XKR Super G... Going for Mach 1
09-09-2009, 05:55 PM
#1021
I agree, to me if the heads are off for the money why not throw a little work at them it can't hurt? It might not be a requirement but why not while your at it. I also understand opening up things only goes so far if you have a bottle neck else where.
09-09-2009, 06:05 PM
#1022
The MadScientist and Luie raced at ZdayZ 2008 when Luie still had his car. Both MadScientist and Luie had about the same setup.....Luie 850bb......MS 20G.....
MS has Cosworth heads.....Luie Stock heads.
This was a high speed roll....From what I was told.....MS pulled on Luie....WHY???
From what I was told...The only difference between both cars was the Cosworth Heads.
MS has Cosworth heads.....Luie Stock heads.
This was a high speed roll....From what I was told.....MS pulled on Luie....WHY???
From what I was told...The only difference between both cars was the Cosworth Heads.
I started debating with myself because honestly, for big hp builds, I expected to see a bigger difference. I should know better. I usually do more research and/or analysis before posting. The initial posts by the guy in the other thread got me going.
Last edited by ttg35fort; 09-09-2009 at 06:09 PM.
09-09-2009, 06:16 PM
#1023
The biggest difference between Tom;s SP build and every other log manifold build is the turbine housings used. Tom has a true T3 or T4 while everyone else uses a T25 for fitment reasons.
One very respected tuner keeps telling me that the reason you dont see mid 20+ psi tunes on log manifold/T25 housing setups, is that the backpressure gets soo much that you are entering headlift without detonation territory. You CAN NOT just keep raising the boost to reach your power goals. If you could, why all the weak dynos with gt30 series turbos? A pair of those could easily run in the 800s on pump gas and well into the 900's on race. Yet no one has come close to that. There are tons of dyno sheets of single gt3071 and gt3076s making 400+ easily on other platforms that can use the larger housings
Trying to push 1000 whp thru a T25 housings is going to be inefficient to say the least.
Thats why the highest most strung out dyno using a log manifold/T25 is barely over 800 whp (and even GTMs extreme APS kit was on a 4.24L car)
Hal made more power with less boost because he is running a much larger t4 turbine housing. I'd bet an extremely different amount of backpressure.
Sure nice heads are good, but fitting T3 or T4 housing (ie frame notching) is a much better place to spend money on and way more gains can probably be had there
One very respected tuner keeps telling me that the reason you dont see mid 20+ psi tunes on log manifold/T25 housing setups, is that the backpressure gets soo much that you are entering headlift without detonation territory. You CAN NOT just keep raising the boost to reach your power goals. If you could, why all the weak dynos with gt30 series turbos? A pair of those could easily run in the 800s on pump gas and well into the 900's on race. Yet no one has come close to that. There are tons of dyno sheets of single gt3071 and gt3076s making 400+ easily on other platforms that can use the larger housings
Trying to push 1000 whp thru a T25 housings is going to be inefficient to say the least.
Thats why the highest most strung out dyno using a log manifold/T25 is barely over 800 whp (and even GTMs extreme APS kit was on a 4.24L car)
Hal made more power with less boost because he is running a much larger t4 turbine housing. I'd bet an extremely different amount of backpressure.
Sure nice heads are good, but fitting T3 or T4 housing (ie frame notching) is a much better place to spend money on and way more gains can probably be had there
I don't even know what housings my new turbos have. It probably would have been good to check, but now I already have my exhaust manifolds ceramic coated. I did that with my Greddy kit before I decided to sell it. That was a waste. I took it in the shorts over that blunder. The buyer got a h@ll of a deal, though.
09-09-2009, 06:26 PM
#1025
Everything with log manifolds with Garret turbos uses a T25 housing. Only the single and tubular manifold kits offer bigger manifolds (and a TON more install work)
ATP turbo sells t25 housing that they say flows as much as a true T3 but they are expensive. Not something you'd do on a brand new GTM kit. But if GTM offered that as an upgrade, it would be very interesting to see dyno comparisons.
Not tryin to start a bandwagon, but big numbers with the current kits might take a lil more than we all expect. I just want XKR, TTfort, Sylvan Lake, smalltuner, and Blackbird to hurry the hell up with their builds and get some high boost #'s so I can choose my kit
ATP turbo sells t25 housing that they say flows as much as a true T3 but they are expensive. Not something you'd do on a brand new GTM kit. But if GTM offered that as an upgrade, it would be very interesting to see dyno comparisons.
Not tryin to start a bandwagon, but big numbers with the current kits might take a lil more than we all expect. I just want XKR, TTfort, Sylvan Lake, smalltuner, and Blackbird to hurry the hell up with their builds and get some high boost #'s so I can choose my kit
Very good point.
I don't even know what housings my new turbos have. It probably would have been good to check, but now I already have my exhaust manifolds ceramic coated. I did that with my Greddy kit before I decided to sell it. That was a waste. I took it in the shorts over that blunder. The buyer got a h@ll of a deal, though.
I don't even know what housings my new turbos have. It probably would have been good to check, but now I already have my exhaust manifolds ceramic coated. I did that with my Greddy kit before I decided to sell it. That was a waste. I took it in the shorts over that blunder. The buyer got a h@ll of a deal, though.
Last edited by str8dum1; 09-09-2009 at 06:29 PM.
