3mph better the next weekend. He'll swear his new part be it a clutch, gears etc have picked up power, and it may well have, but his less than scientific methods aren't credible. The atmospheric and track conditions can make noticeable differences.
5. As already stated, you're engine isn't fully broken in. I remember that in circle track racing I always turned my best times at the end of an engine's life, and it was a considerable difference.
6. Your porting on the performer probably didn't help much. The stock intake isn't going to be a restriction for the amount of power you're making.

I think you can get another 1-2 mph out of the car as it sits by shifting higher and resetting your timing. It's been a long time, now, but it would run 88-91 mph on any given day with the old combo. I think I was probably a good 100 lbs lighter than you, though.
 
A buddy of mine has a similar combo to yours and this weekend, we indexed the spark plugs. I noticed a big difference and I wasnt even driving. You can get the washer kit for $15 from moroso. No numbers yet, but I'd guess he got 8-9 hp. Just a thought, I know its a little off topic but it might help you out a little. Im going to be indexing my plugs in my 347 this weekend.
 
get one of those cam lift measuring tools off summit, or just look up the grind/part number on the net. I think its the cam. Also, maybe you just hit ur max power before u did the 306 and u just have the strength now, but not the power. Maybe u need to upgrade your MAF and injectors so u can get more fuel.
 
i have a 93 cobra computer kit that will make the car run like stock with stock emissions, but will have the extra fuel, timing curve and air you need. Its the X3Z computer with 93 cobra 24# FMS injectors and 93 cobra 70MM MAF, they all work together to give you great drivability but the extra power you need if you have more air going in from a cam, porting or heads installed... let me know man, its in the classified section
 
It needs a 347 :D... sorry I could resist.

Whys does the driveshaft rub? If it rubs what is your pinion angle at? Most of your gains with the long tubes would be more noticable in the 1/4mph over the 1/8 mile.
 
Probably didnt pick up as much just on the account of it being a new engine, older engines can run just fine (not always) and new engines generally take awhile to loosen up. The 4 cubic inch gain can just as easiely be offset by tighter clearances, tighter ring gap, ect ect. Who's to say the car really picks up much with the ported intake or that it's working within your desired RPM range? Or that the stock tach is even getting you in the rpm range you need.

I think it's all that making fun of the 5.0 finally catching up with you. ;)

Nice advatar! Who is it?! peace


john:p
 
I've always had a some interest in you and your car because you remind me of myself. You seem to have a pretty decent head on your shoulders, you reason through problems pretty effectively, and argue to learn - all traits we have in common. I also had a combo that was virtually identical to yours. Ported Cobra intake, FTI cam with similar (though if memory serves slightly more aggressive) specs, and AFR 165s. I swapped to BBK 1 5/8" long tubes from my mac shorties. That combo is long gone now, but hopefully me running the piss out of it will lend me a little credibility. Here's my take on it:

1. Run the RPM as high as you're willing to run the engine - I took it to the edge shifting at 6200 rpm, which is just shy of the stock limiter. I can tell you for a fact, without even computing based on your dyno that shifting a few hundred rpm higher will improve your times, if only a little every little bit counts.
2. bump the timing from 16* to 18*. I did a good amount of dyno-tuning with my old FTI combo and 18* was definitely the sweet spot with those heads.
3. Open up the flanges at the end of the collector in the BBK headers. They have a 2.5" collector, but for some reason beyond me, they tightened back up to about 2 1/4" after the collector, which to me defeats the purpose of having a complete 2.5" exhaust system. This was with my BBKs, which I had more than 3 years ago, so check to make sure my info is still accurate. I actually measured mine, so I know my info was accurate at the time.
4. Weather often accounts for shifts of 3-4 tenths/mph. If you want any type of meaning to your track times, you need to record the DA which can be calculated by the track's elevation, temp, humidity, and also get the wind speed and direction in relation to the direction of the track. Without this information, you're wasting time trying to compare small changes in power on the track. This is one of the biggest reasons you shouldn't listen to a noob who swaps his paper filter for a K&N and runs 3mph better the next weekend. He'll swear his new part be it a clutch, gears etc have picked up power, and it may well have, but his less than scientific methods aren't credible. The atmospheric and track conditions can make noticeable differences.
5. As already stated, you're engine isn't fully broken in. I remember that in circle track racing I always turned my best times at the end of an engine's life, and it was a considerable difference.
6. Your porting on the performer probably didn't help much. The stock intake isn't going to be a restriction for the amount of power you're making.

