Engine Building Options: A Comprehensive list
06-02-2003, 07:00 AM
#1
Three Wheelin'
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Engine Building Options: A Comprehensive list
Lets talk dream motors. 
I am going to list all of the basic motor configurations my research has come up with.
Please everyone comment about your preferences and concerns. I haven't decided which route to go on my own engine yet, and I would appreciate everyone's opinion. If you see anything I messed up on please correct me.
Possibilities:
3.0 Liter block from a S2/968
The only parts you should need for this motor, other than the expensive block, would be custom forged rods, and forged pistons with dishes large enough to lower compression to around 9:1 I assume the heads can flow the required amount of air.
Pros: Lots of Torque. Fairly simple, there is no machining to be done.
Cons: The blocks are crazy expensive. Gas mileage.
3.1 Liters from a bored/stroked 2.5
For this motor you would probably go with Anderson's piston/sleeve combo that Rage2 used in his 2.8 big bore motor. (I use Anderson here because I am not aware of any others available.) Then you would still need the 3 liter crank, and custom forged rods. You would also probably need head work to keep the volumetric efficiency from plummetting.
Pros: Everyone has this block already.
Cons: Seems pretty expensive, considering you would have to get the motor sleeved, and it still might not end up done right. This option seems like the most potentially catastrophic.
2.8 Liter Stroker
All you need here is the 3.0 liter crank and appropriate rods. This is a great bang for the buck. No machining necessary, and fairly straightforward if the motor is out of the car.
Pros: Cheap, easy. Lots of low end torque, which is fun in itself but also allows the turbo to spool faster.
Cons: Same as all the stroker motors, no high RPM fun. If that isn't your objective, then this choice is excellent.
2.8 Liter Big Bore
This would consist of your block, again with the Anderson sleeves. Stock stroke, keeping the boost/high RPM condusive rod angles.
Pros: Not the most expensive, good power potential in the high rpms, though not as much torque as the stroked motors. But, the lower torque means less stress on the drivetrain.
Cons: Sleeving can be dangerous if not done right. Lower torque than a stroker motor, but still more than a 2.5
2.5 liter high revving motor
This seems like the cheapest option, and still allows for alot of power. You will need a good aftermarket rod, and a good durable piston ring set might not be a bad idea for peace of mind. You get to keep the stock rod angles, and not spend as much money as the big bore high revver.
Pros: Cheap. Lots of power in high RPMs
Cons: Not alot of torque. You need high RPMs for power, so not quite as streetable.
If anyone can think of any more combinations/strategies, please add them.
Also, If anything is wrong/left out, please correct me.
I am going to list all of the basic motor configurations my research has come up with.Please everyone comment about your preferences and concerns. I haven't decided which route to go on my own engine yet, and I would appreciate everyone's opinion. If you see anything I messed up on please correct me.
Possibilities:
3.0 Liter block from a S2/968
The only parts you should need for this motor, other than the expensive block, would be custom forged rods, and forged pistons with dishes large enough to lower compression to around 9:1 I assume the heads can flow the required amount of air.
Pros: Lots of Torque. Fairly simple, there is no machining to be done.
Cons: The blocks are crazy expensive. Gas mileage.
3.1 Liters from a bored/stroked 2.5
For this motor you would probably go with Anderson's piston/sleeve combo that Rage2 used in his 2.8 big bore motor. (I use Anderson here because I am not aware of any others available.) Then you would still need the 3 liter crank, and custom forged rods. You would also probably need head work to keep the volumetric efficiency from plummetting.
Pros: Everyone has this block already.
Cons: Seems pretty expensive, considering you would have to get the motor sleeved, and it still might not end up done right. This option seems like the most potentially catastrophic.
2.8 Liter Stroker
All you need here is the 3.0 liter crank and appropriate rods. This is a great bang for the buck. No machining necessary, and fairly straightforward if the motor is out of the car.
Pros: Cheap, easy. Lots of low end torque, which is fun in itself but also allows the turbo to spool faster.
Cons: Same as all the stroker motors, no high RPM fun. If that isn't your objective, then this choice is excellent.
