AFR 205s + big cam = 128mph
11-21-2005, 12:24 PM
#1
6600 rpm clutch dump of death Administrator
Thread Starter
AFR 205s + big cam = 128mph Well, I've been meaning to make one of my rather lengthy posts, but I've been really busy over the last few weeks. We've been playing around with the idea of swapping heads on Tommy's car to see if we could pick up some power.
The current LS6 casting were originally done by Jay @ Absolute Speed. Last year the heads dropped a seat, so the heads were taken over to Greg Good here in Houston. Greg replaced all the seats in the heads. Greg also commented that the heads were "soft" on the exhaust side, so he touched up the exhaust side.
The car was put together last year, to be ready for Thunder. The car broke the rear on the first pass at Thunder with the Exedy clutch. After that, we made four passes in the car in Houston, and destroyed the Exedy clutch. The Exedy was replaced by a Textralia clutch. We made some passes in bad weather with the Textralia clutch and the car ran some 10.90's. Finally a few weeks ago, the car made a few laps at Motosports Ranch with Lou Sr. giving demo rides. In almost a year, thats all the time the car had on it....
So, we decided to make some changes to the car. In talking with Tony M. @ AFR, we had been planning to run a 225 head. Since we were in a time crunch to get the car ready for San Antonio, we decided to just run a 205 head since Lou had run them with pretty good success in his car last year.
Anyhow, Tony provided us witha set of milled 205's and a "Mamo-fied" FAST intake. The plan was to do a A-B swap on the car with no changes other than heads and observe the delta. Let me just say that Tony does a fantastic job on the FAST intake. He fixes some of the current issues with the manifold, and when you look up the port you can certainly see he's been busy up in there. When you compare the differneces to an out of the box FAST 90 the differences are glaring. Tony also has a nice hand, as the cosmetic side of his hand finished stuff really looks nice. While being pretty isn't always important, its certainly nice to see someone take real pride in their work.
The car was taken to MTI where all the work was performed. A baseline dyno was done of the car. As I said above, it had really no time on the motor a few passes and a few dyno pulls, and about 12 miles at the road course. Anyhow, a baseline dyno indicated that something was not right. The car had previously dyno'd 503RWHP at MTI. It was now showing about 460. A fresh set of plugs were installed along with an o2 sensor. Power dropped to 450. A cranking compression test showed about 178-182 psi on all cylinders. A leakdown test was the performed.
#1 - 15%
#2 - 6%
#3 - 7%
#4 - 12%
#5 - 11%
#6 - 8%
#7 - 9%
#8 - 8%
Hmmmmm.... Well, the tune was checked on the car, along with anything else that was readily visible. Nothing really looked off, except the power.
So it was decided since we we were running out of time to swap heads to see if we had an issue with the heads "going away". The heads and intake were swapped, and the combination was re-dynoed. The car made 487.4RWHP and 416.1 RWTQ with the belts on, and 492.9/425.2 with the belts off. The 503 RWHP graph has a small rev limiter bump in it, so the actual peak may not be 503. It may be around 500 or so. Also, MTI was only reving the car to 6800-6900. It'll make power to 7300, so there may be a bit of power up top not shown on the graph.
Anyhow, The fine folks at MTI buttoned up everything, and Jason tightened up the tune just a bit, and we were off to the races. I haven't seen the car in over 9 months, and haven't raced it competitively for almost 2 yrs. It's probably been 10 months since I made a full pass in the car. So, I was anxious to see what it was going to do.
My first impression of the car is that drivability was improved 1000%. The cam in the car is a BIG max effort cam from Ed Curtis. With the LS6 castings you had some low speed surge in first and second. This was not as big on a SD tune as you could load the car into 3rd or 4th and putt around. Once it was under load, it was fine. I noticed that with the 205s on the car all low speed surge is gone. Tip in and drivability was also greatly improved. I drove the car around in the pits creeping around in first with zero drama. I could have easily driven the car in traffic without having to do a lot of dancing on the clutch, etc...
We only had a couple of qualifying passes in the car before eliminations, so I didn't have a lot of time to sort out launch rpm, etc...But I have found that the Aussie clutch is probably the absolute best clutch we've ever had in the car, bar none. It grabs harder than the McLeod dual disc, and it lasted unlike the Exedy that was in the car. There was so much bite with the clutch, that the car was spinning. This may also be due to the fact that we have a set of ET Streets that were a year old.
