Ok, so I was on the Forged website, and I was glancing over the S1 and S2 built motors. Obviously, the S2 is sleeved, but, when reading about it, I saw a note that said those who road race are better off using the S1 unsleeved block. Why is that exactly? Additionally, what advantages or disadvantages are there between a 3.8L sleeved setup and something like the 3.8L stroker that GTM offers? Presumably, the sleeved motor gains displacement in stroker, whereas the 3.8L stroker picks up its extra displacement in the stroke, but what are the differences in terms or redlines and power/torque curves?

 

anyone?

 

short stroke motors rev faster due to less time to tdc and will perform better as a quick rev high rpm motor.stroker's generally have more recipricating weight and lose rev potential with the longer path to tdc,they are ideal as a mid-range tourqey motor

 

Yeah, thats fairly basic stuff that I already know, but considering the characteristics of the VQ, which would be more beneficial?

 

what do you want to do?

 

I think they recommend the unsleeved motor in roadrace applications, because the aftermarket sleeves might run hotter. But I have also heard some people that say with the proper coolant system you will not be able to tell a difference. If you want a 3.8 liter, then most cost effetive way is to sleeve the motor and run 100mm pistons. I dont see any downfall to do this, besides maybe the wall of the sleeves will be thinner then the 3.8 stroker kit, but I am sure they will be thick enough to take anything you will be throwing at it. As most people on this forum think 500wheel is a lot power.

 

i thought the sleeved runs hotter myth was busted?

 

Read my edited post.

 

Thats basically what I thought. But pardon the n00b question, why would the sleeves running hotter make a difference? Would it potentially lead to knock or something like that? So, it would seem then that for someone wanting to run with higher revs (me), the sleeved motor with 100mm pistons would be the way to go?

Additionally, the whole point of sleeving is to reinforce the cylinder wall. With that being said, how would a sleeved 3.8L motors cylinder wall be any weaker than an unsleeved 3.8L stroker's cylinder wall?

 

oh o.k.

 

I am no expert on the subject, but heat is a factor in an engines death. The hotter the engine gets the more stress will be placed on the components inside of it. I am sure either setup would be great for high revs, as the GTM kit has a very nicely designed crank and components, but the stock crank is still a good piece. I would look more at cost, then which is better vs the other. I would love the GTM stroker kit, as it really has no downfalls. But on my bugget the 100mm pistons would be the way that I would go.

 

thawk has it right,for roadrace and rowing gears i would sleeve for a rev happy motor,i'm a 1/4 mile guy so i always hunt for torque.either way cubes rule.if you want to rev you will need to chop weight from the vavle train.

 

I was talking about the sleeved 3.8 with stock crank having thinner cylider walls, because the sleeves come in the stock 3.5 size. In order to put the 100mm pistons in a good amount of boring has to be done. This might have an effect on potential power, but I am sure it could still take more power then an unsleeved block.

Did that answer your question?

 

Additionally, knowing the VQ's power curve with FI, notably, how it falls off in the high revs, I wonder if either setup would give substantial gains to power above 6500ish RPM.

 

a sleeved block will have better strength with less bore distortion

 

Probably not. That is more in head/cams, manifold design, and turbo efficeincy.

 

hmmm, thanks guys, theres some good information here


With a larger (albeit, only slightly) displacement, certainly the turbos would spool up at least a little quicker, and it would seem to me that the bored out, sleeved motor would spool them up faster than the stroked motor would. For the kind of driving I do; no racing, or at least not with any frequency, I think the sleeved motor would best suit me.

 

to get a motor to rev the formula is fairly simple,short stroke,weight reduction,high lift/duration cams and the most important is friction.if i was going in your direction i would definitaly look into coated bearings,pistons and valves.

 

everyone wants to talk about when their turbos come on but people forget to consider if my motor revs freely and yours doesnt my boost can come on much later and still kick your ***.if we are 1000 rpm apart and i rev 1500 rpms quicker whose boost is better?

 

Maybe for extreme rev most of that is preferable, but to take it to 7500-8k just be sure whoever built your motor knew what they were doing and include a good size cam with good springs.