dissapointing head flow numbers
05-25-2005, 06:57 AM
#21
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Just as Brent says -- many shops have specific valve jobs for specific heads, so without that specific valve job the heads just won't flow. Same goes for the valve itself. The width of the seat angle and backcut angle make a tremendous difference. It can even cause your port to go turbulent and back up even though the original angle would never back up. Not to mention the fact that LSX heads are a tricky bitch to begin with.
Your best bet is to call MTI and speak with them directly about those heads/valves/etc. Or send them to another shop that does a lot of LS1 work.
Your best bet is to call MTI and speak with them directly about those heads/valves/etc. Or send them to another shop that does a lot of LS1 work.
05-25-2005, 08:41 AM
#22
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CHS does a lot of LS1 heads so he is going to give it another valve job. He already has the heads so I can't check them over right now. Thanks for the input guys!
05-25-2005, 12:17 PM
#25
Not to be a ***, but you really seem like you have taken the wrong steps here.
MTI as most know do very good work. They have and have had a top notch rep for years.
If you bought these heads used how did you ask MTI for 2.055 valves? If used the valves were already assembled in the heads and would be impossible to ask MTI to switch them since your not even dealing with them.
You do however say they were refreshened 200 miles ago. By who? If MTI refreshened them and you asked for a 2.05 valve during that time and you paid for it but didn't recieve them I would defentially send them back and ask why I paid for something I didn't recieve.
Listen to what Brent said a couple posts above.
This is very important advice.
Sorry to bash a little, just trying to clear some thiungs up.
As far as your origional question.
Those flow numbers are pretty good for that casting head.
Not the best but still good.
MTI as most know do very good work. They have and have had a top notch rep for years.
If you bought these heads used how did you ask MTI for 2.055 valves? If used the valves were already assembled in the heads and would be impossible to ask MTI to switch them since your not even dealing with them.
You do however say they were refreshened 200 miles ago. By who? If MTI refreshened them and you asked for a 2.05 valve during that time and you paid for it but didn't recieve them I would defentially send them back and ask why I paid for something I didn't recieve.
Listen to what Brent said a couple posts above.
This is very important advice.
Sorry to bash a little, just trying to clear some thiungs up.
As far as your origional question.
Those flow numbers are pretty good for that casting head.
Not the best but still good.
05-25-2005, 01:08 PM
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fellas, keep your panties on. The heads were sent out over a week ago to have the valves changed because my tool will not fit the manley dual springs. So yesterday I get an email telling me what my flow numbers are. They were less than I expected and I made a post about. Once I get the heads back, if they still seem unsatisfactory, I will call MTI. I bought these used that had a refresh with zero miles. it was not done by MTI.
Does this make sense?
Does this make sense?
05-25-2005, 02:09 PM
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Originally Posted by JZ'sTA
Tighty whities for me.
J/K.
I am still confused why you call out MTI for not having the 2.05 valves you asked for.
That dosen't make since.
thats like me asking Wendy's for a Big Mack and being made I got a doubble stack.
J/K.
I am still confused why you call out MTI for not having the 2.05 valves you asked for.
That dosen't make since.
thats like me asking Wendy's for a Big Mack and being made I got a doubble stack.
****, I rephrased my thread title even. So the heads started out as MTI's and some other shop must have fubarred them. My numbers are less than expected. Sorry everyone for me being dissapointed. Not bashing MTI because I had no idea that someone else doing the valves could mess this up. Sorry for me being a total ******* retard and not knowing ****.
05-25-2005, 02:44 PM
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I'm having a set of MTI Stage 2R heads flow tested tomorrow and should have results by Friday. Likewise, I'm havng my AFR's tested at the same time so we can do a little comparing. Both are new. And Derek I don't blame you for not contacting MTI at least until you get your heads back. Holy shiot guys I realize you like the MTI's but lets not let it cloud what he was asking in this thread. He does NOT have the heads right now so no calling MTI would be basically a waste of time, the valves were being replaced so the ones MTI sent to do the replacement were the wrong ones, not the ones that are currently in the heads, and on top of that he just asked what you guys opinion was about his flow numbers. Sometimes I think our loyalty to manufacturers makes us more defensive than productive when helping out members on the boards.
05-25-2005, 03:59 PM
#33
well, hold up here.