09-09-2009, 06:36 PM
#1026
Registered User
yup, this pull only goes to 6k rpm (hit boost cut that was set at 30psi).....but stock cams we all know what happens above 6250rpm..ugh...so maybe would have made a couple more hp going to the peak hp at 6250rpm.....but didn't need to push anymore to get 5hp lol
I rev to 7k now at the track (and the odd race where I really need it on pump)
*edit* - added my car "bone stock" vs "14psi" vs "30psi" layed over on one graph lol
Tom
I rev to 7k now at the track (and the odd race where I really need it on pump)
*edit* - added my car "bone stock" vs "14psi" vs "30psi" layed over on one graph lol
Tom
Last edited by thom000001; 09-09-2009 at 06:43 PM.
09-09-2009, 07:11 PM
#1028
Registered User
09-09-2009, 07:17 PM
#1030
I just compared the cross-sectional areas of the T25, T3 and T4 turbine inlets. Here are the results:
T25: 1735 mm^2
T3: 2412 mm^2
T4: 3623 mm^2
The T3 turbine inlet is 39% larger than the T25 inlet.
The T4 turbine inlet is 109% bigger than the T25 inlet.
Those ratios are pretty significant, and support str8dum1's statement regarding the turbine inlet size.
T25: 1735 mm^2
T3: 2412 mm^2
T4: 3623 mm^2
The T3 turbine inlet is 39% larger than the T25 inlet.
The T4 turbine inlet is 109% bigger than the T25 inlet.
Those ratios are pretty significant, and support str8dum1's statement regarding the turbine inlet size.
09-09-2009, 07:19 PM
#1031
Registered User
Trust me, Larry bugs me all the time to do cams lol
If we would have known it would make power like this, I would have done cams up front.
Tom
If we would have known it would make power like this, I would have done cams up front.
Tom
09-09-2009, 07:22 PM
#1032
Registered User
So just based on cross section....a single T4 flange can outflow 2 T25 flanges no matter what. No wonder Supra's will opt for a bigger single T4 over two teeny T25's (and its half the cost to boot for them)
tom
tom
I just compared the cross-sectional areas of the T25, T3 and T4 turbine inlets. Here are the results:
T25: 1735 mm^2
T3: 2412 mm^2
T4: 3623 mm^2
The T3 turbine inlet is 39% larger than the T25 inlet.
The T4 turbine inlet is 109% bigger than the T25 inlet.
Those ratios are pretty significant, and support str8dum1's statement regarding the turbine inlet size.
T25: 1735 mm^2
T3: 2412 mm^2
T4: 3623 mm^2
The T3 turbine inlet is 39% larger than the T25 inlet.
The T4 turbine inlet is 109% bigger than the T25 inlet.
Those ratios are pretty significant, and support str8dum1's statement regarding the turbine inlet size.
09-09-2009, 07:46 PM
#1035
I was much at fault for the delay. I switched gears on him and asked him to look into adding support around the tops of the cylinders (I got the idea from another thread posted here about a month ago).
I'm hoping for around 675 whp on 93 octane and 750 whp with the meth system on. I should be able to get there. My 3.5L motor got to over 600 whp on 93 octane, and with the 4.0L motor I am increasing displacent by about 14.2%. Add 14.2% to 600 and you arrive at 685. I'm also putting in bigger cams and bigger turbos.
Also, the last time around my spark plugs were 1 step colder. We pulled the timing way, way back. This time we are going to use 2 step colder plugs with the hopes of being able to run a little more timing. Perhaps this will let us get closer to 700 whp on 93 octane. I'm not holding my breath, but it would be nice.
09-09-2009, 08:11 PM
#1036
This is ot, but this is as good as anyplace to bring it up since my hardcore friends are in here:
It seams to me that there would be a significant benefit in long term longevity of our high hp motors to use cranks with larger journal diameters. Heck, some of us are already doing a lot of mods to our shorblocks, e.g., aftermarket rods, crankshafts and main caps. It doesn't seem like it would be that big of a deal to enlarge the main caps and the bearing seats in the block, nor increase the diameter of the rod's housing bore. Other than perhaps weight, why wouldn't/hasn't this been looked into???
Any thoughts???
It seams to me that there would be a significant benefit in long term longevity of our high hp motors to use cranks with larger journal diameters. Heck, some of us are already doing a lot of mods to our shorblocks, e.g., aftermarket rods, crankshafts and main caps. It doesn't seem like it would be that big of a deal to enlarge the main caps and the bearing seats in the block, nor increase the diameter of the rod's housing bore. Other than perhaps weight, why wouldn't/hasn't this been looked into???
Any thoughts???
Last edited by ttg35fort; 09-09-2009 at 09:13 PM.
09-10-2009, 06:28 AM
#1039
I just compared the cross-sectional areas of the T25, T3 and T4 turbine inlets. Here are the results:
T25: 1735 mm^2
T3: 2412 mm^2
T4: 3623 mm^2
The T3 turbine inlet is 39% larger than the T25 inlet.
The T4 turbine inlet is 109% bigger than the T25 inlet.
Those ratios are pretty significant, and support str8dum1's statement regarding the turbine inlet size.
T25: 1735 mm^2
T3: 2412 mm^2
T4: 3623 mm^2
The T3 turbine inlet is 39% larger than the T25 inlet.
The T4 turbine inlet is 109% bigger than the T25 inlet.
Those ratios are pretty significant, and support str8dum1's statement regarding the turbine inlet size.
Don't worry, I won't start postulating about how lowering EGTs might help...
We did banter a bit about the twin scroll GT35R turbos mated to a quick spool valve on the g35driver thread back in June for Mike's build.
Last edited by rcdash; 09-10-2009 at 06:32 AM.
09-10-2009, 07:00 AM
#1040
Registered User
we thought about the quick spool valves on mine as well....just don't know if there is quite enough room or an actual need on my setup.....maybe after doing the cams though, we'll see
tom
tom