Texas Speed Heads Question on Compression
Thread Starter
Joined: Apr 2008
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From: Eaton, Colorado
Texas Speed Heads Question on Compression To start, I am playing around with another LS1 build (Not looking to make anything crazy, want a great hot rod power tour car, that I can drive across the country).
Came across TSP Small Bore heads, and it gives options on combustion chamber sizing, understanding that stock ls1 241 heads are between 67-68cc and that puts overall engine compression around 10.1-1. What size combustion chamber would get me around the 11.1 range? I am sure there is a calculator out there I couldn't find, was hoping Texas Speed might chime in or some one who might know could throw out some numbers. I appreciate the help.
https://www.texas-speed.com/p-1163-p...der-heads.aspx
Came across TSP Small Bore heads, and it gives options on combustion chamber sizing, understanding that stock ls1 241 heads are between 67-68cc and that puts overall engine compression around 10.1-1. What size combustion chamber would get me around the 11.1 range? I am sure there is a calculator out there I couldn't find, was hoping Texas Speed might chime in or some one who might know could throw out some numbers. I appreciate the help.
https://www.texas-speed.com/p-1163-p...der-heads.aspx
Last edited by 99Ls1fever; Sep 27, 2021 at 01:56 PM.
241 heads are 71.5 cc and the LS1's were at 10:1 compression so you would have to mil the heads to 65cc in order to reach 10.9:1. You could take a set of 862's or 706's which are the small bore heads found on 5.3's and have smaller valves but also have smaller 61.5cc combustion chambers and that will get you 11.4:1 so taking a set of 862/706 heads and having them cnc'd with the larger valves installed is one way to go albeit more expensive than milling your 241's.
Thread Starter
Joined: Apr 2008
Posts: 1,822
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From: Eaton, Colorado
Appreciate the feedback, I have no plans on milling my stock LS1 241 heads. My intentions are to get a pair of TSP 227's, and since there is no charge on different combustion chamber sizing, I could get a nice set of heads that flow better than the 241's and increase my engine compression from 10.1 to 11.1-3 range and pick up some additional power through the raise in compression.
Kind of looks like 62cc might be the ticket
Kind of looks like 62cc might be the ticket
Appreciate the feedback, I have no plans on milling my stock LS1 241 heads. My intentions are to get a pair of TSP 227's, and since there is no charge on different combustion chamber sizing, I could get a nice set of heads that flow better than the 241's and increase my engine compression from 10.1 to 11.1-3 range and pick up some additional power through the raise in compression.
Kind of looks like 62cc might be the ticket
Kind of looks like 62cc might be the ticket
Thread Starter
Joined: Apr 2008
Posts: 1,822
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From: Eaton, Colorado
BTR Stage 3 (231/244 .630"/.615") https://briantooleyracing.com/btr-ca...3.html#reviews
I saw you mentioned the MSD Atomic, how do you like that intake?
I have run a camshaft similar in size to the MS4 before, I wasn't super happy with the high lift and stress it put on my valvetrain, when high revving (Drag Racing) 6500-7000rpm I seemed to have valve float and piston slap along with broken springs occasionally. It was a great dyno camshaft for me and made good power. But i was thinking a little milder like a BTR Stage 3, I have wanted to try his cams since he came out years ago but wasn't building any LS stuff at that time. I know some might say this is still a large cam, but I like the lift and duration.
BTR Stage 3 (231/244 .630"/.615") https://briantooleyracing.com/btr-ca...3.html#reviews
I saw you mentioned the MSD Atomic, how do you like that intake?
BTR Stage 3 (231/244 .630"/.615") https://briantooleyracing.com/btr-ca...3.html#reviews
I saw you mentioned the MSD Atomic, how do you like that intake?
I've made 600 rwhp with a n/a 416ci and prc 247cc cathedrals and a msd atomic in an fbody.
Thread Starter
Joined: Apr 2008
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From: Eaton, Colorado
you must have had bad springs or older comp ground cam that had more aggressive lobes. Pac .660 springs and a big cam with a good tuner will drive great. I do not like BTR Cams at all they never make good power on the dyno here . I run TSP cams or Summit cams.
I've made 600 rwhp with a n/a 416ci and prc 247cc cathedrals and a msd atomic in an fbody.
I've made 600 rwhp with a n/a 416ci and prc 247cc cathedrals and a msd atomic in an fbody.
If you dont mind me picking your brain a little, what about the BTR cams do you not like? Just the dyno numbers, or what specifically?
416ci making 600whp would be a pretty cool and fun car!
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I had early comp cams, TSP heads with the PAC springs and had alot of issues with springs and valvetrain control.
If you dont mind me picking your brain a little, what about the BTR cams do you not like? Just the dyno numbers, or what specifically?
416ci making 600whp would be a pretty cool and fun car!
If you dont mind me picking your brain a little, what about the BTR cams do you not like? Just the dyno numbers, or what specifically?
416ci making 600whp would be a pretty cool and fun car!
