I would like to ask what cam specs are being used for 582 and 598 bracket engines set up for TBS 250 blowers. I have checked around for recommendations and there is a big difference in what was recommended.

Pick a cam grinder that you prefer, give the your engine specs and be detailed. Install the cam they provide where they say to install it and run it. Every engine is different, there is no set "spec" for an engine with a 250 blower. Someone can have the same engine size but due to some of the parts it might have, will require a different cam because of those parts.

I will preface by saying this is the same cam that was in the motor prior to adding the TBS 250. Motor is a 598 with same AFR 357 heads and the cam is a LSM .875/.833 282/296 with 1.75/1.70 rockers. Compression is at 13.5 and timing at 26*.

Yep same cam before and after the 250. Pick one that will make good natural power and you should be good.

285/302 850/830 113 LSA, made 1030 NA on 598, never been to dyno with the 250 but car went best of 4.75 @ 145 NA, and has been 4.32 162 with 250. 2100 lb with driver, 4 link dragster.

You'll make 8-10 psi on good days, more than likely you'll be in the 3-5 psi range for bad weather days.

Same cam in our 540 as when it was NA...don't have the card in front of me but similar to Triple Nickles, but our exhaust has less lift and duration.

Very happy with the combination, it's been 6.80/199 - 4.35/161 with a 31 pulley. Going to try the 29 later this year....

Weekly bracket racing we run a 35 pulley and it goes 7 teens and 4.50s very consistently.

quote:

Originally posted by Dragordie:
I would like to ask what cam specs are being used for 582 and 598 bracket engines set up for TBS 250 blowers. I have checked around for recommendations and there is a big difference in what was recommended.

I may get some flak for my input, but if you already have a known good cam that works well now NA I would use it.

I have a aluminum 5.3 ls with a 250 blower shop on it that was originally NA for 2 seasons-same camshaft, a 383 with 192 blower shop for my sons truck we are building-new camshaft, but I have knowledge of running this camshaft spec in other engines before, and my dragster with 582 F1R ProCharger has the same camshaft as it did when it was NA. Small camshaft in the .740 range and has been 4.10 so far in the 1/8. This camshaft had been a best of 4.55 in this 582 NA years ago and I just stayed with it as I knew it was the quickest camshaft for me in this engine I had tried over the years in it. Think I had tried 6 total in it.

If you're not putting the blower on for max effort ET and speed, but to merely "bring your own atmosphere" for bracket racing consistency, (a good plan in my opinion) I'd not bother to change anything of your N/A combo, except appropriate tune adjustments.

Engine Master did dyno test on blower cams. Yes agree it still TV.
They basicallyh found cam does same thing with blower as it did NA. Meaning same power curve same peak points.

I habve always went with at most you need more exhaust flow . More oiut because more coming under pressure. Should be filling cylinder and have more to get out. Same pressure pushing out as NA plus little due to amount burned.

At same time you may need to reduce overlap since less needed scavaging effect.

Do not get stupid with exhuast that does not work, I have cam on shelf to prove it too.LOL In my defence cams use to be 300 to 400 buck and cheap experiment in the big picture.

If I was doing same deal I would consult with someone who is damn good at designing cams and not selling them. Brian Salter here in NC I think WInston Salem seems smart as hell on cams . He has You tube channel and deals with some big name folks. Worth phone call. Google Salter engine or racing. Dude has ton of championships in lots of forms of racing.

This message has been edited. Last edited by: wideopen231,

I’m just here to note that these 250 blower times listed are stout. I’ve seen a lot of them not run nearly that well

Bucky,

The guys that have aluminum blocks are even more impressive. Only challenge I've seen with the 250 is it falls off pretty bad when the weather is 100F and track temps through the roof. We see high 4.40s to low 4.30s change from dead heat summer to cool winter/fall weather. 67/31 pulleys on this one.

I've heard of guys cutting 3" wide 8MM 70+ tooth pulleys down to 2" wide and running those. The 250 blowers are impressive given the size of them.

AS others have said, if the base power is good, adding a 250 just makes it better.

My junk is not as fast as these others! I am typically a mid 4.50 car at 2175lbs. Best it has been was 4.47@156 with a 10” converter that was brutal on the tire for the first .8 seconds and then ran good after that. That was with a 33/67 pulley setup in killer air. I am currently running a loose 9” and 31/67 in the thick wet air we have right now. GOW is what seems to slow mine down the most and track temp. Let the sun get below the trees and it’s going to pick up .02 normally.

70 Mach 1, we've been on a 10+ year old Transmission Specialties 10", they ran out of business a few years back so ATI did the last freshen up and loosen up, like you said it can be brutal in the first 60 if you not paying attention. I did try an Abruzzi 9" early on in the game slowed the car nearly a tenth and 4 mph. Like you when the sun goes down it usually picks up some, when track temp goes down at night in summer time all of my combos typically do the same.

I am currently running a FTI 93bc. It’s very consistent but this weekend later at night it was flashing 6800+ dropping 550-600 at the shift and crossing at 7550-7600 at 154.5. I am actually changing fluid for this weekend from my normal transynd 668 to some redline type f that’s supposed to be a little heavier to try and tighten it up 100 rpm. I prefer to keep it under 7500

quote:

Originally posted by 70 Mach 1:
I am currently running a FTI 93bc. It’s very consistent but this weekend later at night it was flashing 6800+ dropping 550-600 at the shift and crossing at 7550-7600 at 154.5. I am actually changing fluid for this weekend from my normal transynd 668 to some redline type f that’s supposed to be a little heavier to try and tighten it up 100 rpm. I prefer to keep it under 7500

I tried the heavier fluid twice, once NA and once with the blower and it did nothing. Curious if you get a different result.

I think the 250 blower is relatively small so it does not create the boost as some of larger blowers. More forgiving on cam specs. Call Bullet and talk to them, they are experts and can tell you what is optimum and if your existing cam would work well enough.

I’ll report back this weekend, but it won’t be a good back to back comparison. We will be at Texas Motorplex and the air is going to be worse this weekend and next. I’ll compare other same mph runs with what it does this weekend.

I compared a few runs where the mph is within .1 and it looks like the trans fluid tightened the converter between 50-70 rpm. I’ll be able to do a better comparison next time I am at my home track.

quote:

Originally posted by 70 Mach 1:
I’ll report back this weekend, but it won’t be a good back to back comparison. We will be at Texas Motorplex and the air is going to be worse this weekend and next. I’ll compare other same mph runs with what it does this weekend.

Good Luck at Texas Motorplex.

Same cam here on my junk as I was running before 582BBC. I have seen some guys use a big core camshaft but I dont see a need for it at this time.

Thanks Bruce, got my teeth kicked in last weekend, hoping for a better showing this weekend.