454 with 177 blower build
03-16-2015 | 10:12 AM
#142
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From: Newark, DE
As far as comparing the numbers on those builds, marks setup made 691HP at 6000, , and 666FT lbs , at 3800RPM. with 4.2psi. Ealeshs made 670HP at 6000, and 662FT lbs at 3800, with 5.6psi, and 636HP at 6000, with 3.5psi, and 617FT lbs, at 3800rpm. So, with 1psi less, ealesh's made 55HP less, and 47ft lbs less. With 1.5psi MORE than marks, it made 21HP less, and 4 ft lbs less at 3800.
Both engines had very similar cams from what I recall, very similar compression, same blower, main difference is one had 265 oval heads with oval intake, one had 305 heads, with rect ports. While this comparison isnt the most accurate information, I still have yet to see, where the small ovals did anything better, on a roots blower build, than a decently sized set of rectangles. The 40cc larger low velocity intake runner, surely didnt hurt torque output in the midrange. Heck marks was making 656ft lbs at 3500.
While , not a fair comparison, since they were on two different dynos, I do appreciate the info on the builds. For the longest time now, I've been "told", about the optimum port size for NA is optimium for blower, how much HP a certain head can support, how the larger heads would hurt low end and midrange, and all kinds of stuff without data. I've been told Im flat out wrong, stupid (yes, in pm's) and so forth regarding these small ci blower builds. Mike T and I are certainly no experts, but we arent also new to these types of builds.
Comparing numbers from dyno sheets are hard to do, when dealing with separate dyno's, different boost levels, air fuel ratios, etc. I think both of these engines made great power for what they are, so really, its a win for everyone, as long as the builds stay together.
Both engines had very similar cams from what I recall, very similar compression, same blower, main difference is one had 265 oval heads with oval intake, one had 305 heads, with rect ports. While this comparison isnt the most accurate information, I still have yet to see, where the small ovals did anything better, on a roots blower build, than a decently sized set of rectangles. The 40cc larger low velocity intake runner, surely didnt hurt torque output in the midrange. Heck marks was making 656ft lbs at 3500.
While , not a fair comparison, since they were on two different dynos, I do appreciate the info on the builds. For the longest time now, I've been "told", about the optimum port size for NA is optimium for blower, how much HP a certain head can support, how the larger heads would hurt low end and midrange, and all kinds of stuff without data. I've been told Im flat out wrong, stupid (yes, in pm's) and so forth regarding these small ci blower builds. Mike T and I are certainly no experts, but we arent also new to these types of builds.
Comparing numbers from dyno sheets are hard to do, when dealing with separate dyno's, different boost levels, air fuel ratios, etc. I think both of these engines made great power for what they are, so really, its a win for everyone, as long as the builds stay together.
03-16-2015 | 10:16 AM
#143
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From: Newark, DE
Well, not some marine log manifolds. Lol.
I know what your asking though. What diameter primary tubes, how long, etc. I believe mikes shops BBC dyno headers are 2 1/8 primary. I don't know what eleash shop had, but they didn't look small.
I haven't found forced induction engines nearly as sensitive to exhaust "tuning" as NA, but I haven't much data to support that. Generally I've seen blown stuff simply like a non restrictive big pipe stuff. Like stellings steroid headers, stainless marine gen 3 with 5" diameter elbows and tails, etc.
I know what your asking though. What diameter primary tubes, how long, etc. I believe mikes shops BBC dyno headers are 2 1/8 primary. I don't know what eleash shop had, but they didn't look small.
I haven't found forced induction engines nearly as sensitive to exhaust "tuning" as NA, but I haven't much data to support that. Generally I've seen blown stuff simply like a non restrictive big pipe stuff. Like stellings steroid headers, stainless marine gen 3 with 5" diameter elbows and tails, etc.
03-16-2015 | 10:19 AM
#144
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From: Newark, DE
03-16-2015 | 10:30 AM
#146
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From: Newark, DE
Another difference is I saw Mike dyno'd at 36 degrees timing where we did at 34 degrees. We dropped timing back to 33 so see if with the combustion chamber being more efficient it liked less timing better, it didn't the change was about 2-3hp going from 34 back to 33. I'm not sure if there is any gain or not going up, 34 could be the sweet spot but don't know for sure. Mike did you play with timing under that 36 degrees you used?
03-16-2015 | 10:43 AM
#147
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From: On A Dirt Floor
I'll study those later, thanks Ealash....one thing that stood out at me doing a super quick glance is, believe it or not, was your engine could definately use more carb cfm. And some people are afraid of Dominators for some reason. And there yours was, wanting to be even bigger. LOL.
03-16-2015 | 11:01 AM
#149
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From: On A Dirt Floor
03-16-2015 | 11:07 AM
#150
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From: Chicago
You don't support what your saying with anything, you just say it. What makes what you are saying right over the next guy? This is the problem, I ask you a simple question cause I don't know you or most on here from Adam, You just come back with sarcastic smart ass comments, and really add nothing technical to the conversation.
The manufacturer says the MAX RPM is 15, 000. The rest is just common knowledge. I know hot air rises and electricity follows the path of least resistance but no I haven never tested it personally.
Like I said you know best, you don`t take advice . You left a bunch of power on the table because you said 305 was too big, you proved it wasn`t.
I was just trying to give you some advice because I saw those AFR numbers along with the speed of the blower and timing on the dyno which were alarming.
Obviously you know best and you trust your builder. End of story, end of discussion
Last edited by ICDEDPPL; 03-16-2015 at 11:09 AM.
