I had a GTI 1.8T that on the stock 9.5 compression put out 370whp on 93oct and 425whp on 109oct and never had an issue. Considering that this engine has no variable valve timing ( other than for cold start emissions ) and is only1.8L spinning to 7K rpm...can anyone see anything wrong with a VQ putting out 500whp on 11.5CR with 109oct fuel...or maybe even on 93? It is certainly a better breathing engine ( the 150hp 1.8T has a similar hp/liter rating as a VQ even though the 1.8T is turbo running at about 8psi ). Has anyone even tried it?

 

heres something close. https://g35driver.com/forums/nationa...ne-please.html


JWT TT 700BB Kit
Wiseco Pistons 96mm/11. 0 : 1 Pistons
Eagle/SCAT H Beam Rods
ARP Rod Bolts
Block inspected and cleaned
Block redecked
Block Bored and Honed using a Torque Plate
Rotating assembly balanced
Crank magnafluxed and the journals micro-polished
New Moly coated Race Spec main bearings installed
New Moly coated Race Spec rod bearings installed
Block assembled
New OEM Head Gaskets
Heads inspected and cleaned
Heads redecked
Ported exhaust and intake runners
Oil Pump - VQ35 RevUp
JWT S2 Cams
JWT Heavy Duty Valve Springs
5 angle radius cut valve job
New OEM Valve stem seals installed
Valve Stem Heights set
Cold Clearance set for stock cams
Heads assembled
New OEM Rev-up Oil Pump
ARP VQ35 Head and Main Stud Kit

 

Stock compression is 10.3:1 So if your building the motor to be 11.5:1 why not build it at 8.5:1 or 9:1? A better compression for a turbo. On the stock 10.3 though you can put down about 400 at the wheels safe...ish. In this section read forced induction for noobs. It has a TON on great info.

 

+1 if you build go lower, not higher compresson. With low compression, better rods and bearings you should be very safe at 500whp with a proper tune. You will eventually blow a higher compression motor, and/or burn your valves or melt your plugs. If you do decide to go with high compression, you better keep your boost level way down, like 5psi or less.

Rule of thumb:

NA = go higher compression
FI = go lower compression

 

Rule of thumb is the norm ,not necesarily the best. I try to steer from the norm...lol...BUT, I will admit that if people have already tried it and failed miserably then there is no reason for me to do the same. On the stock block people run about 400whp because the rods snap, not necesesarily because of the compression. The link posted on top was apparently a rod sizing error?

I'm probably looking more into running a S/C but would like as much low end power as possible and higher compression will give me that. Higher compression will also allow me to run a larger pulley to make the same power at less boost which should help with belt issues.

I'm not looking for 700-800whp, for which I would definitely go with low compression, but I don't see why 11.0 or 11.5 shouldn't be okay on a forged bottom end at 500whp and moderate boost.

Heck, if the bone stock HR can get away with ~500whp on the stock 10.6 compression then I don't see why the same power can't be put down on on .9 higher compression with all forged components. Heck, the VQ37VHR gets away with 600+whp on stock bottom with 11.0 compression.

I'd be running cams to aid in the breathing department fwiw.

I know it apples to oranges but a bone stock S2K can put down over 500whp on the stock 11.x compression on a 2.0L 4 banger. YIKES!

 

This is not a bad idea. I initlally went with a 11. 0 : 1 setup because I was looking for what you are looking for. Low fives with low boost..... If you have everything to support it, you should be fine. My build for this motor didn't work out because of certain things.........

Good luck.

 

I would not run boost with that high of compression...like others said if you are going to build it might as well run low compression pistons. Look at it this way...how many times do we see boosted cars from the factory run high compression pistons?

As far as boosted VQ37HR on stock block reaching 600WHP, well one thing you have to understand is that the VQ37HR is a completely different animal than the VQ35DE. On the other side, while they may be hitting that number...how long will it be reliable?

 

You could do it but the tune has to be very good and I'd think you'd have to run a pretty high octane gas

 

Well, oem tunes are made to be SUPER conservative. They tend to run overly rich and lowering compression just ensures extreme life expectancy. They also don't tend to run forged pistons and rods.

The new Ford Taurus runs 10.3:1 and 12psi of boost. The VW/Audi 2.0T runs 10.5:1.

Considering I'd be using superior parts than the oem and would have a better tune, I don't see a problem. Maybe I'll go with 11.0 instead of 11.5...but has anyone done this ( other than seung012 who unfortunately had unrelated issues )?

 

+1000


OP, since you are building a boosted motor, why do you want to run such high compression? What do you expect to gain?

Do yourself a favor, and spend alot more time researching the subject. There is alot more information available on the My350Z forum, so you might want to start there. Also, find an experienced tuner to guide you with your build. Based on your posts herein, you have made it abundantly clear that you are getting in over your head and you are going to be in for a big let down.

 

If one more person posts that 400wheel hp is safe im going to delete my account.

 

400whp is safe

 

Just because the stock VQ breaks at ~400whp doesn't mean it has ANYTHING to do with the stock compression. It just means it has weak rods. No reason to keep bringing it up.

Great engine response ( especially at the lower end ) and good power at the lowest boost possible. The VQ is WEAK down low and I want it to respond better, especially since I want to supercharge it which makes the low end weakness stand out more.

I'm not exactly a noob at this...I'm a noob for the VQ but not for forced induction. The one thing that has been consistent from forum to forum ( whether it's been VW, GM or Inifiniti is that people assume SOOO much that things originally taken as a "rule of thumb" all of a sudden become FACT and no one dares to challenge it.

I tuned a turbo LS2 that put out 500+whp on 93oct on the stock 11.0:1 compression and it has been working flawlessly for years.

On my GTI I was always criticized because I wanted to make big power on the stock turbo software using a crappy ( and free ) software called lemmiwinks to change some settings on the ecu and a larger maf with larger injectors. Everyone ( and I mean everyone ) kept saying that I was going to blow up and blablabla...well 425whp later I never blew up and even had a few people doing the same thing after I did it.

I also tuned an Audi TT the same way I did my GTI and he put down 528whp with no issues as well. The same way everyone said I would blow my car up.

When I had the Grand Prix I wanted to turbocharge it for under $3000 and everyone said it would run like crap and be slow. I ran 12.6@111mph on street tires, near stock exhaust and stock engine and the car was my daily driver with ZERO issues. I also said that I didn't feel the need to rebuild the transmission just because I didn't want to pay any more.....well everyone kept saying that I was going to blow my transmission within the first week and guess what? I ran dozens upon dozens of mid 12 second passes and not once did my tranny grenade.

I don't want to hear people say "it won't work" or "your going to blow up" without having the FACTS put in front of me. I want real life stories and want to read about other people who have tried doing the same and have failed or succeded.

Please...no more negative thoughs without backing it up. Give me the FACTS! And if the FACT is that barely anyone has even tried it...then that is FACT!

 

Why don't you just search for yourself in the tech area. Tons of info on here and my350z.com

Heres a head start:
https://g35driver.com/forums/forced-...-you-push.html

 

I have and I still am...but I haven't really found anyone that has done it. Í'm still reading. I've read the link you posted before, but stock engine doesn't concern me for the reason I posted above.

I thought with posting it someone here could point me to better topics or enlighten me with EXPERIENCE with high compression and forced induction on the VQ. I guess this is almost kind of unheard of?