Forged Performance: Engine inspection after 25K miles of abuse
08-14-2007, 03:28 PM
#81
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Originally Posted by majik16106
just curious... where have you seen that? because ive always been under the opposite impression as well, it may get a little hotter but the difference shouldnt matter much when compared to the benifit of the added cooling to the turbo. i know a lot of japanese tuners who use mitsu-styled or non watercooled turbos often run them at far less boost pressure during track days than what the car is tuned for, but the tuners using water cooled BB style turbos almost always run them at or very close to what they tune them at.
08-14-2007, 03:31 PM
#83
Congratulations on your next build to come. I knew when you told me about a few weeks ago, I could tell you really wanted to go this route and would be happier with a motor for tracking purposes. It's obviously where your passion lies.
Road course driving is what it's all about. It test all the abilities of your car and yourself. Just an all around way of experiencing driving skill. IMO. Good luck with it all.
Road course driving is what it's all about. It test all the abilities of your car and yourself. Just an all around way of experiencing driving skill. IMO. Good luck with it all.
08-14-2007, 05:18 PM
#84
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FYI, here is part of the response I got from Steve Demirjian, one of the patent holders on the Darton MID sleeves:
And for what it's worth, he also claims to know of VQ35 drag engines using MID sleeves that produce more than 2000hp at over 60 pounds of boost!
I don't know what kind of reasoning those folks ... are using but it is not scientific. Since aluminum transfers heat considerably faster than iron, more heat will be transferred from the cylinder to the coolant with aluminum lined cylinder walls vs. iron cylinder walls. Thus, the engine will make less power and the coolant will run hotter with aluminum lined cylinder walls than it will with iron cylinder walls since heat energy is wasted to the cooling system instead of doing work on the piston.
...
Bottom line, an engine with aluminum lined walls will transfer more heat to the coolant than one with iron walls whether an iron block or MID block. Thus the coolant will run hotter not cooler with an aluminum wall dry sleeved block.
Steve
...
Bottom line, an engine with aluminum lined walls will transfer more heat to the coolant than one with iron walls whether an iron block or MID block. Thus the coolant will run hotter not cooler with an aluminum wall dry sleeved block.
Steve
08-14-2007, 05:39 PM
#85
^ more heat to melt pistons, increase the risk of detonation and decrease reliability? Yes they will run hotter and likely increase power (although as stated in this thread that's no longer the goal, nor is drag racing the application).
Basically it seems you (and your consultant) are agreeing with what's been said except for the coolant temps reported by Philthy and Sharif being noted as higher with MID sleeves. Hard to argue with real world experience...
Basically it seems you (and your consultant) are agreeing with what's been said except for the coolant temps reported by Philthy and Sharif being noted as higher with MID sleeves. Hard to argue with real world experience...
08-14-2007, 05:43 PM
#86
Originally Posted by MacGuffin
FYI, here is part of the response I got from Steve Demirjian, one of the patent holders on the Darton MID sleeves:
And for what it's worth, he also claims to know of VQ35 drag engines using MID sleeves that produce more than 2000hp at over 60 pounds of boost!
And for what it's worth, he also claims to know of VQ35 drag engines using MID sleeves that produce more than 2000hp at over 60 pounds of boost!
But, if we use his logic, than we shouldnt run a cooling system, so we can keep all the heat in the engine for max power.
Endurance racing engines, and drag racing engines couldnt be more different.
08-14-2007, 05:44 PM
#87
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I don't know what kind of reasoning those folks ... are using but it is not scientific. Since aluminum transfers heat considerably faster than iron, more heat will be transferred from the cylinder to the coolant with aluminum lined cylinder walls vs. iron cylinder walls. Thus, the engine will make less power and the coolant will run hotter with aluminum lined cylinder walls than it will with iron cylinder walls since heat energy is wasted to the cooling system instead of doing work on the piston.
...
Bottom line, an engine with aluminum lined walls will transfer more heat to the coolant than one with iron walls whether an iron block or MID block. Thus the coolant will run hotter not cooler with an aluminum wall dry sleeved block.