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Verdad Gallardo Thread Starter
Joined: Apr 2008
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From: Eaton, Colorado
They are always down on power va other companys cams. They say they grind them on super friendly lobes with soft ramp rates for 60+k mile spring life. Which is great If you want adequate power but a really really reliable cammed car. I don't ever want to build something average. And I've had amazing luck with summit and Tsp grinds. Next stop is a cam motion LLSR once I stop being a little baby about $1700 rockers arms lol
MS3 238/242 .600"/.600" 112.0
MS4 239/242 .649"/.600" 111.5
BTR 3 231/244 .630"/.615" 112.5
I see you are talking about the cam motion LLSR, I'll have to jump in and do some research on that, a few things have changed since last time I was building LS cars.
I was thinking about the our discussion on the TSP cams and the BTR 3 cam (Typical sleepless night), seems like it is a good in between on a MS3 and a MS4 camshaft on lift with less duration, one would think the dyno numbers who be close to in-between a MS3 and MS4 camshaft dyno/power number. Maybe I am off, I would think you would have similar power with more drivability with the smaller duration?
MS3 238/242 .600"/.600" 112.0
MS4 239/242 .649"/.600" 111.5
BTR 3 231/244 .630"/.615" 112.5
I see you are talking about the cam motion LLSR, I'll have to jump in and do some research on that, a few things have changed since last time I was building LS cars.
MS3 238/242 .600"/.600" 112.0
MS4 239/242 .649"/.600" 111.5
BTR 3 231/244 .630"/.615" 112.5
I see you are talking about the cam motion LLSR, I'll have to jump in and do some research on that, a few things have changed since last time I was building LS cars.
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
I think BTR has broken away from Comp grinding their cams, at least most of them from what I understand.
TSP, then BTR.... anyone see a pattern here?? Lingenfelter next? But their grinds are nearly prehistoric, so maybe not...
TSP, then BTR.... anyone see a pattern here?? Lingenfelter next? But their grinds are nearly prehistoric, so maybe not...
Thread Starter
Joined: Apr 2008
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From: Eaton, Colorado
Who would be your recommendation on camshafts?
Thread Starter
Joined: Apr 2008
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From: Eaton, Colorado
This camshaft seems very similar to the BTR 3 LS1 cam the specs are almost identical, but it talks about the quicker (More aggressive intake lobes) like you talked about Mavn. Again, another camshaft I haven't ran before or haven't been around in a car. Will have to do some archive digging and information gathering.
Mavn, I appreciate the heads up you have given on HP / dyno numbers, I am not saying that's everything, but a lot of archive digging has shown down on power numbers or cars peaking at 56-5800 rpms (given these were 2016 posts) but I haven't seen any post that I could find or research I could find that supports the 450hp that camshaft states with good heads and supporting mods.
Definitely still want my hot rod power tour cross country car, just want a little more power than 360hp, but don't want to sacrifice drivability.
https://www.texas-speed.com/p-1150-t...-camshaft.aspx
Mavn, I appreciate the heads up you have given on HP / dyno numbers, I am not saying that's everything, but a lot of archive digging has shown down on power numbers or cars peaking at 56-5800 rpms (given these were 2016 posts) but I haven't seen any post that I could find or research I could find that supports the 450hp that camshaft states with good heads and supporting mods.
Definitely still want my hot rod power tour cross country car, just want a little more power than 360hp, but don't want to sacrifice drivability.
https://www.texas-speed.com/p-1150-t...-camshaft.aspx
For off the shelf cams, and that criteria, I think a Cam Motion Titan IV or roughly similar ~ 228/232 type cam is worth thinking about. However that's a much too generic sort of cam for social media or cool factor heroics and a well done custom spec would probably be a bit better.
Cam Motion Titan IV
Grind # XA227/360-XA232/350-13+4
Hydraulic Roller Camshaft
Aggressive Performance
Duration at .050": 227/232
113 Lobe Center Angle with a 109 Intake Centerline
Lift with 1.7 Rocker Arm Ratio: .612"/.595"
Recommended Displacement: 5.3-6.2 Liter Engines
Cylinder Heads: Cathedral Port
Recommended Compression Ratio: 9.4.0-11.5:1
Well, according to Richard Holdener's testing the Sloppy stage 2 and the other stage 2 cams with similar duration are all within a couple hp of each other. So unless you are racing for a title or money, it probably doesn't matter than much.
Thread Starter
Joined: Apr 2008
Posts: 1,822
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From: Eaton, Colorado
Had a great call yesterday with Texas Speed in regard to drivability and performance, I do have emails in to Smallwood with completed form, and BTR. I really like the power and drivability options that they spoke about in the Torquer V4 Camshaft, they believe with the set of 243's I have if I sent them off to TEA to be CNC ported and milled down to 62cc raising the compression around 11.1-3 area pending on head gasket, with supporting mods (good intake) I would be between 450hp-480hp which if true along with great drivability would be 100% what I was wanting out of my original goal. Thanks to all of you for the advice and knowledge, I am waiting to hear back from the 2 companies mentioned above, and let everyone know what I find out.
Mavn- appreciate the discussion on TSP ramps vs BTR ramps that is definitely something I brought up and wanted better understanding of, so thanks for the input on that.
Mavn- appreciate the discussion on TSP ramps vs BTR ramps that is definitely something I brought up and wanted better understanding of, so thanks for the input on that.
Most of the guru benefit would probably be in tweaks like lobe selection for valve train longevity, how much advance to grind in and best LSA etc...and feeling like all the bases had been covered
