Well as the title says I'm building myself a 383 for the z28. Already have spent some good amount of time figuring out what my overall goal is and that's roughly to be around a 120mph trap in the quarter.

As far as the build. It'll be a 11 to 1 motor for compression. Already have got the rotating assembly and have it figured out with the trickflow 195 62cc heads it should put it right on the money. As far as camshafts I have decided that I believe the xfi 292 will support my goals as I have seen numerous people on here with the 268 and 280 have great results. To see how the rest of the car is currently setup just look at the signature.

The only curiosity I have is trying to get the proper injector sizing. I myself believe a 36# injector will be just about right but then maybe a little bigger would be safer? As the car currently is, I can peg 115-120% duty cycle depending on the day with the current motor and 24# injectors

 

At stock fuel pressure, 30 lb SVO's feed up to 600 hp at the crank just fine.
Ignore that duty cycle number that the data programs report. It's meaningless.
Wideband AFR on dyno tunes still responds to fueling adjustments long after that bogus value has passed 100%.
There's no reason to run more than 30lb injectors for your power goal. Any larger just sacrifices driveability/tuneability at idle/cruise.

 

I have this combo with the 280XFI. My Trickflow heads are fully ported to flow 298cfm @ .600 lift with 2.05 valves. I'm also using the Miniram. I hope to get in that range with the G-Force T5. 30lbs injectors will be cool.

 

292XFI in a 383 is better suited with 210 heads. That size duration cam in a 383 would also be pushing the envelope of hydraulic roller lifters. That cam will peak around 6500 rpm and not need shifting until7000 or so. The XFI cams are good choices but you could do just as well with a cam of less duration and a tighter lsa. I ran a 280XFI in my 383 and swapped it out for a cam with a touch more duration and a lesser lsa, 113 down to 110, and single pattern.Idle quality so far seems the same and midrange feels better.

 

Yours is one of the few builds I have kept my eyes on over the time actually. The horsepower I will get on a dyno doesn't really matter, as they are far and few where I am located. Its why I have an mph at the track kinda goal. Our racing weather around here is anywhere from 4500-6000Da. The best air around here is spring and late late fall, where its maybe 2600-3000.

If the budget allows for it I'll be sending the stealth ram and the heads off to spanel for some port work, if not it'll happen later in the year.

 

If you go with the 280XFI instead of the 292 I can send you my MegaSquirt file from that engine. You would only need to make a few fine tuning tweaks. I have a MegaSquirt III extra.

 

I have a similar setup on my 350 with the TFS-195's and Victor-E but with an XR276HR (or whatever its called now in their catalog) and 36# injectors, and the 36's are a good match. The % DC matters, but over 100% is meaningless since they are open all the time. Mine are at around 80-85% at 6,000 RPM, which gives a little head room.

 

What was your e.t and mph with your combo?

 

What was your e.t and mph with your combo?

 

Never made it out to the track but from my tunerpro datalogs the best 0-100 MPH time was 11.4 seconds. 0-60 is just under 5 seconds if I can manage not to burn through 1st gear.

The 2.77's I have currently have a pretty crappy gear spread. Probably take it once Im done building my new rear with better 3.23 gears I picked up.

 

Thats gonna make it real tough to go 120 mph on motor.
Best chance will def be the fall air but that still is thick.

How heavy is car?

I would not use the tfs heads as cast, they will need ported and springs set up to match the cam. I would get titanium retainers and hollow stem intake valves if possible, else just get morel lifters, 3/8" pushrods and very stiff spring. 175 lbs seat 450 open at around .600" should do it.
I'd like that cam with a touch tighter lsa. Maybe just install in 2 more deg advanced. It should get the job done if the heads are good

Stealth ram will need extensive port work as well. 7000 rpm shifts.

 

The car last time I had it on scales was 3400 race weight. Had no intentions at all of using the springs that came with the heads as I know they can't control the xfi ramp rate, iirc the springs I was looking at is the 914-16 by comp. Have no problems with a 7k shift point, had planned on it. I know that our DA around here is a killer, the mph goal is for pretty much our October/November racing.

If the budget allows it the heads and intake will find themselves at Spanel, which is about the best race shop in our state. They build a lot of the competition drag guys motors with great results. Otherwise I'll send them there at the end of next years season.