Anyhow, our next order of business is to play with clutch slip and get the 60's back into the mid 1.4's We were cutting 1.5's all day in the car. I was simply launching the car as we always have, as like I said, I hadn't had time to do any testing to see wha the car might like. I also didn't have any time to test any real changes before eliminations.
DA was +2350 - +2400 on the weather station Even in those rather poor conditions, the car was making good power.
rev limiter @ 6900
60 - 1.5301
330 - 4.5809
1/8 - 7.0952
mph - 97.28
1000 - 9.2673
1/4 - 11.0798
mph - 127.01
60 - 1.5759
330 - 4.5487
1/8 - 7.0281
mph - 96.69
1000 - 9.1672
1/4 - 10.9675
mph - 127.70
Rev limiter @ 7400
60 - 1.5687
330 - 4.5548
1/8 - 7.0271
mph - 98.04
1000 - 9.4505
1/4 - 11.9251
mph - 85.62
(missed 4th on that pass)
60 - 1.5052
330 - 4.5164
1/8 - 7.0003
mph - 98.04
1000 - 9.1539
1/4 - 10.9575
mph - 127.44
60 - 1.5253
330 - 4.4827
1/8 - 6.9476
mph - 98.86
1000 - 9.0896
1/4 - 10.8822
mph - 128.28
60 - 1.5278
330 - 4.4979
1/8 - 6.9628
mph - 98.99
1000 - 9.1016
1/4 - 10.8925
mph - 128.39
So, this brings up several good points. The car is going faster in worse air with less indicated peak HP than it had previously. There are no huge midrange gains shown on the graphs. What I'd like to illustrate by this is that dyno's are a great tuning tool, but the track is what tells the story. Long story short is I can't wait till we get some time to make some runs in Houston in more favorable conditions, as I think we'll put down some impressive numbers in favorable air.
As part of this testing we sent the LS6 heads off the car to Tony to put on his bench so that we could see what the heads make in comparison to the AFR heads we replaced them with. Suprisingly enough, our heads weren't too shabby. In fact I'd say they were probably one of the better set of heads Tony's tested. But, and this is a big but. They were nowhere near the "claimed" numbers we had promised on the heads by Jay. We'd been promised 320-330 cfm heads. In reality they were good, but nowhere near that good. Two ports were tested so we didn't have a realy good or a really bad port skew the numbers. The heads were thoroughly cleaned, etc... to ensure a fair test also.
…........….200….300….400….500….550….600…….
1 3.900....131...194....252...290...302...308......2 35cc
2 3.900....135...196....254...293...306...313......2 35cc
2 4.125....136...198....259...302...316...309......2 35cc (head went turbulent@.600)
AFR 205….145….210….257….290….301….308………205 cc’s
AFR 225….151….221….270….306….315….322………229 cc’s
Our heads were about on par with a 205 head, but the intake runner was 235 ccs vs 205 cc. The exhaust sides (which were re-done) by Greg Good were the best flowing exhaust side Tony had seen in a ported LS6 but were about 89cc. So, Greg managed to fix Jay's issues, he added a bit of volume in doing so, but as I said he did a really nice exhaust side.
……........200….300….400….500….600............Volum e
1 3.900..128....172...204...227...241.............89 cc
2 3.900..126....179...215...232...245.............89 cc
2 4.125..133....176...225...248...256.............89 cc
AFR205….118….171….206….226….240……………..84 cc’s
AFR225….120….180….220….241….250……………..85 cc’s
We had planned to test an A&A vaccum pump on the car, but the kit was missing a hose, so we'll test that sometime in the near future. I'm hoping we'll have even better results to report....
I'm still puzzled as to what killed all the power in the car, but at this point, I can't argue witht he results of the AFR heads. They just flat worked, and the car is running hard.
I'd like to take moment to thank all the guys @ MTI (Jayson, David, and Chris) who went way above and byond the call of duty and stayed until after 8PM at night to ensure the car was as good as it possibly could be. MTI is a great operation, and I can't say enough good things about them.
I'd like to give huge props to Tony Mamo who moved heaven and earth to get us a set of castings, and cranked out a "Mamo special" FAST 90 in record time. Like I said, Tony takes great pride in his work, and it shows...
Anyway, this could be a good place to jump off to discuss how important flow vs velocity is, and how important it is vs just raw flow numbers. Also how better cylinder filling may not show on the dyno, but may show up on the track. Just a few points we might want to discuss....
The current LS6 casting were originally done by Jay @ Absolute Speed. Last year the heads dropped a seat, so the heads were taken over to Greg Good here in Houston. Greg replaced all the seats in the heads. Greg also commented that the heads were "soft" on the exhaust side, so he touched up the exhaust side.
