Which depends on what revs an enhanced DE can safely go to. For a DOHC design the DE is a low revver, a pushrod LSx can match it so obviously there are factors other than the valve gear which limit revs. Oil pump? pistons? crank? con rods? or is the DE basically a rev limited design, weak block? poor crank support?

I've done a fair bit of research on the DE here and elsewhere but other than part replacement eg con rods, pistons etc, have found nothing hence the topic. I'm just trying to work out if the DE is worth spending money on given how difficult it is to change to a later engine, besides I like a challenge. For a start block filling seems to be a good start but I've found no mention of that.

Please keep in mind that the question is about improving the rev red line of a DE for RACE CAR PURPOSES, it's assumed that the heads, cams etc are not the rev limiting problem and that the engine will be built to the best standard. What do we have?

 

Did you look through here ? (I'm not being facetious, genuinely heaps of info)
https://my350z.com/forum/na-builds-498/

Pay extra attention to Sasha's threads (SGSash).
I think over the last 9 months I've read every post I possibly could as I build my one, some are directly relevant to my build, others aren't but there's tons of info.

 

From what I've read, oil pump and gears are worth looking at.

 

Long story short, the DE is a solid motor. IIRC, it was designed a truck motor. Its got some design issues that are tough to overcome, but are not really necessary to overcome as you can still make power around the issues. The main item you brought up, rev limit, is slightly hampered by its design, but its not a huge problem because the engine can still rev plenty high to make solid power. For the DE, the connecting rods (bolts) have been seen as a limiting factor. I've pushed mine to 7500 after swapping the oil pump to a Rev-Up pump, changing the rods to Eagle, balancing the assembly, and upgrading the valve train. I'm pretty sure it could go higher, but its not making any more power so I capped it.

I haven't been following the newest stuff on the engine lately, but the block stiffening didn't seem to help the NA applications. The heads are seen as pretty good, the cams are definitely a little modest so a wild cam on a track setup can yield a little, and the engine is sensitive to headers.

Is it worth it? That's for you to decide. I love mine, but I can see someone saying its not worth it. If you're running in a class that 300-325 WHP puts you in a good place, go for it. But if you need 400 WHP its probably best to consider all options. Like RobPhobos said, check out SGSash's threads and see what the engine is really capable of with a large budget and a ton of good engineering.

 

At a min, if you plan on reving to 7K+ you need to upgrade Oil Pump, Valve Train, and rod bolts.

 

Thanks fellas, one advantage of the DE over later models I ran across is that it is significantly lighter which reinforces my intention to keep the DE and not go for more capacity. If big power was really the priority there is a new LS3 in the shed but that will probably go into the 280ZX 2+0.

 

The DE might struggle to breath at 7k+ just a little, Sasha was running ITBs but his setup was nice for sure. I've always thought of the sr20 being a better swap for the s30 chassis.

 

The Plenum and Cams are what hold the DE back at higher revs.

 

So if I have this right, over 8k revs needs a dry sump because oil pump, bottom end is good with the usual aftermarket con rods and suitable oil pump up to near 8k.Half fill block should help bottom end rigidity, standard crank cradle is OK as is the crank.

How does that sound?

 

You need don't need a dry sump to go to 8K you need Sucker Punch's Billet oil set up http://www.suckerpunchmotorsports.co...-vq35de-03-06/

Billet gridle highly highly recommended, there is a lot going on at 8K+ why risk it.

 

Excellent, I wasn't aware of that oil pump.

 

In summary then, if the DE is upgraded as discussed then it can match the later 3.5 versions in potential power? Giving a lighter but more expensive result.

 

The HR will always breathe better, what manifold are you running? If it's not ITBs you will have a hard time matching what a max bolt on HR can do, 8k won't make power of you just slap on better cams and leave the manifold intact.

 

The present exercise is to determine what revs a suitably modified DE will run safely too, no point in looking at improving breathing if the pump is not up to it. I would hope that a good port job with ITB's fed by 3" cool air intakes each side plus cams and springs would breathe to 8.

 

Ever thought about contacting JWT? I don't know of any limits with engine geometry when it comes to revving this engine out, but then again the only publicly known NA DE was Sasha's engine, I guess a better question would be how much power you want? Not sure if you have read this but I'll leave it here anyway.
http://www.superstreetonline.com/how...e-engine-build

 

Thanks for bringing that link up, I'd lost it so now bookmarked.

 

For the curious, aren't we all LOL, the engine file for the 350Z is still to arrive but it's DE engine is pretty well full race, Kelford cams, NISMO oil pump, some Brian Crower stuff, good rods and pistons, Haltec ECU with VVT enabled, headers, ITB's. Unfortunately for me the owner wanted lots of mid range power, the engine builder said there was another 50 HP available if wanted.

So you can see why the above questions were asked, particularly rev limits. As far as I'm concerned now, no HR or VHR required, DE is lighter too.