2.8 Liter Big Bore
This would consist of your block, again with the Anderson sleeves. Stock stroke, keeping the boost/high RPM condusive rod angles.
Pros: Not the most expensive, good power potential in the high rpms, though not as much torque as the stroked motors. But, the lower torque means less stress on the drivetrain.
Cons: Sleeving can be dangerous if not done right. Lower torque than a stroker motor, but still more than a 2.5
2.5 liter high revving motor
This seems like the cheapest option, and still allows for alot of power. You will need a good aftermarket rod, and a good durable piston ring set might not be a bad idea for peace of mind. You get to keep the stock rod angles, and not spend as much money as the big bore high revver.
Pros: Cheap. Lots of power in high RPMs
Cons: Not alot of torque. You need high RPMs for power, so not quite as streetable.
If anyone can think of any more combinations/strategies, please add them.
Also, If anything is wrong/left out, please correct me.
06-02-2003, 08:36 AM
#3
Nordschleife Master
Interesting!
But I actually thinks your last option is more expensive than the stroker.
To be able to really raise the revving-potential of this enginge you need a lot of mods! Very expensive parts for the head, work on the crank, exhaust manifold, intake etc.etc.
I guess the simplest route is to get the 3,0 liter crank and new rods.
I'm not sure about what kind of pistons you can use with the stock bore coating for the 3,0 liter block.
But I actually thinks your last option is more expensive than the stroker.
To be able to really raise the revving-potential of this enginge you need a lot of mods! Very expensive parts for the head, work on the crank, exhaust manifold, intake etc.etc.
I guess the simplest route is to get the 3,0 liter crank and new rods.
I'm not sure about what kind of pistons you can use with the stock bore coating for the 3,0 liter block.
06-02-2003, 09:26 AM
#4
Drifting
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Before trying to get the engine to withstand higher revs, I think it would be nice to be actually able to use the existing 6500 rpms or so ... ie, to get the torque curve to stay flat until 6000 rpms instead of that past 5000 rpm fall like on most of the dyno charts I've seen.
Please correct me if I'm completely wrong, but to achieve this one would need modifications to intake, exhaust and probably cam profiles; simply holding enough boost to the redline doesn't seem to solve the problem. Then of course it'll always be a trade-off with lower rpm torque (maybe somewhat fixed by going that 2.8 stroker route?)... but it sure would be nice to have a torque peak at 4000rpm and then hold it until 6000...
Please correct me if I'm completely wrong, but to achieve this one would need modifications to intake, exhaust and probably cam profiles; simply holding enough boost to the redline doesn't seem to solve the problem. Then of course it'll always be a trade-off with lower rpm torque (maybe somewhat fixed by going that 2.8 stroker route?)... but it sure would be nice to have a torque peak at 4000rpm and then hold it until 6000...
06-02-2003, 09:33 AM
#5
Three Wheelin'
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> Originally posted by Duke
But I actually thinks your last option is more expensive than the stroker.
To be able to really raise the revving-potential of this enginge you need a lot of mods! Very expensive parts for the head, work on the crank, exhaust manifold, intake etc.etc.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I wish I knew more about the 951 head. Where are the weak points in an 8V head to support high RPM power? Maybe switching to a 16 Valve head would help?
As far as crank work, I assume you are talking about cross drilling the bearing journals to keep them lubricated at high RPM? Are there other concerns with the crank spinning that fast?
Do you think the length of the intake and exhaust runners have that much of an effect on the location of the torque curve? I think alot of the torque drop off is due to the miniscule exhaust housings most people are using. I think going to a true T04E, or better yet a new GT series Garrett, and not a k26 or t3 hotside would be the first step. I am waiting to see someone produce an affordable crossover pipe to match up with a true T04E. And not the 2 grand one that SFR has to offer.
I mean, a badass, equal length, long runner manifold doesnt help you that much when it bottlenecks into a tiny turbine housing.
You know the more I think about it the more it seems like its the little exhaust housing causing the rapidly falling torque curve. I wonder if there are any dyno charts of people running bigger exhaust housings. How does a kkk #8 compare to a t4?
But I actually thinks your last option is more expensive than the stroker.