The car was put together last year, to be ready for Thunder. The car broke the rear on the first pass at Thunder with the Exedy clutch. After that, we made four passes in the car in Houston, and destroyed the Exedy clutch. The Exedy was replaced by a Textralia clutch. We made some passes in bad weather with the Textralia clutch and the car ran some 10.90's. Finally a few weeks ago, the car made a few laps at Motosports Ranch with Lou Sr. giving demo rides. In almost a year, thats all the time the car had on it....
So, we decided to make some changes to the car. In talking with Tony M. @ AFR, we had been planning to run a 225 head. Since we were in a time crunch to get the car ready for San Antonio, we decided to just run a 205 head since Lou had run them with pretty good success in his car last year.
Anyhow, Tony provided us witha set of milled 205's and a "Mamo-fied" FAST intake. The plan was to do a A-B swap on the car with no changes other than heads and observe the delta. Let me just say that Tony does a fantastic job on the FAST intake. He fixes some of the current issues with the manifold, and when you look up the port you can certainly see he's been busy up in there. When you compare the differneces to an out of the box FAST 90 the differences are glaring. Tony also has a nice hand, as the cosmetic side of his hand finished stuff really looks nice. While being pretty isn't always important, its certainly nice to see someone take real pride in their work.
The car was taken to MTI where all the work was performed. A baseline dyno was done of the car. As I said above, it had really no time on the motor a few passes and a few dyno pulls, and about 12 miles at the road course. Anyhow, a baseline dyno indicated that something was not right. The car had previously dyno'd 503RWHP at MTI. It was now showing about 460. A fresh set of plugs were installed along with an o2 sensor. Power dropped to 450. A cranking compression test showed about 178-182 psi on all cylinders. A leakdown test was the performed.
#1 - 15%
#2 - 6%
#3 - 7%
#4 - 12%
#5 - 11%
#6 - 8%
#7 - 9%
#8 - 8%
Hmmmmm.... Well, the tune was checked on the car, along with anything else that was readily visible. Nothing really looked off, except the power.
So it was decided since we we were running out of time to swap heads to see if we had an issue with the heads "going away". The heads and intake were swapped, and the combination was re-dynoed. The car made 487.4RWHP and 416.1 RWTQ with the belts on, and 492.9/425.2 with the belts off. The 503 RWHP graph has a small rev limiter bump in it, so the actual peak may not be 503. It may be around 500 or so. Also, MTI was only reving the car to 6800-6900. It'll make power to 7300, so there may be a bit of power up top not shown on the graph.
Anyhow, The fine folks at MTI buttoned up everything, and Jason tightened up the tune just a bit, and we were off to the races. I haven't seen the car in over 9 months, and haven't raced it competitively for almost 2 yrs. It's probably been 10 months since I made a full pass in the car. So, I was anxious to see what it was going to do.
My first impression of the car is that drivability was improved 1000%. The cam in the car is a BIG max effort cam from Ed Curtis. With the LS6 castings you had some low speed surge in first and second. This was not as big on a SD tune as you could load the car into 3rd or 4th and putt around. Once it was under load, it was fine. I noticed that with the 205s on the car all low speed surge is gone. Tip in and drivability was also greatly improved. I drove the car around in the pits creeping around in first with zero drama. I could have easily driven the car in traffic without having to do a lot of dancing on the clutch, etc...
We only had a couple of qualifying passes in the car before eliminations, so I didn't have a lot of time to sort out launch rpm, etc...But I have found that the Aussie clutch is probably the absolute best clutch we've ever had in the car, bar none. It grabs harder than the McLeod dual disc, and it lasted unlike the Exedy that was in the car. There was so much bite with the clutch, that the car was spinning. This may also be due to the fact that we have a set of ET Streets that were a year old.
Anyhow, our next order of business is to play with clutch slip and get the 60's back into the mid 1.4's We were cutting 1.5's all day in the car. I was simply launching the car as we always have, as like I said, I hadn't had time to do any testing to see wha the car might like. I also didn't have any time to test any real changes before eliminations.