Steve
...
Bottom line, an engine with aluminum lined walls will transfer more heat to the coolant than one with iron walls whether an iron block or MID block. Thus the coolant will run hotter not cooler with an aluminum wall dry sleeved block.
Steve
My understanding is that the benefit of aluminum-walled cylinders leads to the ability to increase compression and/or advance timing secondary to the heat transfer of aluminum v. iron, so making less power doesn't seem to make sense either?
08-14-2007, 06:06 PM
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Originally Posted by Sharif@Forged
For drag racing....and massive power...yes. For road racing..no. I am not going to argue with the manufacturer of the sleeves.
But, if we use his logic, than we shouldnt run a cooling system, so we can keep all the heat in the engine for max power.
Endurance racing engines, and drag racing engines couldnt be more different.
But, if we use his logic, than we shouldnt run a cooling system, so we can keep all the heat in the engine for max power.
Endurance racing engines, and drag racing engines couldnt be more different.
I actually think Steve's logic and your inference from it are correct: If the engine could hold together, you would get the most power out by not running a cooling system. Looked at another way, if you had perfect thermodynamic efficiency, then all of the energy of the burning fuel would go into the crankshaft and none into waste heat, so no cooling system would be necessary. Perfect thermodynamic efficiency is impossible, so there is some waste heat that must be removed by the cooling system; but if you remove more heat than the minimal waste heat, then you are robbing the engine of useful work. Think of the extreme case: cylinder walls with infinite thermal conductivity and no resistance to heat transfer. All of the heat energy from the burning fuel in such a cylinder would immediately go out into the cooling jacket, raising the coolant temperature while doing no useful work.
All that being said, while I don't find the arguments for why stock dry sleeves will run cooler at all persuasive, I am still very interested in seeing actual track data, because that is what matters in the end.
Now, for what it is worth, Steve is not a manufacturer of Darton's MID sleeves. He worked with Darton to develop and patent the product, but he runs his own shop, Race Engine Development. It should come as no surprise that his shop has an outstanding reputation for quality MID sleeve installations.
08-14-2007, 06:13 PM
#90
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Originally Posted by abyss
MacGuffin must work for them. Kinda odd all his post history is in this thread fighting for the precious sleeves.
Don't be absurd. I don't work for Darton or RED, nor do I have any vested interest in MID sleeves. They are by no means precious to me. I'm simply interested in VQ35-based endurance racing engines, and I am trying to figure out why some of you think the stock dry sleeves are better for such engines. I'm sorry if my irreverence for "just so" stories and received wisdom offends you, but that's just the way I am when it comes to technical and engineering matters.
08-14-2007, 06:20 PM
#91
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plenty of OTHER aluminum block turbo endurance engines with no sleeves seem to work just fine
is this thread even about how well these motors hold up anymore or have we moved on to bench physics?
is this thread even about how well these motors hold up anymore or have we moved on to bench physics?
08-14-2007, 06:23 PM
#92
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I'm curious. How about attaching a medium sized fan to the engine oil cooler and have it connected to the radiator fans for current? Wouldn't this help keep the engine oil cooler and instead of passive but also active cooling!!
08-14-2007, 06:26 PM
#93
The point here is that for endurance racing on most tracks, sleeves serve no useful purpose. The stock block seems to do just fine with the desired horsepower goals.
MacGuffin, I don't think anyone is really disagreeing with you. Most of what Steve said is straightforward. His notion about what the coolant temps will or will not do are dependent on a number of variables, including the cooling system employed, ambient temps, etc.
And you think Steve's opinion might just be a little biased considering he helped to design the thing in question? By report, it appears that MID sleeves run hotter. I don't know that you're going to get much more concrete data on a public forum...
MacGuffin, I don't think anyone is really disagreeing with you. Most of what Steve said is straightforward. His notion about what the coolant temps will or will not do are dependent on a number of variables, including the cooling system employed, ambient temps, etc.