To be able to really raise the revving-potential of this enginge you need a lot of mods! Very expensive parts for the head, work on the crank, exhaust manifold, intake etc.etc.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I wish I knew more about the 951 head. Where are the weak points in an 8V head to support high RPM power? Maybe switching to a 16 Valve head would help?
As far as crank work, I assume you are talking about cross drilling the bearing journals to keep them lubricated at high RPM? Are there other concerns with the crank spinning that fast?
Do you think the length of the intake and exhaust runners have that much of an effect on the location of the torque curve? I think alot of the torque drop off is due to the miniscule exhaust housings most people are using. I think going to a true T04E, or better yet a new GT series Garrett, and not a k26 or t3 hotside would be the first step. I am waiting to see someone produce an affordable crossover pipe to match up with a true T04E. And not the 2 grand one that SFR has to offer.
I mean, a badass, equal length, long runner manifold doesnt help you that much when it bottlenecks into a tiny turbine housing.
You know the more I think about it the more it seems like its the little exhaust housing causing the rapidly falling torque curve. I wonder if there are any dyno charts of people running bigger exhaust housings. How does a kkk #8 compare to a t4?
06-02-2003, 10:38 AM
#6
I can't speak for the 951, but I have had some lengthy conversations about 944 na header pipe configurations with some very knowledgeable folks who used to race them in the IMSA Firehawk series. They claimed to have serveral different sets of exhaust headers that they would swap out depending on which track they were running and weather conditions. I have to believe some of that would hold true for the 951 as well, altho what configuration would be best is beyond me.
Regards,
Regards,
06-02-2003, 05:23 PM
#7
Nordschleife Master
Above 7000rpm the lifters can't keep up.
I think the biggest factor is the weight. The head has only 8 valves which means they're large and heavy, the pistons are very heavy, the rods are heavy etc.
To get a usable powerband high up I suppose this would be nice/needed:
A 16 valve head with lightweight parts like titanium retainers, solid lifters, harder valve springs, new stronger and lighter (which I think almost every aftermarket item is) rods and pistons, lightweight flywheel etc.
So I suppose the biggest bang for the buck upgrade in this department would be a 2,8 stroker with a large turbo.
I suppose a dream configuration would be a 3,0 liter 968-block de-stroked with a worked 951-crankshaft and all the goodies I mentioned above like 16 valve head etc.
Can I have one of those, please?
I think the biggest factor is the weight. The head has only 8 valves which means they're large and heavy, the pistons are very heavy, the rods are heavy etc.
To get a usable powerband high up I suppose this would be nice/needed:
A 16 valve head with lightweight parts like titanium retainers, solid lifters, harder valve springs, new stronger and lighter (which I think almost every aftermarket item is) rods and pistons, lightweight flywheel etc.
So I suppose the biggest bang for the buck upgrade in this department would be a 2,8 stroker with a large turbo.
I suppose a dream configuration would be a 3,0 liter 968-block de-stroked with a worked 951-crankshaft and all the goodies I mentioned above like 16 valve head etc.
Can I have one of those, please?
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06-02-2003, 06:17 PM
#9
Three Wheelin'
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I did a search and found Tony Describing his engine:
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> Origingally posted by TonyG
Speed Force Racing 4 into 1, Burns 321 STainless header/cross over, with a 304SS 3" exhaust using (3) Borla XR-1 Race mufflers (cost over $3500)
John Milledge Head/Billet Cam/Valvetrain (spend over $4000)
Full Garrett turbo, 60-1Hifi/.69 a/r stage 5 trim
Intake cut in 3 pieces and extensively ported to match the John Milledge Head/valve train ($1500 spent).
Larger throttle body.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">All of these contribute to a flat torque curve, upwards of 7500 RPM.
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> Origingally posted by TonyG
Speed Force Racing 4 into 1, Burns 321 STainless header/cross over, with a 304SS 3" exhaust using (3) Borla XR-1 Race mufflers (cost over $3500)
John Milledge Head/Billet Cam/Valvetrain (spend over $4000)
Full Garrett turbo, 60-1Hifi/.69 a/r stage 5 trim
Intake cut in 3 pieces and extensively ported to match the John Milledge Head/valve train ($1500 spent).