DA was +2350 - +2400 on the weather station Even in those rather poor conditions, the car was making good power.
rev limiter @ 6900
60 - 1.5301
330 - 4.5809
1/8 - 7.0952
mph - 97.28
1000 - 9.2673
1/4 - 11.0798
mph - 127.01
60 - 1.5759
330 - 4.5487
1/8 - 7.0281
mph - 96.69
1000 - 9.1672
1/4 - 10.9675
mph - 127.70
Rev limiter @ 7400
60 - 1.5687
330 - 4.5548
1/8 - 7.0271
mph - 98.04
1000 - 9.4505
1/4 - 11.9251
mph - 85.62
(missed 4th on that pass)
60 - 1.5052
330 - 4.5164
1/8 - 7.0003
mph - 98.04
1000 - 9.1539
1/4 - 10.9575
mph - 127.44
60 - 1.5253
330 - 4.4827
1/8 - 6.9476
mph - 98.86
1000 - 9.0896
1/4 - 10.8822
mph - 128.28
60 - 1.5278
330 - 4.4979
1/8 - 6.9628
mph - 98.99
1000 - 9.1016
1/4 - 10.8925
mph - 128.39
So, this brings up several good points. The car is going faster in worse air with less indicated peak HP than it had previously. There are no huge midrange gains shown on the graphs. What I'd like to illustrate by this is that dyno's are a great tuning tool, but the track is what tells the story. Long story short is I can't wait till we get some time to make some runs in Houston in more favorable conditions, as I think we'll put down some impressive numbers in favorable air.
As part of this testing we sent the LS6 heads off the car to Tony to put on his bench so that we could see what the heads make in comparison to the AFR heads we replaced them with. Suprisingly enough, our heads weren't too shabby. In fact I'd say they were probably one of the better set of heads Tony's tested. But, and this is a big but. They were nowhere near the "claimed" numbers we had promised on the heads by Jay. We'd been promised 320-330 cfm heads. In reality they were good, but nowhere near that good. Two ports were tested so we didn't have a realy good or a really bad port skew the numbers. The heads were thoroughly cleaned, etc... to ensure a fair test also.
…........….200….300….400….500….550….600…….
1 3.900....131...194....252...290...302...308......2 35cc
2 3.900....135...196....254...293...306...313......2 35cc
2 4.125....136...198....259...302...316...309......2 35cc (head went turbulent@.600)
AFR 205….145….210….257….290….301….308………205 cc’s
AFR 225….151….221….270….306….315….322………229 cc’s
Our heads were about on par with a 205 head, but the intake runner was 235 ccs vs 205 cc. The exhaust sides (which were re-done) by Greg Good were the best flowing exhaust side Tony had seen in a ported LS6 but were about 89cc. So, Greg managed to fix Jay's issues, he added a bit of volume in doing so, but as I said he did a really nice exhaust side.
……........200….300….400….500….600............Volum e
1 3.900..128....172...204...227...241.............89 cc
2 3.900..126....179...215...232...245.............89 cc
2 4.125..133....176...225...248...256.............89 cc
AFR205….118….171….206….226….240……………..84 cc’s
AFR225….120….180….220….241….250……………..85 cc’s
We had planned to test an A&A vaccum pump on the car, but the kit was missing a hose, so we'll test that sometime in the near future. I'm hoping we'll have even better results to report....
I'm still puzzled as to what killed all the power in the car, but at this point, I can't argue witht he results of the AFR heads. They just flat worked, and the car is running hard.
I'd like to take moment to thank all the guys @ MTI (Jayson, David, and Chris) who went way above and byond the call of duty and stayed until after 8PM at night to ensure the car was as good as it possibly could be. MTI is a great operation, and I can't say enough good things about them.
I'd like to give huge props to Tony Mamo who moved heaven and earth to get us a set of castings, and cranked out a "Mamo special" FAST 90 in record time. Like I said, Tony takes great pride in his work, and it shows...
Anyway, this could be a good place to jump off to discuss how important flow vs velocity is, and how important it is vs just raw flow numbers. Also how better cylinder filling may not show on the dyno, but may show up on the track. Just a few points we might want to discuss....
11-21-2005, 01:01 PM
#3
Great write up J-Rod. Sometimes flow-bench racing doesn't tell the whole story. Glad you were able to prove that high airspeed makes a lot of power in itself. Get some good Houston air and let's see some 10.50s at 130+ out of that Z06. BTW, it was great to finally meet you at SAR!
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
11-21-2005, 03:23 PM
#5
Originally Posted by Phil'sC5vette
Did you mill the AFR heads and cut the pistons ?
(sorry....couldn't resist!)Heads were milled at AFR as J-Rod stated earlier and his pistons already had sizable valve reliefs to handle the big cam with his original combination...
Tony M.