And you think Steve's opinion might just be a little biased considering he helped to design the thing in question? By report, it appears that MID sleeves run hotter. I don't know that you're going to get much more concrete data on a public forum...
08-14-2007, 06:30 PM
#94
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Originally Posted by MacGuffin
Don't be absurd. I don't work for Darton or RED, nor do I have any vested interest in MID sleeves. They are by no means precious to me. I'm simply interested in VQ35-based endurance racing engines, and I am trying to figure out why some of you think the stock dry sleeves are better for such engines. I'm sorry if my irreverence for "just so" stories and received wisdom offends you, but that's just the way I am when it comes to technical and engineering matters.With the setup Sharif is going for, there's absolutely no reason to go with sleeves. He already stated his power goals, and the fact that he wanted it to be a lower cost build. He could push that turbo setup to his limits without a sleeved block.
If there is any cooling advantage then that's just an added bonus to a more cost efficient build.
08-14-2007, 06:38 PM
#95
Not really track data MacGuffin, but you might find this link interesting as it has some actual reported temps: https://my350z.com/forum/engine-and-drivetrain/195998-rear-cylinder-coolant-bypass-modification.html
08-14-2007, 06:46 PM
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rcdash, I don't see how you can conclude that no one is really disagreeing with me (by which I presume you mean with Steve, since I'm more just asking questions than trying to provide answers.) When some are saying that the stock dry sleeves will result in lower coolant temps because of increased thermal conductivity, and Steve is saying that increased thermal conductivity will lead to higher coolant temps and that, if anything, MID sleeves will result in lower coolant temps, the claims hardly seem to be in agreement.
Your claim that sleeves serve no useful purpose for endurance racing also seems overstated and undersupported. Even if there is no difference in coolant temps, MID sleeves do allow for much larger engine displacement and/or for very different bore to stroke ratios. Either or both of those can be very beneficial to endurance racing engines.
Regardless, my point was never to claim that MID sleeves serve some useful purpose for endurance racing engines. I got into this discussion after Sharif claimed that the stock cylinder liners were better for endurance racing engines -- i.e., that MID sleeves do not just serve no useful purpose for endurance racing engines, but that they are detrimental relative to the stock liners. I remain unconvinced that such is the case, and I am not at all persuaded by the reasons given for the claim. I do, however, still look forward to seeing Sharif's account of his on track experience.
Your claim that sleeves serve no useful purpose for endurance racing also seems overstated and undersupported. Even if there is no difference in coolant temps, MID sleeves do allow for much larger engine displacement and/or for very different bore to stroke ratios. Either or both of those can be very beneficial to endurance racing engines.
Regardless, my point was never to claim that MID sleeves serve some useful purpose for endurance racing engines. I got into this discussion after Sharif claimed that the stock cylinder liners were better for endurance racing engines -- i.e., that MID sleeves do not just serve no useful purpose for endurance racing engines, but that they are detrimental relative to the stock liners. I remain unconvinced that such is the case, and I am not at all persuaded by the reasons given for the claim. I do, however, still look forward to seeing Sharif's account of his on track experience.
08-14-2007, 06:48 PM
#98
MacGuffin> I give; no contradiction was intended 
. Hope you find what you're looking for
ha ha - them bearings look awesome 
EDIT: now that you blew it up 4x, I see a little speckling on the exterior. Corrosion on the pauter rods? In 1000 yrs, I bet they'll blow up in some poor sap's motor who buys em off you
. Hope you find what you're looking for
Originally Posted by Sharif@Forged
So how about the bearings...that's what this thread was really about.
EDIT: now that you blew it up 4x, I see a little speckling on the exterior. Corrosion on the pauter rods? In 1000 yrs, I bet they'll blow up in some poor sap's motor who buys em off you
Last edited by rcdash; 08-14-2007 at 06:53 PM.
08-14-2007, 06:49 PM
#99
Originally Posted by MacGuffin
When some are saying that the stock dry sleeves will result in lower coolant temps because of increased thermal conductivity,