Advice on turboing my 350z.
Advice on turboing my 350z.
I just got my 2004 350z not too long ago and it's got exhaust and rims but I want to do more performance type work considering all my friends have wrx's, my z is quick but not enough to beat them, I need advice on what I could do performance wise to make it faster, such as turbo or tuning. I can get up to 10-15k to spend on it.
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mrwoodsauto
- Posts: 16
- Joined: Sun Aug 10, 2014 7:51 pm
- Car: 04 G35
Re: Advice on turboing my 350z.
Before you go blowing $10K - $15K on the car and trying to make it faster know that you are in fact:
1. Never going to get back the money you invest. It's impossible. A turbo kit won't add that much more value to a car when you go to sell
2. Reliability becomes an issue since you are now boosting a motor that was not originally designed for boosted applications.
3. You should consider transmission upgrades prior to power upgrades.
4. Take the car to the track and learn how it handles. Just because you want to dump money into it doesn't mean that it'll drive better. Sometimes it's the driver that needs to learn the full potential of the car first.
Here's what I'd do.
1. Valve body upgrade from Z1 or Stillen (both do a good job)--> shifts will be much smoother and you'll get more torque
2. Look at GTM for upgrades as well for cooling the transmission (they provided a lot of parts for me over the years) *upgrade the torque converter for automatic*
3. Get cams installed, that is will be a great 10-15 whp right there.
4. Keep the car cool. The engine is running at its best at cooler temps. A turbo kit will cause excessive temperatures. Not extreme but noticeable for sure.
5. Consider good suspension mods prior to power, because all that power with body roll isn't a good thing. You'll sometimes find that factory power with a solid suspension is better than anything else.
One of the guys wrote this article which is a really a good read. I've boosted my share of cars in the past and I've decided to stick to NA builds with meth injection. It's safer and more reliable than a boosted car which has no motor work.
1. Never going to get back the money you invest. It's impossible. A turbo kit won't add that much more value to a car when you go to sell
2. Reliability becomes an issue since you are now boosting a motor that was not originally designed for boosted applications.
3. You should consider transmission upgrades prior to power upgrades.
4. Take the car to the track and learn how it handles. Just because you want to dump money into it doesn't mean that it'll drive better. Sometimes it's the driver that needs to learn the full potential of the car first.
Here's what I'd do.
1. Valve body upgrade from Z1 or Stillen (both do a good job)--> shifts will be much smoother and you'll get more torque
2. Look at GTM for upgrades as well for cooling the transmission (they provided a lot of parts for me over the years) *upgrade the torque converter for automatic*
3. Get cams installed, that is will be a great 10-15 whp right there.
4. Keep the car cool. The engine is running at its best at cooler temps. A turbo kit will cause excessive temperatures. Not extreme but noticeable for sure.
5. Consider good suspension mods prior to power, because all that power with body roll isn't a good thing. You'll sometimes find that factory power with a solid suspension is better than anything else.
One of the guys wrote this article which is a really a good read. I've boosted my share of cars in the past and I've decided to stick to NA builds with meth injection. It's safer and more reliable than a boosted car which has no motor work.
Re: Advice on turboing my 350z.
I already know that upgrading it won't bring the value up, I plan on keeping this car and working on it, I love the 350z, probably one of my favorite cars. I need to know what engine upgrades I can do to prepare for a turbo and what the best turbo would be for it.
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jerryd1987
- Posts: 182
- Joined: Sat Aug 06, 2011 9:25 am
- Car: 03 350z many mods inc next year
Re: Advice on turboing my 350z.
what sort of transmission? auto or 6mt? if auto sell it now and get the 6mt. the auto is going to need at least a cooler, valve body upgrade and torque converter. a jwt clutch will work in a 6mt for a 10-15k budget, then if you ever want to upgrade down the road just get a better clutch the transmission itself requires no upgrades. however the auto on the other hand even with 4k for a fully built one will start slipping the clutchs inside it around 550 whp. keep in mind you wont make that with a 10-15k budget plan more on 400 supercharged 450 turbo.
second stay away from GTM, last i heard they where going bankrupt. even if they arnt they are notorious for destroying s***, never have a engine built by them, dont trust any transmission parts with their name on it, and if you buy a turbo kit expect it to take several months to get all the pieces and dozens of phone calls IF you even get everything at all.