I think you can get another 1-2 mph out of the car as it sits by shifting higher and resetting your timing. It's been a long time, now, but it would run 88-91 mph on any given day with the old combo. I think I was probably a good 100 lbs lighter than you, though.

Thanks, I have the same feelings toward you and your car:)

I measured my BBK collectors and it was 2.33"...I imagine they needed it 'slightly' smaller than the H-pipe so that it helps a bit more with sealing issues. Most cars aren't going to be able to get the longtubes/h-pipe straight on with each other. So it allows a little 'flex'...

I'm also running FULL accessories (minus smog), and no tune, and 3,160-3,170lb car with 210-220 lb driver at the time...and suspension is poo:) That is why I look at the mph...

I have 224*/224* at .560/.556 lift...lsa at 111*, cam powerband is 2600-5600 rpm if I recall, I don't have the cam card with me currently...

I want to shift it higher, but I'm not sure how accurate my stock tach is...so it is just a guessing game...


Now a few comments, now the engine has roughly 5-6k on it. Then it didn't have as much. I still have not bested that time of 8.27 at 87.31 mph in the 1/8th. My local track that I frequent is 1000 ft. long. and before the longtubes, lower intake, 306, I was running 10.65 at 97.98 mph. After the swap and 1000 or so miles, I ran 10.55 at 99.31 mph. So a gain of 1.33 mph over a 1000 feet.

I understand weather can make huge differences, but that is comparing my best to best, so I would hope they get close to averaging out.

Tmoss told me I would gain with a ported lower...he never said big gains, nor did I expect any, but it matches the AFR 165's a bit better, so I know it isn't hurting:)

I could probably try 18*...

All in all, I have had a priority shift and I'm putting the money I earn towards more meaningful things in my life right now. I need to concentrate on finishing my degree and going for my MBA/grad. school afterwards, girlfriend, and plans I find enjoyable. So money is not going towards the 5.0L for a while...I need to get life going first....I have had my fun...and will have more later once I get a career going:nice:

Plus I would like a dcc controller, fix my sunroof, and a nicer suspension first...make it more driver friendly:nice:

Thanks Chris for the thoughts, I take them in with full consideration!

Rick - The 1000 foot track is 280 feet short of a quarter mile, I don't think it would have did to much in the higher rpms from there on out. Longtubes seem to benifit lower-mid rpm (first 60 feet?). Oh, and the driveshaft doesn't rub anymore...I didn't really know why it was there for a while...not saying the problem is fixed, but it just sort of quit:)
 
A buddy of mine has a similar combo to yours and this weekend, we indexed the spark plugs. I noticed a big difference and I wasnt even driving. You can get the washer kit for $15 from moroso. No numbers yet, but I'd guess he got 8-9 hp. Just a thought, I know its a little off topic but it might help you out a little. Im going to be indexing my plugs in my 347 this weekend.

I have indexed my plugs before by using just spark plugs. I just tried different ones until the electrode pointed towards the exhaust valve, using a different combo of plug tolerances/torquing, and saved a few bucks on the indexing kit.

I imagine the indexing kit puts the plug electrode/spark in and out at different locations...

I think indexing can help a horsepower or so...this is new plugs replaced with new indexed plugs, not old plugs swapped out for new indexed spark plugs:)
 
Hey, there's a first time for everything! While I've got you agreeing with me, maybe I can convince you to ditch those Too-Fing-Slow heads for some Amazingly-Fast-Race heads.