I see alot of talk about people adding blowers and turbos to their G. How safe is this on the stock engine? Can it be done AND be reliable w/o going into the motor?
I know with my LT1 Camaro it is not a good idea with the stock compression, too easy to blow the motor.
Whats the deal with these Nissan engines? Daily driver safe?

 

I'd be interested to know too. Any gearheads out there willing to share? Thanks!

 

i know a guy in Japan who's pulling 350whp on his 5AT. his motor's fine but
his tranny was replaced after about 10km. hehehehe.

 

It can be done safely, but you MUST keep the boost low. The stock compression ratio is 10.5:1, which is high for a forced induction application. Adding boost of course increases the effective compression ratio, and detonation is a concern, usually dealt with by richening the fuel mixture under boost and changing the timing. So proper tuning is essential.

Also, the stock internals aren't good for much more than 350-400 rwhp. Sure you can go higher than that for a while, but it WILL break - just a matter of time.

In order to do a VQ35 right with boost with reliable serious horsepower, you need to spend the bucks and have the motor pulled, go with all forged internals with lower compression, and have the block decked and reinforced.

If you go the cheap route and run the stock internals, make sure you keep the boost low, and make sure you've got the tuning perfect.

 

^^^^ what he said

 

Yep, what ZO6 said. There are many, many people these days getting these "bolt on" kits for forced induction (turbos, superchargers) who think they can just bolt on and go. Yeah, maybe for a few hundred miles. The right way to do a FI engine is to lower the compression to at least 8.5-1 with dished pistons and forged internals due to the increased pressures and stresses on the internals (con rods, etc.). Bottom line? Don't do it unless you want an unreliable and soon to be replaced engine. A properly done FI engine will run you anywhere from $6-8000+ in addition to the labor (if you don't do the work yourself). A brand new, fully blown engine can run as much as $20,000 with all of the goodies.

 

There are several people that have been driving around for 1 year and 20K miles with TT's or S/C's and have not had any problems. You will be fine if you keep it under 400rhwp and pull enough timing plus get the a/f mixture right.

There is not much info on this board about FI. Go to my350z.com and looking in the FI section. Tons of info compared to here.

 

Go over in the FI section and ask these questions, you get different anwsers!

 

Got it, basically the same deal with the LT1. I figured but wanted to check cause it seemed like adding a supercharger/turbo was pretty popular but it didnt seem like a bright idea to me on a stock car/motor. Too bad too, it limits the car to ~300hp without going into the motor and spending $$$

 

Yep, it may run fiine for a while, but, trust me, the engine's longevity will be significantly reduced. If someone is going to do a turbo or supercharger, that person should not do it half a$$. Do it right, and ask anyone who really knows about engines, and they will all tell you the same thing... don't run anything over 8.5:1 compression.

 

Respectfully, I disagree with the notion that you have to go to 8 or 8.5 to 1 compression pistons and then work up from there. That is an old adage, and a good one, of using low compression and high boost, but it stems from the old Detroit V-8 iron. Yes it made sense on those blocks, indeed still does.

But there are trade offs. Low compression gives really lousy low end response on turbos and centrifugals. But in the "old" days folks were running positive displacement (roots/eaton) blowers, that come on strong at 1500rpm and are all done at 3000 rpm. The centrifugal blowers come on at 3000 and run hard to 6500 rpm or more. By using a centrifugal off a VQ35DE motor at modest boost you can have plenty of power (360rwhp and 330lbft torque) and smooth streetability. My ATI Procharger has given 20,000 miles of trouble free joy, including more than 8 full blown track days at Sears Point, Laguna Seca, Big Willow Springs, Buttonwillow, and California Speedway. She runs sub 1:50 times at Laguna Seca, and sub 1:45 at Big Willow, and sub 2:00 at Cal Speedway with a very sub par driver (me), so she is fast.

BUT, you have to be very responsible. Do not push more than 7lbs of boost if you run stock guts. Do get the car very carefully tuned and watch the A/F mix religiously. Do maintain the car scrupulously. If you get greedy for power or sloppy you will blow it up, as you will any motor.

Back to the compression issue. The modern engines have alloys and strength that are completely different than what was available 20 years ago when the low compression/high boost mantra made sense. Now there is more to be achieved with something other than that. You can drive around below the boost level in a centrifugal and enjoy the power of the stock compression, and then draw on it as you dig into the boost above 3000 rpm. It is a performance profile that kicks the butt of the old approach. Now...if you want to go for even bigger induction, you do have to rebuild the motor, and then you have to be careful. Think about this. How much rwhp do you think you need and can practically use? Getting over 400, and certainly to 500, not only reduces your engine life and reliability....but it becomes very hard to hook the car up, and you have to start fussing with your driveline etc. Plus you are flirting with having to go to very expensive fuel blends to avoid early detonation disasters. For a road racer and daily driver, you don't need it. The additional money is better spent on suspension and handling mods.