second despite what the above person says dont touch cams, your going to spend extra money for no reason, cams dont actually make any power, they shift at what rpm the engine makes power(aka torque) and enable greater hp through rpms. greater rpms on a engine means more wear from increased movement and additional heat. a extra 1-2 psi of boost is FAR better then a extra 300-400 rpms. lets not even start on the harmonics and cavitation issues the oil pumps are known to run into with increased rpms on these engines. the whole concept of "but you make the same power on less boost!" is correct, but you dont always want less boost with modern turbos and billet compressor wheels,plus like i said less heat from a little more boost. dosnt matter though because your not going to reach that level without a built engine. as an example i make 850 whp at 32 psi of boost just fine on stock cams, 600 on 20 psi, the only reason the engine is going to get cams is because i am building a custom turbo kit with tuned exhaust manifolds and custom intake with tuned runners and im matching everything to extract every bit of power possible out of my precision 6766. a supra made 1017 whp on one i wanna see how close to that i can get, other wise i would keep stock cams because they provide greater torque down low and are more "fun".
also the above user is incorrect in a turbo kit will cause excessive heat. the heat generated for a given power is the lowest with nitrous followed by turbo, then na, and finally supercharger. why? NA builds power through two things, VE and rpms. the VE on the vq35de is nearly at its practical limits as is, your not going to improve it by more then 1% without some very very expensive parts. so that leave rpms, which require cams to send the torque peak very very far right. When you do this the coefficient of friction remains constant on the bearings, as does the size of the bearings. each rod bearing is about 2.1 inchs by .79 inchs, mains are about 2.4 inchs by .79 inchs. so that gives a surface area of about 5.2 square inchs for the rod and about 6 for the main with some rounding. multiply that by 6 for rods gives 31.2 inchs, and 30 for all 5 main journals, or a total of 61.2 inchs traveled for one rotation of the crank. if you make peak power at 5k rpms this means as far as heat generated from friction the surfaces are traveling about 306,000 inchs compare that to 6500 rpms and you get 397,800. that is a massive change and easy to see why the higher rpm limit sees greater heat imparted to the engine and oil. while a turbo generates heat also ive actually logged temps previously at various parts of my oil system, full 32 psi boost, 30 minutes non stop, 85 degree day, turbo oil inlet temp was 179 degrees, outlet 189, temp by the time it reached the engine was 182 and my main engine oil temp sensor was reading 181 peak before dropping to 170 and holding constant because the oil cooler thermostat opened. so the extra heat going into the oil is negligible. especially since the bearings are seeing about a quart a minute and theirs 9 of them but the turbo only sees about half a quart a minute for both bearings if journal bearing.
^a bit long winded but basically any engine if everything else is the same, displacement, oil type, clearances, same power output ect. the only difference being one makes the power through lower rpm and turbo and the other na requiring higher rpm, the turbo engine will always be the cooler and more reliable engine.(i didnt even touch on harmonics and the weakening effect it has on metals)
also to take into consideration, sg motorsports spent over $20,000 into a 3.5L vq35 and "claimed" 372 whp(he sold the engine and the new owner couldnt even hit 330 without changing anything, on a different dyno and his drag strip times verified it was a low 330 engine) a turbo setup will cost half to 75% of that and make a a definite 420-450 whp reliably depending on the dyno.
finally the suspension, the suspension on the 350z is VERY good as long as parts arnt wore, which the car should be in good operating condition before any modifications. unless you have over 10k to drop on JUST suspension then you dont have enough to worry about that currently. for the average driver you will see 10x more benefit just putting a good set of tires on the car then the best suspension setup money can buy.
not sure why he would suggest meth and NA, but meth dosnt make the engine any safer it actually makes it more dangerous, first most injection systems are primitive so you really dont know how much your injecting, next few systems have any way of notifying the engine computer if theirs a issue with the system and those that do require a aftermarket ecu to actually do anything about it, and third all meth does is increase octane some and decrease iat some, as far as na with a stock block is concerned you will see essentially no benefit as far as iat is concerned, it works just like water with heat differentials, it provides the most benefit when the iat is far hotter then the methanols temp. IE boosted. as far as octane you will get some benefit in increased spark if you use it, however it will be heavily dependant on how much you inject. for the average person it wont even be enough for a single degree of timing. you would need to be injecting about 12% total fuel as 100% methanol to see a major benefit, which injecting 100% has its own safety concerns even i make sure what i inject has some mek in it if im injecting that so it at least burns blue instead of clear if a fire happens. if water is mixed in then you get more benefit in the combustion chamber effectively increasing octane a bit more at the cost of less benefit to iat's however then you are also using up cylinder space with something that is neither air nor fuel effectively reducing the VE of the engine and making less power. while spark timing can be increased the overall effect will be close to null.