MTI did the port job. I understood what Derek explained from the beginning. Someone redid the valve-job and obviously they flow differently than what MTI set up. I don't think this fellow was bashing MTI, and while I realize that sometimes we get overprotective of MTI, this *was* going a little far on acting like they can do no wrong. Recently I asked for a flow sheet of my Stage 3 MTI heads, and I got a nice flow sheet. I was pretty excited until I realized that I got the sheet that was posted on the MTI website. Now.... maybe they put my flow sheet up as the banner... but since they were thrice reworked ARE heads that had been reworked by ARE a couple times, I *kinda doubt* I have banner results. I didnt expect them. Because I dont believe what I got, I'll be flowing the heads when I take them off in a few days. Will I be angry if they dont flow well? Not at MTI... they had nothing but some hogged out ARE's to work with.
The fellow was asking if he should be disappointed in his flow numbers... and my answer is:
What is the volume of the port?
MTI did the port job. I understood what Derek explained from the beginning. Someone redid the valve-job and obviously they flow differently than what MTI set up. I don't think this fellow was bashing MTI, and while I realize that sometimes we get overprotective of MTI, this *was* going a little far on acting like they can do no wrong. Recently I asked for a flow sheet of my Stage 3 MTI heads, and I got a nice flow sheet. I was pretty excited until I realized that I got the sheet that was posted on the MTI website. Now.... maybe they put my flow sheet up as the banner... but since they were thrice reworked ARE heads that had been reworked by ARE a couple times, I *kinda doubt* I have banner results. I didnt expect them. Because I dont believe what I got, I'll be flowing the heads when I take them off in a few days. Will I be angry if they dont flow well? Not at MTI... they had nothing but some hogged out ARE's to work with.
The fellow was asking if he should be disappointed in his flow numbers... and my answer is:
What is the volume of the port?
05-25-2005, 04:17 PM
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I can tell you the heads are milled .030. Not sure what the port volume is to begin with.
I have a copy of the original purchasers receipt. It shows a part # of 98PTHD2
I have a copy of the original purchasers receipt. It shows a part # of 98PTHD2
05-25-2005, 04:45 PM
#35
Honetly, who cares what the heads flow on a bench. Each bench may have a slight variation due to setup, radiused inlet vs intake, Pipe vs no pipe. The valvejob is very important, probably one of the most important parts of how a head flows aside from the bowl, you can see a 10-20cfm variance due to the valvejob. Put the heads on and run the car.
Phil
Phil
05-25-2005, 04:50 PM
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Originally Posted by Derek98z
All I said was I ordered 2.055 replacement valves and they sent me 2.02's. It sets me back some time, that's all and that it's a hassle
****, I rephrased my thread title even. So the heads started out as MTI's and some other shop must have fubarred them. My numbers are less than expected. Sorry everyone for me being dissapointed. Not bashing MTI because I had no idea that someone else doing the valves could mess this up. Sorry for me being a total ******* retard and not knowing ****.
****, I rephrased my thread title even. So the heads started out as MTI's and some other shop must have fubarred them. My numbers are less than expected. Sorry everyone for me being dissapointed. Not bashing MTI because I had no idea that someone else doing the valves could mess this up. Sorry for me being a total ******* retard and not knowing ****.
