Thinking of doing a roller conversion from my flat tappet Comp XE268 to either a roller 268XFI or a 280XFI. Thinking that the 280 might be a bit big for the Superram on my 355. Comments?

 

What heads

 

Heads are Trickflow 175cc 10.5 to 1 compression flow 242 cfm @ .500

 

ZZ9 cam, LPE 219,

 

The duration, lsa and power band of the 280 is a pretty good match for the Superram. The only issue I see is the lift and your heads. The gross lift with that cam is .576/.570. Your heads are flowed at .500. Be sure for one thing that your heads are equipped with the higher lift, dual spring package for .601 lift. The base springs cap out at .501(.520 coil bind). Also, talk to Trickflow and see how those heads flow at .600. They should be able to tell you if they go into stall above .500. As long as they continue to flow at least 242 at .600 and you have the springs to handle the lift, I think the 280 will give you good results. It will have a bit of an idle if that's what you like. What kind of EFI controller are you using? Is it programmable?

 

Heads flow 245 cfm @ .600. using stock ignition and tuned pcm. Going to Accel system for tuning when I do cam change. Maf to speed density change at that point. Ran 12.80@108.8 with current setup.

 

280XFI is too much for those heads. I should know. I'm using Trickflows 195 fully ported with 2.05 intake valves with my 280XFI in a 388cu. Made 440whp at 6300 with a Miniram. Check my sig. You have smaller heads so you don't need that much cam. What intake are you using?

 

Using Edelbrock base with the superram. Have Hawks thirdgen ram air intake boxes through k&n filters. I think for me its between LPE 219 and the comp 268XFI. Comp is newer lobe profile and a bit bigger but the LPE is proven with the superram.

 

Vincent, impressive results on the dyno. For your compression, heads and the Miniram, have you considered the XFI292? Your engine could probably benefit from the longer duration.

86redIROC, my same warning applies to the XFI268. Check the specs on your TFS heads. Unless they've changed things, they load their heads with a decent single spring suited to a flat tappet cam with .480 or so lift. Switching to a hyd roller with way over .500 lift, you need their upgrade dual spring package, unless you bought the heads with the dual springs installed. It's a good dual spring with 420lbs/in that works well with something like the 268 or 280.

EDIT: If you bought the heads with the 1.25 springs, then you need to do some shopping for springs that will handle the higher lift. Talk to Trickflow about it.

 

Heads are getting ported 5 angle valve job, bowl work etc. Edelbrock base is getting ported along with Superram. New 1.6 roller rockers, pushrods and springs. Think I'm gonna take the leap with the 280xfi. Worst case might need raise converter stall a bit more.

 

The 280 will be fine then but I think I would entertain doing it on a 112 instead of the 110. Do you already have the Accel DFI?

 

Xfi comes in a 113. I would lean to 268 here. I rather see it on a 110-111 lsa

 

Yes I have the Accel DFI already.

 

Cam is getting ordered next week. Still might go with your suggestion of a XFI custom grind on a 224/230 between the 268 and 280 grinds.

 

They have lobes in 2 deg increments lol. Could do anything in between
218/224 220/226 222/228 224/230 226/232

 

Let me know if you need any help there.
And I'd still lean towards the wider lobe sep. The Supperram will make the midrange tq anyway, I'd try to stretch it a bit.

And the DFI will be fine with virtually any cam so get what is best for the combo, not because it'll have EFI.

 

Not sure if either of these are of interest esp the schneider cam !
https://www.thirdgen.org/forums/engi...ement-cam.html

 

Comp cam 224/230 XFI lobes ordered. Porting the Edelbrock base on the superram and 5 angle valve job and bowl work on the trick flows. Going to do a baseline pull on the flat tappet setup with the Accel system next week to see what increase we get from the roller and the port work. Will post baseline dyno sheet when I get it.

 

Subbed will be looking for the dyno sheet!

 

Heads are assembled after valve job, bowl work and new springs.

 

Comp XFI 224/230 on 110 LSA installed heads and intake are on and hitting the dyno tomorrow morning. Looking for 350+ at the wheels.

 

Get it on vid! How ported in the superram? I have almost this same setup I'm putting together and can't wait to see how yours runs! And vids on the car?

 

Uhhggg.......initial noise on the dyno spool up. Shut it down pulled plugs and put a scope in the cylinders. Rear cylinder scored and piston is cracked New GM Performance parts ZZ 350 short block on the way from Summit, will be here Monday. The block in there now is a Blueprint cheapo 355 short block the new ZZ 350 has a forged crank etc. AF and timing were WAY conservative on the initial pull. Will post results and pics of failure. Bizarre .

 

Hmm wonder what caused failure? Zz has forged crank but still powdered rods and either cast or hyper pistons

 

Changed order. New Gm parts ZZ 383 short block plus a Comp XFI 280 cam on a 110 lsa. Should be a good power jump from the 350.

 

That sucks, can't wait 4 results.

 

What are the results on the run or runs you did get to do? I'm interested in this cam

 

Finally got the car out to the track with the new 383 Superram. Ran 12.3 @113. Converter slip is pretty bad. Really losing a lot through it. By the 5th run I broke something in the tranny (something rattling around). Time for a new tranny and better converter. Getting tired of putting money in the IROC. I go out to the track with my 2013 CTS-V and rip off an 11.1@126 like I was sitting in a living room and nothing breaks or gives me problems. Love the IROC but it may be time to stop tracking it and just street cruise unless I want to drop a 12 bolt rear etc into it.

 

Well, a lot has changed since the 3rds were built. They were made with 250hp max HP in mind and these newer cars are made for waaaaaaay more than that.

Don't give up, it's a long road but great when you get it lined out..

 

New trans and converter will def improve that combo but dont expect it to compete with a factory blower car lol

 

Lol, I don't expect it to come anywhere near a modded CTS-V. But a converter and trans should get me to a 11.80-11.90 with a Superram 280xfi 110 lsa 11:1 compression 383. Problem is if I go to a good high stall converter it will shock the 10 bolt rear and break that next.......guess its just money and time.

 

It could live for awhile. You'd be surprised. It definately should get into the 11's

 

Btw, the 280xfi takes the unported Superram to peak power at 5900rpm. Most say it peaks at 5500. Guess a good cam makes a difference.

 

Yeah its gonna change the curve abit. Once tuned you'll need to play with shift points to find optimal times

 

Have any vids!? Hows the mid range power with that size cam and superram

 

So I can't believe it......that rattle noise wasn't the tranny. The brand new GM performance parts ZZ 383 lost a bearing and is rod knocking. Filter is full bearing material. Shop called GM parts and they will warranty the block plus the labor. I'm not having any luck with this car this year.......

 

What filters are you using?