your best bet for your money amount is get a good set of wheels and tires, dosnt have to be the most expensive, you dont need volks, tons of track guys run enkei rpf1's, tsw interlaggos, and tsw nurburgrings. a jwt clutch setup with a resurfaced flywheel if you can find a shop do it or a southbend clutch/flywheel combo for a little more, and a boosted performance turn key mid mount that comes with osiris, fuel pump, and fuel injectors. this will set you up for down the road if you decide to build the engine you will only need to change a few parts as his base kit supports 400-600 whp and his numbers are conservative(likely more since precision released the gen two 6266 which now supports 800 hp.)
second stay away from GTM, last i heard they where going bankrupt. even if they arnt they are notorious for destroying s***, never have a engine built by them, dont trust any transmission parts with their name on it, and if you buy a turbo kit expect it to take several months to get all the pieces and dozens of phone calls IF you even get everything at all.
second despite what the above person says dont touch cams, your going to spend extra money for no reason, cams dont actually make any power, they shift at what rpm the engine makes power(aka torque) and enable greater hp through rpms. greater rpms on a engine means more wear from increased movement and additional heat. a extra 1-2 psi of boost is FAR better then a extra 300-400 rpms. lets not even start on the harmonics and cavitation issues the oil pumps are known to run into with increased rpms on these engines. the whole concept of "but you make the same power on less boost!" is correct, but you dont always want less boost with modern turbos and billet compressor wheels,plus like i said less heat from a little more boost. dosnt matter though because your not going to reach that level without a built engine. as an example i make 850 whp at 32 psi of boost just fine on stock cams, 600 on 20 psi, the only reason the engine is going to get cams is because i am building a custom turbo kit with tuned exhaust manifolds and custom intake with tuned runners and im matching everything to extract every bit of power possible out of my precision 6766. a supra made 1017 whp on one i wanna see how close to that i can get, other wise i would keep stock cams because they provide greater torque down low and are more "fun".
also the above user is incorrect in a turbo kit will cause excessive heat. the heat generated for a given power is the lowest with nitrous followed by turbo, then na, and finally supercharger. why? NA builds power through two things, VE and rpms. the VE on the vq35de is nearly at its practical limits as is, your not going to improve it by more then 1% without some very very expensive parts. so that leave rpms, which require cams to send the torque peak very very far right. When you do this the coefficient of friction remains constant on the bearings, as does the size of the bearings. each rod bearing is about 2.1 inchs by .79 inchs, mains are about 2.4 inchs by .79 inchs. so that gives a surface area of about 5.2 square inchs for the rod and about 6 for the main with some rounding. multiply that by 6 for rods gives 31.2 inchs, and 30 for all 5 main journals, or a total of 61.2 inchs traveled for one rotation of the crank. if you make peak power at 5k rpms this means as far as heat generated from friction the surfaces are traveling about 306,000 inchs compare that to 6500 rpms and you get 397,800. that is a massive change and easy to see why the higher rpm limit sees greater heat imparted to the engine and oil. while a turbo generates heat also ive actually logged temps previously at various parts of my oil system, full 32 psi boost, 30 minutes non stop, 85 degree day, turbo oil inlet temp was 179 degrees, outlet 189, temp by the time it reached the engine was 182 and my main engine oil temp sensor was reading 181 peak before dropping to 170 and holding constant because the oil cooler thermostat opened. so the extra heat going into the oil is negligible. especially since the bearings are seeing about a quart a minute and theirs 9 of them but the turbo only sees about half a quart a minute for both bearings if journal bearing.
^a bit long winded but basically any engine if everything else is the same, displacement, oil type, clearances, same power output ect. the only difference being one makes the power through lower rpm and turbo and the other na requiring higher rpm, the turbo engine will always be the cooler and more reliable engine.(i didnt even touch on harmonics and the weakening effect it has on metals)
also to take into consideration, sg motorsports spent over $20,000 into a 3.5L vq35 and "claimed" 372 whp(he sold the engine and the new owner couldnt even hit 330 without changing anything, on a different dyno and his drag strip times verified it was a low 330 engine) a turbo setup will cost half to 75% of that and make a a definite 420-450 whp reliably depending on the dyno.