 

My mildly ported hsr 383 with afr 195 eliminators and a custom 230/245 .603/.613 109 lsa cam went 119 in about 2000 ft DA at 3450lb. Thats what i am referencing for your power. Abit more cam and abit better intake port work and heads will do it. I just dont think the tfs will out the box.

 

I would second that. The stock springs with those are pretty useless. Im using comp beehives with morels on my setup. Works good to 6k, but the morels are pretty heavy lifters and 7k+ is probably what this setup calls for. Might get better results with a rev kit and a lighter valve spring since it would have better dynamics.

 

Well my idea for a spring is comps 914-16. My other choice in cams that I have been debating over is the lunati 294/302. I've heard lunati specs its cams on 1.5 so if that is correct it would make it a .593/.598 or right around there on a 243/251.

 

Thats a good cam, lots of top end. I would go 210cc heads with afr 8019 springs if you dont already have springs

 

Well it probably won't be until the end of this month before I get around to getting a cam ordered. If I was to stick with the xfi292 would the 914-16 be enough to control it, I had read that was used I believe on Vincents car to control the 280 iirc. But I've been keeping the lunati line in mind quite heavily. I just don't know what rocker ratio they use for rating cams.

Don't have springs yet for the new build. pretty much just the bottom end and the heads/intake. Sticking with my TFS 195s that will be either ported here later this winter or at the beginning of next winter (along with the HSR).

 

They might work ok. Have good seat pressure and nice amount of open pressure. Just a very heavy spring at over 1.4" diameter. But should be ok with lighter valves to 7k rpm

 

The engine ate the air cleaner stud just before the engine could be considered fully broken in, so I never got any times or dyno with that engine. What I can say is that the cam I went with makes more midrange power based on my VE tables. People should be less afraid of cams with a tighter lsa and/or a smaller exhaust duration. Supposing the exhaust side of heads, headers and exhaust is sufficient that is.

 

I have dual Manely Springs and a light weight valve train with 2.05 valves in my Trickflow Heads. I bought my heads in 2002.

 

Decided to lean away from the xfi and go for the lunati 294/302. I think it'll be better suited for making that power N/A then the xfi line up.

 

If you are really set on runing a cam that size in a 383 I think you should more heavily consider a 210 head and not be relinquished to a 195 just because it is what you already have. Tony Momo is a smart guy who is heavily involved in the design at AFR and is regular enough of a guy to go on message boards and help out guys. This is a direct quote from him helping out another member in your situation:

Whats the right head for this application.....in a very heavy car you might consider the 195 Comp port....a 300 CFM+ head with a very moderate cross section, or step up to the 210 Comp which would also work well in the application you descibe, especially if you always run quarter mile (versus eigth mile) and the car isnt very heavy (less than 3400 with driver).

In pure track application with the cam you describe and healthy static compression for pump gas (11 - 11.25 to 1), the 210's would likely produce the best results, BUT, the 195 Comps might 60 foot a little better ET just shy of the 210's and probably trap 1-2 MPH less.

However....if you care at all about street manners, throttle response, and drivability, the smaller 195 Comps would get the nod there and run just a tick or two behind the 210's at the track as I descibed above.

In the order of pure track performance yuor choices would be...

210 Comp head
195 Comp head
210 Steet head (least expensive option....same trap speed as the 195 Comp with less ET due to a softer 60 foot and eigth mile time....not as crisp on the street)

Hope this helps...

Feel free to call me at AFR if you would like to run anythinig else by me

(661)257-8124 Ext 109

Cheers,
Tony

PS....You dont have a single bad choice in the bunch....only good choices that will place various emphasis's on the combination!

PSS....the 195 Comp head would rip to about 7200 RPMs with an explosive midrange (and the best part throttle perfromance)....the 210 Comps would likely see an additional 2-300 RPM before running out of breath and would require a 7400-7500 shift point for maximum effectiveness.

 

Here's a short clip of my combo.

 

Thought I would give an update on the status. Motors been in the car and running now for about a month. Just been spending time playing with the tune for driving, have yet to start playing with any wide open tuning yet.

Seems to pull extremely well tho despite the tune being pretty rough. Need more pump and injector however which is on my list for this coming week, I knew it would but kept the smaller injectors in to ensure I kept my behavior tamed. Won't have track times until next month when the track is finally open, dyno numbers could be a lot further away.