Brandon
05-27-2005, 02:40 PM
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First of all I'd like to say that I've just joined this forum in hopes that I can add some input you can all use. My reasoning in my comments comes from thousands of hours of cyl. head R&D and back to back dyno testing of these changes. also note that as this is an LS1 tech forum all motors follow the same principals for making h.p., they're simply an air pump and the writing on the valve cover doesn't change how the motor functions. One of the most important aspects of a cyl. head is port size, The only reason there is any benefit what so ever to enlarging your int port is if it gains you airflow in the areas that restrict you engine, and that's usually at the higher rpm's where the airflow need increases. In 10 years of flogging the Yates head for winston cup what do you think was the 2 key ingredients in making more power ? shrinking the int. port and increasing low and mid lift airflow. When the yates head was introduced in late "89" we then were making approx 675 h.p. with 358 cubes with airflow peaking at 370 cfm @.700 lift and a runner size of 265 c.c's, After 10 years and at least 15 major changes our big port for the high rpm tracks was down to 229 c.c's and flow peaked at .365 at .600 lift and went turbulant after that and flow dropped to approx 352 at .700. and the flow from .150 to .400 was up huge, we now were making close to 750 h.p. and we were spinning up to 9400 rpm. with cams slinging the valve open to near .750 lift. measured on the spintron. after seeing how high the valve was actually being tossed we tried again going back to the bigger airflow at higher lifts to accomodate the newer larger cams that we were now running. This is most interesting. most of the work was around the seat area and valve job with a total port volume increase of 4 c.c.'s. We gained airflow considerably past .550 lift flowing 385 at .750 lift, thats over 30 cfm at peak cam lift, but unfortunatly the correct look for high lift flow can't be the correct look for low and mid lift flow and so comes the penalty at .150 to .400. . We lost 6-7 cfm at .200-.300 lift and aprrox 5 cfm @ .400 lift with the flow being even at .500. What do you think happened ? the motor lost approx 15 H.P. from 4000 to 8800 and only came back even at 9300 rpm. Without rambling on any further, if the public saw 2 flow sheets side by side or 2 advertised heads with one flowing 365 and falling off after .600 lift and one screaming out that big 385 cfm all the way to .750 what head would they choose everytime? thought so !!! especially if they planned on making 750 H.P. with 358 cubes. Also when we used these same heads ( the ones the peaked at .600 lift ) and ran them on a pro stock style motor with a tunnel ram and a .900 lift rollar cam we made over 900 H.P. still with just 358 cubic inches. So think about the next time you see LS1 style heads with huge flow numbers up to .700 lift and then think about the cam you'll be using, where your low and midlift point is then seriosuly consider how much flow you really need. Bigger is better went out years ago but unfortunatly still lives in the advertising world, spend your money wisely !
05-27-2005, 04:23 PM
#40
Originally Posted by Tucunare
First of all I'd like to say that I've just joined this forum in hopes that I can add some input you can all use. My reasoning in my comments comes from thousands of hours of cyl. head R&D and back to back dyno testing of these changes. also note that as this is an LS1 tech forum all motors follow the same principals for making h.p., they're simply an air pump and the writing on the valve cover doesn't change how the motor functions. One of the most important aspects of a cyl. head is port size, The only reason there is any benefit what so ever to enlarging your int port is if it gains you airflow in the areas that restrict you engine, and that's usually at the higher rpm's where the airflow need increases. In 10 years of flogging the Yates head for winston cup what do you think was the 2 key ingredients in making more power ? shrinking the int. port and increasing low and mid lift airflow. When the yates head was introduced in late "89" we then were making approx 675 h.p. with 358 cubes with airflow peaking at 370 cfm @.700 lift and a runner size of 265 c.c's, After 10 years and at least 15 major changes our big port for the high rpm tracks was down to 229 c.c's and flow peaked at .365 at .600 lift and went turbulant after that and flow dropped to approx 352 at .700. and the flow from .150 to .400 was up huge, we now were making close to 750 h.p. and we were spinning up to 9400 rpm. with cams slinging the valve open to near .750 lift. measured on the spintron. after seeing how high the valve was actually being tossed we tried again going back to the bigger airflow at higher lifts to accomodate the newer larger cams that we were now running. This is most interesting. most of the work was around the seat area and valve job with a total port volume increase of 4 c.c.'s. We gained airflow considerably past .550 lift flowing 385 at .750 lift, thats over 30 cfm at peak cam lift, but unfortunatly the correct look for high lift flow can't be the correct look for low and mid lift flow and so comes the penalty at .150 to .400. . We lost 6-7 cfm at .200-.300 lift and aprrox 5 cfm @ .400 lift with the flow being even at .500. What do you think happened ? the motor lost approx 15 H.P. from 4000 to 8800 and only came back even at 9300 rpm. Without rambling on any further, if the public saw 2 flow sheets side by side or 2 advertised heads with one flowing 365 and falling off after .600 lift and one screaming out that big 385 cfm all the way to .750 what head would they choose everytime? thought so !!! especially if they planned on making 750 H.P. with 358 cubes. Also when we used these same heads ( the ones the peaked at .600 lift ) and ran them on a pro stock style motor with a tunnel ram and a .900 lift rollar cam we made over 900 H.P. still with just 358 cubic inches. So think about the next time you see LS1 style heads with huge flow numbers up to .700 lift and then think about the cam you'll be using, where your low and midlift point is then seriosuly consider how much flow you really need. Bigger is better went out years ago but unfortunatly still lives in the advertising world, spend your money wisely !
Bruce