finally the suspension, the suspension on the 350z is VERY good as long as parts arnt wore, which the car should be in good operating condition before any modifications. unless you have over 10k to drop on JUST suspension then you dont have enough to worry about that currently. for the average driver you will see 10x more benefit just putting a good set of tires on the car then the best suspension setup money can buy.
not sure why he would suggest meth and NA, but meth dosnt make the engine any safer it actually makes it more dangerous, first most injection systems are primitive so you really dont know how much your injecting, next few systems have any way of notifying the engine computer if theirs a issue with the system and those that do require a aftermarket ecu to actually do anything about it, and third all meth does is increase octane some and decrease iat some, as far as na with a stock block is concerned you will see essentially no benefit as far as iat is concerned, it works just like water with heat differentials, it provides the most benefit when the iat is far hotter then the methanols temp. IE boosted. as far as octane you will get some benefit in increased spark if you use it, however it will be heavily dependant on how much you inject. for the average person it wont even be enough for a single degree of timing. you would need to be injecting about 12% total fuel as 100% methanol to see a major benefit, which injecting 100% has its own safety concerns even i make sure what i inject has some mek in it if im injecting that so it at least burns blue instead of clear if a fire happens. if water is mixed in then you get more benefit in the combustion chamber effectively increasing octane a bit more at the cost of less benefit to iat's however then you are also using up cylinder space with something that is neither air nor fuel effectively reducing the VE of the engine and making less power. while spark timing can be increased the overall effect will be close to null.
your best bet for your money amount is get a good set of wheels and tires, dosnt have to be the most expensive, you dont need volks, tons of track guys run enkei rpf1's, tsw interlaggos, and tsw nurburgrings. a jwt clutch setup with a resurfaced flywheel if you can find a shop do it or a southbend clutch/flywheel combo for a little more, and a boosted performance turn key mid mount that comes with osiris, fuel pump, and fuel injectors. this will set you up for down the road if you decide to build the engine you will only need to change a few parts as his base kit supports 400-600 whp and his numbers are conservative(likely more since precision released the gen two 6266 which now supports 800 hp.)
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jerryd1987
- Posts: 182
- Joined: Sat Aug 06, 2011 9:25 am
- Car: 03 350z many mods inc next year
Re: Advice on turboing my 350z.
just verified with someone who actually lives there, GTM was evicted from their building, are working in a tiny shop now and currently have dozens of customers filing charge backs on 370 turbo kits that where supposed to ship over a year and a half ago and still dont even have a single kit completed. Several 350z guys are doing the same as well do to ordering parts and never received anything after half a year or more of waiting.
so while their phone and website techically still work and they will answer and take your money they are for all intents and purposes out of business and you will likely not see parts if your order stuff from them.
so while their phone and website techically still work and they will answer and take your money they are for all intents and purposes out of business and you will likely not see parts if your order stuff from them.
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AZhitman
- Administrator
- Posts: 54538
- Joined: Mon Apr 29, 2002 2:04 am
- Car: 58 L210, 63 Bluebird RHD, 64 NL320, 65 SPL310, 66 411 RHD, 67 WRL411, 68 510 SR20, 75 280Z RB25, 77 620 SR20, 79 B310, 90 Z32, 91 GTi-R, 92 Silvia Qs, 98 S14, 23 Z.
- Location: Surprise, Arizona
- Contact:
Re: Advice on turboing my 350z.
Great info, Jerry - We need to get you to draft a couple tech articles for the homepage!
Dylan, make sure you read this: 350z-general-information-faq-diy-modifi ... 00526.html
Dylan, make sure you read this: 350z-general-information-faq-diy-modifi ... 00526.html
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jerryd1987
- Posts: 182
- Joined: Sat Aug 06, 2011 9:25 am
- Car: 03 350z many mods inc next year
Re: Advice on turboing my 350z.
let me know what you want, im lesser knowledgeable about brakes/suspension most of my info is in regards to drivetrain but i do know enough to build some fast cars. if pictures are needed might have to wait till october, just had all my equipment packed up and shipped from hawaii to ohio and hopefully ill be ready to open the shop when it gets there.
if the shop is ready at that point it might be perfect as i intend to pull the engine from the z and get restarted on the new turbo,exhaust, intake setup along with a tube front end. received my retirement orders a few months early so had to throw it back togeather
if the shop is ready at that point it might be perfect as i intend to pull the engine from the z and get restarted on the new turbo,exhaust, intake setup along with a tube front end. received my retirement orders a few months early so had to throw it back togeather
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AZhitman
- Administrator
- Posts: 54538
- Joined: Mon Apr 29, 2002 2:04 am
- Car: 58 L210, 63 Bluebird RHD, 64 NL320, 65 SPL310, 66 411 RHD, 67 WRL411, 68 510 SR20, 75 280Z RB25, 77 620 SR20, 79 B310, 90 Z32, 91 GTi-R, 92 Silvia Qs, 98 S14, 23 Z.