The lads that design and make the kits...lets give them some credit here. They have the outline to deliver a powerful product that does not require building a motor or using rocket fuel. They keep it well within that. WE are the ones that get stupid and push it past the envelope and blow it up, at least most of the time. Do the research and learn and improve your knowledge before making any choice on this. If you understand what you are doing, you will not make a mistake.

In any event, for a large number of people, FI is not a good idea. But if you are responsible and careful, you can do it, and it is an awesome experience. The shrieking scream from your little V-6 engine as you blow past a Z06 corvette on the track at Sears Point is something to experience and enjoy.

http://www.g-owners.com/article_imag...ears_point.wmv
But it is for many fewer than try it.
Cheers
Ed

 

Sorry, I cant agree with all of the statements. Currently there are plenty of VQ35's running well over 400whp on stock internals with no problem. Actually there are a couple that are running at 500whp and have not blown. The internals aren't as weak as people perceive them to be. The current APS Twin Turbo set up comes at a conservative 8psi for the stock map. The JWT TT will be coming out at 6psi but puts down 412whp judging from the graphs on their website.

Before boosting other issues need to be addressed than just internals. Even if you have forged rods and pistons, the Crank Angle Sensor needs to be addressed as well as Oil starvation.. I may be wrong but I believe this can be attributed to some of the blown engines that we hear about, tuning is a big issue as well.

There are owners who have boosted up to 10 psi, torn down their engine and found that everything was still in tact and in perfect condition. With that being said, you are still taking a big risk when modifying so always plan for the worst.

edit: In no way am I saying that our engines are bullet proof and will last forever when boosted. I am simply stating that these engines are not as bad as everyone perceives them to be.

 

Not saying that this is safe, but this guy is running 505rhwp on a stock block with an APS TT. He is going on 6000 miles with the TT and the car has like 14,000 miles total.

Link to 505rwhp on stock block

 

Yep - so many engines are coming from the factory these days that are pushed ot a high state of tune, high output-per-liter, and (therefore) high compression ratios....

Good for factory performance (80,90,100 HP per liter) but not as good for aftermarket FI applications without lowering that compression ratio some....

No matter what, truth is... lower compression is safer for the longevity of a streetable, daily driver FI application.

 

Not bad, but I was running 1:47's all day at Big Willow with my bone stock G35. I'm a decent driver I suppose, but I don't have much experience - this was only my second track day, and my first with the G35. I know I'm leaving at least another 5 seconds on the table that I can pick up with more experience and some high performance driving school.

The issue is detonation. Modern engines with aluminum alloys don't mean squat if you got detonation problems. Hell, you can even fry the most expensive forged racing piston with detonation. And cast iron blocks usually make the best platform for forced induction because they are stronger than aluminum alloy. It's one of the reasons the Supra motor can handle so much power on the stock bottom end. People think its magical, but its pretty simple really: cast iron block, forged internals, low compression ratio for high boost. That's all there is to it.

You can avoid detonation in a high compression engine to some extent with large intercoolers to cool the intake air as much as possible, and by running very rich under boost - the more fuel you dump in, the cooler the burn. High octane race gas is another help. But again, you can get the power levels up with the stock compression, but the rest of the motor can't take the added power and you run into problems with the rods, crank, pistons, block, heads, etc.


A bone stock Z06 puts down 353 rwhp and 340 lbs. of torque, and weighs 350 lbs. less than a G35. Bottom line: the only way you will "blow past" a Z06 at a track with your 360rwhp G is if the Z06 driver doesn't know how to drive.

I blew past a 911 TT at Big Willow in my Z06 like he was standing still when my car was still stock. Did the same with a '99 Viper with a head & cam package. Does that mean my Z06 is faster than both of those cars? Absolutely not. Both of those drivers were absolutely terrified on the track, while I was blasting around the track taking my chances and having the time of my life. If I had a video camera in the car, it would have looked really impressive: me in my Z06 blowing by both a 911 TT and a modded Viper like they were nothing. But you won't see me bragging that I blew by those cars and saying my Z06 is faster. Because I know the Z06 is dead equal to the 911 TT on the track, and slightly slower than the modded Viper, although easier to drive at the limit.

To give you an idea: bone stock Z06's at Big Willow run 1:33's with good drivers.