I'm building a big bore motor for a VQ swapped Sentra, and was wondering what size bore is considered safe for the Darton sleeves? I've used AEBS sleeves in the past, and ran 101mm, but, Darton claims that 100mm is the max? I don't plan on making over 400whp, so, maybe the extra 1mm would be ok? I assume that Darton claims 100mm, because they see customers trying to make big power if they're sleeving a block..?

Just curious.. I'd like to squeeze out every cube that I can, if we're going to do this.

BTW, the car has already run 12.20's @ 110-111mph, all motor.

It's a 2004 Spec V, with a full cage, full interior (down to the spare tire/jack), and ABS. It weighs around 3100lbs with a tank of gas, and the owner driving.

I built a DE motor, with ported heads, JWT C8's and their spring package, 11.5:1 HR pistons, H-beams, studs, JWT clutch/flywheel, and a tune that I worked on with Technosquare back and forth, datalogging, and making changes. I have never dyno'd the car, but, with a 110.85mph trap speed, at 3100lbs, we should be just over 300whp. The motor spins to 7800rpm..

Here's a few pics/video..




Low 12 second pass..
http://www.youtube.com/watch?v=dsIz4eEe_lU

Anyway.. thought you guys might enjoy.. I know that it's not a Z, but, I love working with the VQ series of engines. I've kept myself busy for almost 5 years, swapping them into the Spec V chassis.

Let me know what you guys have run, as far as bore size, on low HP, big bore Darton sleeved engines.. I want to hit 340-350whp with a big bore setup, and larger valves to take advantage of the deshrouding that the bigger bores will create.

Travis

 

there are maybe 3 or 4 people with stroked NA's and of those I only know 2 that are currently running in cars. I don't think there is really a wealth of info out there for such a setup as this community tends to embrace boost. I've yet to see any sort of 1/4 mile results from either

gabe3d is close to having his completed soon (check his build thread) in a G35. We've got one that we've been working very slowly on for awhile (I think it was the first BC kit for an NA car they shipped), but I don't expect it to be done till ~ summertime, as it's way more than just an engine build

to answer your question, 100mm is the largest I have seen done

 

Yeah.. I'm not going to bump the stroke up.. I want to keep the rod/stroke ratio decent, so I can keep the piston speed (and cylinder filling) reasonable, at nearly 8K rpm. The C8 cams really shine up there, and it will only get better with a larger bore/deshrouding.

I'm going to call and talk to the guys at Darton, tomorrow, and see if they can offer any insight. Thanks!


Travis

 

are you going to have issues finding a vq piston over 100 mm??

 

Nah.. I have all of my pistons custom made to my specs. I use CP or Diamond..

I talked to Darton, yesterday, and they were saying that it's not a question of wall thickness/integrity, beyond 100mm. The issue is bore spacing, and the fact that you can't fit the firing rings for each cylinder if you go any larger. You simply run out of deck space to create an effective seal.

Oh well.. looks like 100mm is the limit..

Travis

 

You said that you had used 101mm in a previous NA build with no problems.
If wall thickness is not a problem with Darton then 101 bore size should not be a problem.
Cometic make 101 head gaskets. You would think that they would not produce a HG that would not seal.

 

I used AEBS sleeves at 101mm, which have a completely flat deck, versus Darton, which has a coolant channel recessed into the deck. I am just going off of what I was told by Darton. I'm not going to trash a 2K dollar block for 1mm extra.

Travis

 

What tires were you using on those runs? They seem to be sticking really nice off the line.