Hey guys,

I read the forced induction for noobs thread and its stated that the stock heads/cams can handle 700+ hp. I spoke with two different shops and one shop said that the heads have trouble making power over 500hp and the other shop said 500hp is the max? Can anyone confirm or clarify this?

Also, this is assuming the bottom end is already built so the engine itself would be built for 600rwhp.

Thanks for the help.

 

Yes, there are people running more than 500 whp. HOWEVER, from the research that I have done, the problem is in the main block. The tops of the cylinders tend to wobble at very high hp because they are not well supported where they meet the heads. It eats up the head gaskets. Cosworth had fixed the problem with their own blocks.

This is the stock VQ-35 block:



This is one that has been sleeved for high hp:



See what i mean?

This is one that has been closed off by welding and re-decking the surface:

 

Those shops are giving you bad info.

 

You might run a stock block on the street, but not on the track.

 

Wow! Thanks for the very helpful reply TexasScout. I never would have thought that the issue with making over 500hp would actually be in the block. I always thought you would just need forged rods and pistons. So, if I want to do over 500hp I'd need a sleeved block then? When you reference to 500hp do you mean at the wheels? If so, I'd be happy with 500hp at the wheels, which means I'd probably have to run close to 600hp at the crank right? That said, and correct if I'm wrong, if I have forged pistons and rods I should be able to do around 450-490hp at the wheels/540-560hp crank safely, and have no issues with piston wobble and blown head gaskets?

By the way, I won't be racing the car on a track. I have my car with me europe so I do a spend time on the German highways/autobahn and push the car to max speeds over 140mph for 10-30 mins at a time. So not really racing anyone, but driving high speeds for extended periods of time.

Thanks for the input.

 

Whoa whoa whoa. Jesus. First- go read the 45 or so pages of my build thread and you'll start to figure out what's in store for you at what I'm assuming your level of knowledge is (probably twice what mine was when I got into it.)

Second. If you're going over 800hp then MAYBE you're looking at sleeves. VQs do not sleeve well.

The heads do flow well but depending on which heads you're running- non versus revup versus HR they may theoretically be able to "hold" 700 but not generate it. Heads on a non revup right now pretty much held me to about 520 realistic to the wheels. Could have probably massaged a bit more.

The rev ups seem to do a bit better- 550 or so with the same effort on the tune and the HRs probably a similar bump up from the rev ups- maybe more?

Heads on these cars do not swap in and out easily- so if you're building the block just go to Dynosty and get one of their long block packages that support your power goals (or slightly exceeds it- you know how it is!)

Forget about sleeves. At 600HP it shouldn't even enter your vernacular.

I've still got my stock heads... But knowing what I know now I wish I'd dug in just a wee bit deeper.

 

I think that's about what I said. 500 RWHP is doable on a stock block and heads. If you want to go into Supra territory, then you gotta dig DEEP. I'm just passing on what I have read hear and other places about the problems with FI and the VQ.

Personally, I think you would be money and time ahead by doing the LS1 swap. There have been enough done now for it to go fairly smooth.

Also, don't for get to look on My350Z.com, there are MANY more guys that have FI there than here and most of what they have learned applies here.

 

The ls1 is an option talked about but seldom reported to be smooth- and I think op has some reading to do both through these forums and my350z before any of this is more than a faint blip on the radar of reality. You don't just slap an ls1 in there and walk away with 550...

The stock revup block is good to ~500- when properly supported. Some have taken it farther than that and driven it hard TO blow it so it could be built... And some even fair well. If a guy wants in that neighborhood he has some reading to do on what supporting mods he needs and ls1s and sleeved blocks aren't two of them.

Look up the boosted performance single turbo provided a kit exists for your platform and choose the turbo that suits your goals. Easiest kit on the market- according to many, many experts and laymen alike- to install and upgrade.

 

Theoretically yes, but that depends on how well its put together and tuned.

 

Probably the most important.

 

Hey guys,

Thanks again for all the replies.


ITNKICN -

I plan to check out your thread and see your build. I appreciate the lead.

I need all the guidance I can get. I have done a lot of research and I feel like I spend most of my nights on this forum. I wish I would have been more into modifications when I purchased my car almost 9 years ago. I was really happy with the stock G, and having it in Europe is a rarity over here. I've been a forum member for a long time, but I haven't gotten into modifications until the last year or so. Anyway, after so much reading on my350z and here, it gets to a point, that you need to take a break. Sometimes it helps to have someone reply directly to a post.

I don't plan to do anything like 800Hp or something extreme like that. For me 500rwhp is way plenty for what I want. I just want a reliable FI built engine.

