VincentZ28

iTrader: (2)

Who has made good power with 355cu XFI280 and Super Ram?

Orr89RocZ

iTrader: (20)

i have been doing alot of cam research since i'll be doing one on my motor soon.

I've always was a fan of the XFI stuff and tended to recommend them. i wanted a 224/230 custom xfi, or the 280xfi 230/236 cam, but decided against it for the simple reason of valve control

its been said its VERY hard to control the valves at rpms over 6000 where that 280 cam will like to shine. its really aggressive ramp rate and aggressive over the nose. you'll need expensive lightweight titanium retainers/beehive springs for that cam or else you wont beable to rev much over 6000

now with superam, you'll want your peak power probly well below 6000. probly peak in the 5500-5800 range.

that 280 will work well and make power but you'll be leaving abit of performance on the table. i'd shoot for a slightly smaller cam like the 224/230 xfi, or even the smaller 218/224 xfi 268. that cam will be good for solid 350whp. i've seen an lt1 with good heads put down 370whp with the xfi268 but that doesnt seem to be the norm.

Else you could go custom grind.

Guest

I do have TI retainers (came with the heads) but not beehives. Standard weight valves. No float that I've experienced as of yet, limiter on the MSD is currently at 6800.

Dyno Don

iTrader: (7)

After the extensive dyno session yesterday and analyzing the results with Datamaster, I do feel Allen is definatly getting in to valve float with the XFI 268 and beehives.

The scans show that the map is fluxuating up and down all the way thru the rpms from 5000 to 6000.
It starts at 101 then bounces to 97 98 100 96 98 etc etc.. That would seem to indicate intake reversion. (ie. valve float)
The dyno shows power pulling to 5000 then flattening out to 6000 maintaining the same power or there abouts.
We might try some better beehives that Manley has. 150-360# but I'm sure we need to lighten the valve train.

Orr89RocZ

iTrader: (20)

sounds like more seat pressure is what you need, along with lighter valves and retainers.... but sounds like its already pretty light as it is.

maybe try LS1 hollow valves, they are suppose to be pretty lightweight

1989GTATransAm

iTrader: (3)

Vincent that cam will most likely work out very well for what you want to do. I think you have bigger fish to fry for more power.

bdiroc

Bringing back from dead

Vincent I changed my cam from lpe 211 to xfi280 and changed springs and ported my old edelbrock heads gained about 30 cfm peak still only 250s max

First time at track ran 12.28 @111 air da was 2200

I also changed headers from 1 5/8 to 1 3/4 dons

Now changed exhaust to 4" after dons headers but haven't been to the track since change to see results. Had 3" ultraflow before

Car leaves very lazy off the line, 1.72 60ft, I have 3200 stall but seems with this cam it's not enough.

Currently have 3.50 gear thinking of going to 4.10 to help car leave the line and stay in powerband.

Orr89RocZ

iTrader: (20)

Yeah did a car with that cam and it would like a 4000 stall to work best imo

bdiroc

Do you think the gear change will be a good band aid or should I just send converter out for restall?

Orr89RocZ

iTrader: (20)

Gear can help but how much will your rpm change at the stripe? Dont over rev it

But more converter to me always seems like a better idea than gear, but again depends on what your rpms do at end of the track
My ls1 car only picked up .06 from a 3.73 gear swap from 2.73 with the same 3200 stall. I think my 60 ft would have improved same or better with more stall. But also didnt fully optimize shift point with the 3.73. May have been some gain there but doubt it was the 2-3 tenths I expected

VincentZ28

iTrader: (2)

Did you retuned the car after the cam swap? My car so far went 119.62 in the1/4mi. Still tuning

bdiroc

Yes tune was way off with new cam, had to up injector to 30s also since i have a fixed pressure regulator at 39 .the 24s were struggling to keep up. I am not done tuning yet either, it's in ballpark just haven't had enough time to fine tune yet

I also expected more mph, heads cc'd only at 173 after port work and porter said speed was crazy on them. So probably just to small for big power. But it is a fun car to cruise in

Think if I change gear so it's in proper rpm at finish line, now crossing around 5100 need 6300 or so and a better stall it will get in 11s easy

Orr89RocZ

iTrader: (20)

If 173 cc and velocity is high then likely are not getting everything out of that cam for the cubes. A 350 or so engine will want around 1.95-2.1 csa head port to get to mid 6500 ish rpm for that cam, and also an intake manifold with a relatively shorter runner. 10-14" or so roughly. Thats normally your 185-200 cc heads

bdiroc

Sorry guys just realized Vincent asked about super ram, I have an hsr intake. That's why I'm shifting at 6350, don't think super ram would be happy at that rpm no matter what

bdiroc

Porter told me they were the worst heads he ever tested, I have had them since the 90s. No ports or chambers were really consistant and flowed less than quoted ,a lot less. Flowed 213 at .6 and only 201 when tested thru head and hsr combo.

But his flow bench is stingy, my afr 210 competition ports only flowed 288 on his bench same day. These are for next build ,hopefully this winter.

VincentZ28

iTrader: (2)

Turn your fuel pressure up to min 47psi with the 30's injectors.
I bought my TrickFlow 195 Heads in 2002. The flow was 258/191. They were ported in 2013 to 303/217 with 2.05 intake valves.

Orr89RocZ

iTrader: (20)

That will hurt power potential but sounds like its doin all it can with the port size. Dyno to be sure of your power band

bdiroc

Yes my goal with this round of mods was mid high 11s and a fun street motor. that is about all these little heads can do if I get all the supporting mods for them I think. Could get a good bit faster if I made it a drag car only.

Hopefully make it to the track this weekend to test new exhaust, then hopefully change rear gear next week and test that weekend. then local track is closed for the year.

I am going to dyno this winter to see what is really going on, cam might be a little to big for these heads. Heads want to make power down low and cam starts to make power up high.

bdiroc

Well da was a alittle better 1830, only change 4 inch exhaust, 60ft .03 better
60ft 1.718
7.74 1/8 @89.5
12.13 1/4 @112.48

Pretty happy with change, but 4" ultraflow is a little to loud cruising around town.

Hopefully do gears this week and test sunday