Larger throttle body.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">All of these contribute to a flat torque curve, upwards of 7500 RPM.
06-03-2003, 12:12 AM
#10
Three Wheelin'
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The stroker is starting to sound better and better to me. It is fairly cheap and something I can do myself. I am starting to think the hell with high RPMS, torque is fun!
Lemme see if I understand what I need here:
3.0 liter crank, custom rods. I have also heard that you need an aftermarket piston with a lower wrist pin. I hope not, because if I eventually plan to bore the engine after doing the stroker, I will have to buy yet another set of custom pistons. Has anyone done a 2.8 liter stroker using the stock pistons?
Lemme see if I understand what I need here:
3.0 liter crank, custom rods. I have also heard that you need an aftermarket piston with a lower wrist pin. I hope not, because if I eventually plan to bore the engine after doing the stroker, I will have to buy yet another set of custom pistons. Has anyone done a 2.8 liter stroker using the stock pistons?
06-03-2003, 12:16 AM
#11
Drifting
I would choose either the 2.8 stroker or the 3 liter. From everyhting I've read, properly sleeving an engine is an art and to get it properly done you need to spend big bucks with someone like Milledge, Gomes, or Norwood.
As far as the higher reving motors it is important to note that the stresses on the internal parts increases as the square of the engine speed. A nicely setup turbo can give you high end torque, with a lot less stress on both the valvetrain and bottom end. I think that you have the right of it Boostguy951 that its turbo exhaust side selection that is causing the high end drop off. Check out the dyno for the Vitesse Stage 3 kit - pretty steady on the high end.
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=18;t=004650" target="_blank">http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=18;t=004650</a>
Although you can use a turbo to "tune" the high end, you cannot use it to add low end torque. Enter the 3 l and 2.8 l stroker. Both would give a nice boost to the low end and in conjunction with a nice turbo with a good engine management system, generate lots of hp and torque, and most important they should be more robust and reliable to the high rpm and/or bore-sleeved engined
As far as the higher reving motors it is important to note that the stresses on the internal parts increases as the square of the engine speed. A nicely setup turbo can give you high end torque, with a lot less stress on both the valvetrain and bottom end. I think that you have the right of it Boostguy951 that its turbo exhaust side selection that is causing the high end drop off. Check out the dyno for the Vitesse Stage 3 kit - pretty steady on the high end.
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=18;t=004650" target="_blank">http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=18;t=004650</a>
Although you can use a turbo to "tune" the high end, you cannot use it to add low end torque. Enter the 3 l and 2.8 l stroker. Both would give a nice boost to the low end and in conjunction with a nice turbo with a good engine management system, generate lots of hp and torque, and most important they should be more robust and reliable to the high rpm and/or bore-sleeved engined
06-05-2003, 10:57 PM
#13
Rennlist Member
Even though I paid the price, I have the dream motor I wanted. I only wonder now what MOTEC engine management would do for me? Still dreamin' and never satisfied. Then again I do love and appreciate what I have...
06-06-2003, 12:28 AM
#14
Racer
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See signature... its made out of a 2.5L block. Pistons are cut for 8:1 compression with 16V head. Custom this that and the other thing. BTW, Huntley is building it for me. They also offer a 3.1L, 3.0L, 3.2L, 3.4L, 2.8L, etc.
DFASTEST951 - 21psi on race gas, I'm assuming? And by street legal, you mean it has seatbelts? Now, here's my real question for you. Does it pass smog in NV (when my motor's done, the state might have to think I live in NV, not CA)?
DFASTEST951 - 21psi on race gas, I'm assuming? And by street legal, you mean it has seatbelts? Now, here's my real question for you. Does it pass smog in NV (when my motor's done, the state might have to think I live in NV, not CA)?
06-06-2003, 12:42 AM
#15
Addict
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A 3 liter block is good bang for the buck? Neither headers/cross over, nor the intake manifold bolt up to the 3 liter block, isn't that a good bit of custom fabbing? (aside from the not too common pistons/rods you'll need to go along w/the 3 liter turbo project).
Ahmet
Ahmet