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by hoffman900
Tue Jan 18, 2022 9:27 pm
Forum: Engine Tech
Topic: 1 5/8” headers and 500hp?
Replies: 86
Views: 7098

Re: 1 5/8” headers and 500hp?

If the exhaust gasket dimensions (Felpro 1487, 1.62 x 1.42) are a good indicator of the exhaust port dimensions for a 210cc Victor Jr, I would think that the port mismatch might be a larger issue than the flow of 1 5/8 headers. I've had difficulties with finding 1 5/8 headers that had large enough ...
by hoffman900
Tue Jan 18, 2022 9:10 am
Forum: Engine Tech
Topic: 1 5/8” headers and 500hp?
Replies: 86
Views: 7098

Re: 1 5/8” headers and 500hp?

Heres a quote from Calvin regarding his approach to header construction. 1) Stepping tube sizes is to me essentially a flow issue. I never hold a tube diameter more than 12", unless it is already larger than it needs to be for the given power level. Stepping tube diameters also introduces an area c...
by hoffman900
Mon Jan 17, 2022 10:06 am
Forum: Engine Tech
Topic: 1 5/8” headers and 500hp?
Replies: 86
Views: 7098

Re: 1 5/8” headers and 500hp?

Should one assume theres a linear relationship between pipe size and HP? Calvins 1.625" pipe support 73.7 HP Assuming linear relation a 1.375" would support 52.9 HP? I also assume that figure from Calvin is for a straight and/or big radius bend pipe? I’ve seen 1.375” off the head to the first step ...
by hoffman900
Mon Jan 17, 2022 9:39 am
Forum: Engine Tech
Topic: 1 5/8” headers and 500hp?
Replies: 86
Views: 7098

Re: 1 5/8” headers and 500hp?

Should one assume theres a linear relationship between pipe size and HP? Calvins 1.625" pipe support 73.7 HP Assuming linear relation a 1.375" would support 52.9 HP? I also assume that figure from Calvin is for a straight and/or big radius bend pipe? I’ve seen 1.375” off the head to the first step ...
by hoffman900
Sat Jan 15, 2022 2:01 pm
Forum: Engine Tech
Topic: Cam design basics ?
Replies: 90
Views: 23423

Re: Cam design basics ?

CamKing wrote: Sat Jan 15, 2022 1:57 pm
hoffman900 wrote: Sat Jan 15, 2022 12:31 pm I forgot you had mentioned the rollers are really just LARGE diameter flat tappets design wise.
Other way around.
From the design standpoint
A flat tappet profile is just a roller profile with a 56" radius roller.
Ah, yes.
by hoffman900
Sat Jan 15, 2022 12:31 pm
Forum: Engine Tech
Topic: Cam design basics ?
Replies: 90
Views: 23423

Re: Cam design basics ?

Thanks Mike. As a follow up to this post I have another question. The last few years, I’ve had stuff come through the shop that in m opinion had ports with too much cross section. It’s easy to do today, especially since everyone buys heads base on flow. The question is I think the same thing can be...
by hoffman900
Sat Jan 15, 2022 11:43 am
Forum: Engine Tech
Topic: Bullet/Ultradyne Cams
Replies: 10
Views: 658

Re: Bullet/Ultradyne Cams

Lunati has "some" but, Bullet has "all" of the Ultra-Dyne profiles. Bullet also bought the rights to the Lazer profiles when Bill Metzger died. and Howards has all the Arrington era Brookshire stuff as CNC ground profiles. Curious what condition some of those 40yo masters are like at Bullet in that...
by hoffman900
Sat Jan 15, 2022 11:08 am
Forum: Engine Tech
Topic: Bullet/Ultradyne Cams
Replies: 10
Views: 658

Re: Bullet/Ultradyne Cams

You are mis interpetating "better" as being solely a shorter seat duration VS .050" duration and or a bigger .200" duration VS .050" duration. Making the cam lift curve more and more intense has mechanical costs. More spring force / rpm More pushrod/ rocker deflection. Faster cam/lifter/rocker arm ...
by hoffman900
Sat Jan 15, 2022 9:32 am
Forum: Engine Tech
Topic: Bullet/Ultradyne Cams
Replies: 10
Views: 658

Re: Bullet/Ultradyne Cams

Yes you can get a Ultradyne cam from Bullet Racing Cams. Nothing obsolete about these. Lunati shows these cams as "New". "Street strip" and "new oval" solids etc. You can find the lobe master specs in the Lunati lobe lists. You can get the off the shelf catalog grinds and any combo and lobe separat...
by hoffman900
Fri Jan 14, 2022 11:06 pm
Forum: Engine Tech
Topic: Cam design basics ?
Replies: 90
Views: 23423

Re: Cam design basics ?

You're not going to believe it, but that 1994 engine that Honda developed, used a cast iron block. Yep, I worked on that engine. It was a real drain to moral for the project. One of my tasks there was fitting plated aluminum sleeves to those blocks, (nicest turning equipment I ever used, you could ...
by hoffman900
Fri Jan 14, 2022 8:03 pm
Forum: Engine Tech
Topic: Bullet/Ultradyne Cams
Replies: 10
Views: 658

Re: Bullet/Ultradyne Cams

Howards has most of the designs Harold did after Ultradyne (during his time at Custom Camshaft Company (Arrington)). Lunati has his last commercially available designs. The Howards’ Harold’s stuff are all CNC profiles so it would just be a matter of loading it in the machine. You can see them here: ...
by hoffman900
Fri Jan 14, 2022 6:59 pm
Forum: Engine Tech
Topic: Cam design basics ?
Replies: 90
Views: 23423

Re: Cam design basics ?

Stage II Buick V6, my 2 cents. Indy development was likely too rushed to have a proven alum. block in time. These came later for IMSA GTP. I have heard, the iron blocks were acid dipped, for Indy. For a while, those heads reined as the best inline 2 valve,( even put on the sbc.) Who knows, they mig...
by hoffman900
Fri Jan 14, 2022 4:54 pm
Forum: Engine Tech
Topic: Cam design basics ?
Replies: 90
Views: 23423

Re: Cam design basics ?

Yikes! I guess with the Buick, if you made an aluminum block it wouldn’t be production anymore, Actually, there was nothing in the rules about the block material having to be stock. When my dad build the 209ci turbo Chevy V8's for indy, in the early 80's, he had Chevy cast the blocks out of Aluminu...
by hoffman900
Fri Jan 14, 2022 3:07 pm
Forum: Engine Tech
Topic: Cam design basics ?
Replies: 90
Views: 23423

Re: Cam design basics ?

No, the 1994 engine when Rahal had to buy a Ilmor-Chevy Penske car to qualify for the Indy 500. You're not going to believe it, but that 1994 engine that Honda developed, used a cast iron block. That added weight made those chassis that were designed around the all aluminum Cosworth, impossible to ...
by hoffman900
Fri Jan 14, 2022 1:52 pm
Forum: Engine Tech
Topic: Cam design basics ?
Replies: 90
Views: 23423

Re: Cam design basics ?

Since you were there, what did Honda first mess up with their foray into Indy Cars in the mid 1990s? Are you talking about the Judd-Honda that debuted in 1988 ? That engine was designed and Built by Judd, and Honda just put their name on it. I never looked inside of one, but it was a new engine, tr...