Last edited by Tony Mamo @ AFR; 11-21-2005 at 03:35 PM.
11-21-2005, 03:32 PM
#6
6600 rpm clutch dump of death Administrator
Thread Starter
Chris - No, it doesn't AFAIK
Patrick - Good meeting you too.
Phil - The AFR's were identical in CC's to the LS6 heads we took off to ensure a fair test. The heads we had on the car had been milled to bump compression, the motor has big valve reliefs in it, so we went ahead and milled to match what we had.
Patrick - Good meeting you too.
Phil - The AFR's were identical in CC's to the LS6 heads we took off to ensure a fair test. The heads we had on the car had been milled to bump compression, the motor has big valve reliefs in it, so we went ahead and milled to match what we had.
11-21-2005, 11:40 PM
#7
Teching In
Join Date: Jul 2005
Location: ATX
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Nice post J-Rod. Gotta like the way the engine holds the TQ, instead of letting it expire all too early. I got linked over here from CorvetteForum...for various reasons, I was glad to see this type of post over there man. Do you mind if I save the head flow data you posted?
ps. I've been meaning to get back to your PM, but haven't had time to dig back into all that cam stuff.
ps. I've been meaning to get back to your PM, but haven't had time to dig back into all that cam stuff.
Trending Topics
11-22-2005, 09:37 AM
#9
TECH Resident
Join Date: Sep 2003
Location: Working in the shop 24/7
Posts: 848
Likes: 0
Received 1 Like
on
1 Post
Originally Posted by JS
What was the DA and whats the race weight of this setup..I went 10.80's@124 threw an A4 at 3365lbs in +30 DA's with average S1 LS6 heads and a 224 cam and LSX 
Originally Posted by J-rod
DA was +2350 - +2400 on the weather station Even in those rather poor conditions, the car was making good power.
Good job Jarrod...
Guess you'll need to run at ATCO in mid-November to get respect over here...
Ed
11-22-2005, 09:55 AM
#10
6600 rpm clutch dump of death Administrator
Thread Starter
Originally Posted by JS
What was the DA and whats the race weight of this setup..I went 10.80's@124 threw an A4 at 3365lbs in +30 DA's with average S1 LS6 heads and a 224 cam and LSX
If this combo was in a Camaro with an auto we'd be 60' in the 1.28 range instead of the 1.5 range of an IRS equipped Vette, and we'd be looking at very low 10's possibly very close to the 9's out of it in good weather...
11-22-2005, 10:06 AM
#11
TECH Addict
Join Date: Mar 2004
Location: Fat Chance Hotel
Posts: 2,336
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by J-Rod
Anyway, this could be a good place to jump off to discuss how important flow vs velocity is, and how important it is vs just raw flow numbers. Also how better cylinder filling may not show on the dyno, but may show up on the track. Just a few points we might want to discuss....
11-22-2005, 04:57 PM
#12
6600 rpm clutch dump of death Administrator
Thread Starter
I agree I think too little attention is given to good cylinder filling coupled with good valve events. This might show up more if we had looked at BMEP and BSFC on a before and after.
Honestly though I am puzzled still. I really think this combo should be making more power just as it sits. I honestly think it should really be around 510 or even close to 520. I mean, we can get those numbers with the pump, and with an AL flywheel, but I'd hoped to see them with the car as it is.
Like I said, dyno numbers are nice, and can be a vindication of what you are doing, what is weird is the timeslip etc... seems to indicate perhaps more HP than the dyno numbers are showing. Thats my current quandry. We may need to dyno it at HPE or someplace like that to see if there are any dyno variations, but having dyno'd in both locations before they have always been very close. Like I said, I'm happy with the way the car is doing, I'm just looking to get al the answers I can, because if the car goes 130 or 131 in cold weather with on 493 RWHP, that'd be really interesting...
Honestly though I am puzzled still. I really think this combo should be making more power just as it sits. I honestly think it should really be around 510 or even close to 520. I mean, we can get those numbers with the pump, and with an AL flywheel, but I'd hoped to see them with the car as it is.
Like I said, dyno numbers are nice, and can be a vindication of what you are doing, what is weird is the timeslip etc... seems to indicate perhaps more HP than the dyno numbers are showing. Thats my current quandry. We may need to dyno it at HPE or someplace like that to see if there are any dyno variations, but having dyno'd in both locations before they have always been very close. Like I said, I'm happy with the way the car is doing, I'm just looking to get al the answers I can, because if the car goes 130 or 131 in cold weather with on 493 RWHP, that'd be really interesting...
