Hello all, I was hoping to upgrade my engine internals in order to squeeze out as much power as I can out of the 2UR w/o going forced induction. Does anyone know of anyone that manufactures aftermarket cams, heavier valve springs, pistons to increase compression…etc. Has this platform seen any gains from porting and larger throttle bottles and whatnot? Thanks for everyone’s input, if I can get the parts, this would be a fun project.

 

The short answer is no to all the above. This isn’t something that we have seen power increases from, and it’s far from worthwhile when cost is considered. It’s cheaper and easier to swap in a newer Gen 2UR and run an e85 tune for more power.

 

Thank you, would something like stiffer springs atleast help reduce flutter and allow me to redline a little bit higher?

 

No because we can’t flow enough air to benefit from higher rpm outside of avoiding a final shift at a drag strip. The tunes allow 7200 rpm shift, but power isn’t increasing at those ranges. It plateaus or falls. There are no aftermarket cams to address that.

 

What would an aftermarket cam need to posses in our cars in order to benefit from an increased redline and stiffer springs?

 

simple not helpful answer: more lift and/or duration

correct but also not helpful answer: Thats a question between the customer and engine builder/person cutting the cams. It depends on where you want to move the power band for your application

 

This is ultimately a very complex task that nobody has done R&D on. You also have to look at mean piston speed and determine if the bottom end can survive at higher rpm. We have discussed mean piston speed in another thread. We found some data to suggest that 7200 rpm is ok, but even then it is reducing service life. In the end, this would take 10s of thousands of dollars, If not 100s, to find if optimal results exist for new cams.

Your options for power are:

You can bore the engine. I believe Novel has, and there is a 5.6L GSF running around social media with that engine. His is built with an upgraded lower end, but I don’t recall any changes to his head. He spent a pretty penny getting the engine. Their MSRP on it was steep, but I’ve since forgotten the number. I’m recalling around 15k, but don’t quote me.

It’s cheaper to supercharge, but we have seen mixed results with that. I’d recommend a willingness to build the bottom end if you do it. Some people have cracked ringlands, but some have had no problems at all. We used to believe a healthy engine with good compression can take boost, but then a member with healthy compression cracked ringlands as well. He had his bottom end built afterward. I think he then sold it.

There are some reliable boosted ISFs out there. YMMV.

If you pay a shop, I believe your looking at close to 5 figures for building our engine. That’s what I’ve been told by people that built them.

You can do a custom turbo kit, but see above. Same issues exist as SC.

RR has played with throttle bodies and found no substantial gains.

A tuner is in development on an E85 tune that will probably yield the highest NA HP possible. E85 GSF/RCF are laying down around 440-460 whp. But 430-440 whp dynos can be found on e30 and 93 octane… so we’re not talking massive numbers here. The RCF and GSF also have much higher fuel pressure than the ISF based on the HPFP, which cannot be swapped onto an ISF… so who knows how that will go. We haven’t seen dyno numbers yet. It will require fuel system upgrades, and is not a variable tune. You will get e85 only.

So yeah, the car can reliably make around 500 hp at the crank with bolt ons. The cost/benefit ratio of building it is not there past bolt ons. You can boost it, but do so willing to build it, and your going to be all in with boost and a build at between 20k and 30k plus if you go with off the shelf parts and shops.

If you want something that makes monster power, the 2UR is probably not your engine. If you want something that makes moderate power and is fun to drive reliably, throw some headers, exhaust, and a tune on it and enjoy it. Making it lighter can go a long way, but is equally as expensive. I have some lightweight goodies, and while they help performance, they didn’t turn the car into a GTR killer. My car runs low 12s.

 

You seem convinced stiffer springs are necessary. Why?

 

I've been through this. Worked with Rafi during my engine rebuild - there is no part you can simply replace internally in this engine that will give it a wild substantiated increase in power.

If you really want, replace pistons to increase compression, but that will just put you right beside the power output of an RCF.

I decided to go OEM rebuild, FBO + Tune. Couldn't be happier; I was planning on going supercharged - but won't be doing that anytime soon. 420+ WHP is enough for me to catch competitive lap times at the track

 

Did you end up replacing pistons with an aftermarket company or did u stay with OEM? Do you know if there’s anyway to hit 500 WHP while staying N/A?

 

Stuck with OEM pistons.

Only way to get to 500WHP, N/A is: https://dsportmag.com/the-cars/club-...gse-sema-2016/


And I don't think they even hit 500WHP

 

Awesome thank you for that, will definitely look into that, I don’t see why I wouldn’t be able to if I also blend fuel and go full bolt on (headers, exhaust, etc)
Thanks for your help!!

 

You're welcome. If you pursue it, success or failure, be sure to document and share!

 

Oh I think that’s the engine I mentioned above. I thought Novel had built it. Someone on Instagram bought that engine and it’s in a GSF now.

It is the same. He is now stage 2 RR supercharger and didn’t state numbers other than less than 700 whp. I never saw NA HP numbers.

 

I believe you're correct! I saw this on ebay while I was cruising options for my F - it wasn't a plug and play for my application and it was very $$$$.

In anycase, I think they floated around 525HP for the publication, but I too never saw WHP numbers or N/A Dyno numbers.