TexasScout -

I've considered going with an LS2 swap actually. From what I've read, 500whp is not realistic with an LS2 swap. More than likely I'd have to do much more than just a swap to the numbers I'm looking for. The other issue is that I'm working with shops in the UK so it may not be as familiar for them. The G is already unfamiliar for the UK. I top nissan skyline tuning shop in the UK have never seen a G35 coupe until my car showed up one day. So, I want to keep it simple so it won't be a huge challenge for the shops here.

I did a lot of research already and I have learned alot from what I've read. I was recommended to buy a GTM supercharger kit by the a prestigious UK tuning shop here in the UK. They have had good results with these Rotrex based superchargers. I've read posts on the UK 350z site and it seems that the shops here don't like to do turbos, thus probably why they recommended a supercharger. Unfortunately, the GTM superchargers just came out this past summer 2012, so not a lot of people are running them yet.

ITNKICN - I think you are the one that recommended Dynosty to me in another post of mine. I actually called them yesterday and spoke to Dustin. I emailed Hal on what I'd like to do, so I'm just awaiting their reply. I wish they had their parts website up and running, but its still in the works. Also, I will look into the single turbo. I'm just worried about the turbo lag in the G. If running forced induction, I'm sure the compression rate is around 8:8 or 9:1 so it wouldn't the G be even slower until reaching that particular rpm where the turbo kicks in? I'm also under the impression that the guys here in the UK want to stay away from the turbo. Also, I could be wrong, but it seems that going the turbocharged route would be more expensive, especially when you add all extra supporting mods right?

Thanks again for the help.

 

Yes, but it only takes seconds before a turbo spools.

Turbo setups are more expensive. If the torque curve of a supercharger is enough for you, then go that route.

 

Herrschaft -

Thanks for your reply. From the looks of a supercharger torque curve, it looks plenty for me. So for now...I still intend to stay the SC route. You are also probably right about the turbo spool. I figure that running a lighterweight flywheel would help with that, but then the car might always be in "boost mode" and the driveablity factor could decrease.

ITNKICN -

I'm at page 15 into your thread. Your writing style is very interesting and entertaining Still got a long way to go before I get to the end of your thread though. What I am learning so far is that it's probably better for me to stay the SC route. The turbo setup seems to be problematic. I will comment back when I get done with the thread.

 

Just so you know... 350Z_T / Sasha is Boosted Performance... so when I reference him, that's the kit I'm talking about. He goes by "Boosted Performance" on my350z.com. Definitely worth a look.

 

Well ITNKICN,

I read through your entire 45 page build thread. Actually, I've read parts of it before so it wasn't so unfamiliar. The reading was entertaining at times, but only in regards to your writing style. I have to state that your story was a real rollercoaster ride to say the least. The worst part had to be the end where you had to pay the fine. I can't even imagine how much money you spent on the whole project. I did learn a few things from your story though. Some things I planned on anyway, but your story helps me confirm my choices for my future build.

I've had my G since 2004. Cost $40K new and I've been happy with my car for the past 8 and almost 9 years now. Odometer is at 166K so I don't think it would be a good idea to go forced induction without a build or built engine first. From reading your story ITNKICN, it seems like a built long block would be cheaper to begin with. My issue is all the work to get heads and block re-finished and any other areas of the engine that need to be addressed before re-assembly.

I pretty positive the supercharger route is the safest/cheapest way to go. The power of the SC won't be anything like that of a nice TT set-up, but I'm ok with that. Having a completely stock non-rev up coupe now, and going to a built engine/SC coupe will be a huge difference to me. I don't think any superchargers on the market can surpass 550 at the wheels so stock heads should be fine in my application. I'd be good with 450-500 at the wheels, maybe even less. From other threads it seems that the SC'd route is cheaper as well.

To be honest, the GTM SC kit is the most expensive I've seen so far. From further reading, I'm not sure about the value for the price they are charging. I guess even the guys in the UK, which recommended to the GTM site for a supercharger, mentioned that the GTM kts do not put out the power that they advertise. So, apparently its not an unknown fact about GTM kits not putting out what they advertised. That being said, the vortech could be the best option. My only issue is that if I'm going with a built engine, wouldn't it be wise to maximize the benefit of having a built engine and to try and get all the power I could get? That is, up to 450-550 hp at the wheels. I'm doubtful the vortech will achieve those type of results without severe strain on its system.

I emailed Dynosty and they've sent me quote in the upwards of $20K. That is with a turbo though, since that seems to be their choice of force induction. I'd have to add at least another $5K for international shipping and installation. Seems way more than I want to spend. I really like my car, but its valued between $8-10K right now. I need to figure out the cheap but smart way to do things. I don't want to spend $25K on just parts and labor for a 9 year old car. Anyone can chime in if you have any advice. Again thank you to all those that have offered advice so far.