- Location: Surprise, Arizona
- Contact:
Re: Advice on turboing my 350z.
Glad to hear - and thanks for your helpfulness! 
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jerryd1987
- Posts: 182
- Joined: Sat Aug 06, 2011 9:25 am
- Car: 03 350z many mods inc next year
Re: Advice on turboing my 350z.
oh yah something i forgot yesterday, just in case i havnt already blown peoples minds lol, something else that NA has going against it is that as velocity increases the amount of force needed to continue accelerating it increases exponentially. Not just due to friction of the bearing surfaces but wind resistance in the crank case as well(this is why on high rpm setups dry sumps actually gain power over wet sumps due to pulling a vacuum on the crankcase) and friction from the rings. so the above would apply to perfect world models which a engine is not. when you start taking these things into account the coefficient of friction actually increases exponentially(i dont have the exact exponent it increases in front of me) so in addition to the friction surfaces traveling a greater distance they are also experiencing a greater coefficient of friction. the above post with assuming same coefficient of friction was just to give a general idea of a single force difference whereas this post is more looking at the whole system
this further widens the gap of heat advantage going to a turbo charged vehicle. although this is a very complex thought process it only takes a basic understanding of the principles at work to understand how massive the difference is. it is the primary reason that alot of high rpm vehicles like pro modified cars running small block v8's turning 8k rpms run small honda bearings, as well as the reason turbo engines are becoming more the norm in every day vehicles.
if anyone at all truly wants to understand the principles at work i can recommend some excellent books including one that is a requirement for first year students at most mechanical engineering programs.
this further widens the gap of heat advantage going to a turbo charged vehicle. although this is a very complex thought process it only takes a basic understanding of the principles at work to understand how massive the difference is. it is the primary reason that alot of high rpm vehicles like pro modified cars running small block v8's turning 8k rpms run small honda bearings, as well as the reason turbo engines are becoming more the norm in every day vehicles.
if anyone at all truly wants to understand the principles at work i can recommend some excellent books including one that is a requirement for first year students at most mechanical engineering programs.
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AZhitman
- Administrator
- Posts: 54538
- Joined: Mon Apr 29, 2002 2:04 am
- Car: 58 L210, 63 Bluebird RHD, 64 NL320, 65 SPL310, 66 411 RHD, 67 WRL411, 68 510 SR20, 75 280Z RB25, 77 620 SR20, 79 B310, 90 Z32, 91 GTi-R, 92 Silvia Qs, 98 S14, 23 Z.
- Location: Surprise, Arizona
- Contact:
Re: Advice on turboing my 350z.
^ One of the reasons I ran a custom-made crank scraper and windage tray on my KA-T.
The good news is it's not hard to make a VQ35 put some real power down - it's just not cheap.
The good news is it's not hard to make a VQ35 put some real power down - it's just not cheap.
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jerryd1987
- Posts: 182
- Joined: Sat Aug 06, 2011 9:25 am
- Car: 03 350z many mods inc next year
Re: Advice on turboing my 350z.
nothing newer is cheaper which is something people seem to fail at grasping. not even the ls engine is cheap to make power on some items are cheaper but then you also need parts that something like the vq dosnt need, like heads. the most common comment i see from 350z pages is "omg why would you spent 10-20k on a 8k car to make 600 whp!" completely clueless thats similar to what you would spend for a ls1 or ls3 with ls3 cars being much more expensive and ls1 corvettes for instance and even ls2 corvettes being no better off as far as a base platform is concerned.
not even a gen 1 small block chevy is cheap to build anymore, you can build it for cheap sure but who wants to spend 6k for 450 whp and the engine is pushing what it can handle without race gas.
not even a gen 1 small block chevy is cheap to build anymore, you can build it for cheap sure but who wants to spend 6k for 450 whp and the engine is pushing what it can handle without race gas.
Re: Advice on turboing my 350z.
Yeah I wasn't planning on injecting or anything, ands it's a 6mt, I'm going to set up the engine for a single or twin turbo, not sure which yet, or the brand. But thanks for the info, definitely going to upgrade the clutch and flywheel.