V8 Vs turbo V6 is it worth it?

[Okay Z]

Hi everybody,I have been been looking and reading this site for a while now and need to ask a question,about what to do with my z.

I am 17 and have a 1984 300zx 5 speed turbo,and my goal is around 350-400 Horses at the wheels eventually.and was wondering if I should use the turbo v6 or a v8.I have a friend who workes on nissans and he has been helping me and according to him and the people at zcar.com In order to hit 350-400 horses at the wheels with my v6 I'll need to rebuld the engine,port polish heads,upgrade fuel injectors,ecu,put in a racing clutch,upgrade tranny[the stock is weak]upgrade turbo,and put in a intercooler.doing the work ourselves and maybe having my uncle [he is a machinist]do the porting and polishing it will cost around $3000-$4000 which got me thinking Instead of doing all that I could just drop in a mid performance [carbed for easier intalation] small block instead.

 

I have have wanted to do a v8 swap but nobdy seemed t0 have done any into a z31,now it seems a bunch of people have done it and I was wondering is it worth it in terms of cost or would I be better just upping the v6 and turbo? it seems like it would have more room for improvement. .Does anybody have a guide with step by step instructions?becouse I heard that someone [can't rember who ]said they did a basic sbc 350 swap into a z31 for around $2500.The biggest turnoff is that there was so little info on doing a swap.So if there is a guide that lists the engine models used,dimentions of engine mounts ect I would be gratefull for it and I'd have my buddy lok at it and see if he is interested in helping me.

 

On a scale of one to ten how hard would it be?I know the hardest part is figuring it out but if some one did the all that and you just had to follow directions how bad would it be?I live in michigan and about an hour and a half from detroit so getting some detroit muscle would be easy and reletivly cheap[a rebuilt mid performance small block 350 is around $1500 -$2000]especially if my friend and I rebuilt a smallblock from a junkyard ourselves.And my uncle who is a machinist could probly make the engine mounts if I give him a the specs. Also I would like to keep the car a manual tranny prefer a 5 speed but don't know it that is possible,is it?

 

Thanks

[Mikelly]

All this is truly subjected to your abilities to perform the work, have the tools available, and the additional cash it will require.

 

Things to think about are State licensing and inspections, Emissions, and other hurdles.

 

As to if it is worth it or not... That's choice. I've had guys argue with me all day long about the virtues of a turbo over a V8. Can you make 400HP with either platform? Absolutely. Is one better than the other? Depends on the combo, the tune, and the intended use.

 

If you have access to a machine shop, anything is possible. You can do a motor swap on just about any kind of car imaginable... It just depends on the tools/skills/money.

 

That said, There is no kit I'm aware of to install a 350Chevy or V8 Ford into a Nissan 300ZX. There are however a few members who have done it. Run a on V8 300ZX.

 

Mike

[b__sosick]

if the motor in your car is in decent shape then i'd say stay turbo, intercool it, and get the boost under control. it'd be a helluva lot cheaper than the V8 swap.

[Dave88SS]

I have a friend who workes on nissans and he has been helping me and according to him and the people at zcar.com In order to hit 350-400 horses at the wheels with my v6 I'll need to rebuld the engine,port polish heads,upgrade fuel injectors,ecu,put in a racing clutch,upgrade tranny[the stock is weak']upgrade turbo,and put in a intercooler.

 

You need a turbo upgrade, IC, fuel upgrade, ecu upgrade, and a clutch. You don't need to touch the engine mechanicals unless something is already broken. Tranny might be an issue, but upgrading to the FS5R30A (87+ turbo) is very easy.

 

http://www.redz31.com/turbofaq/turbo.faq.htm

[dj paul]

you will be happy either way you go, but IMHO you should go with the turbo.much cheaper and less stress. porting and polishing should not cost 3-4k prob half that. if it is going to cost you that much, you can find performance pistons and do a custom head job with a dremel. (long time). megasquirt 350

bigger turbo 400 (around)

intercooler 200

bigger injectors 300 (i think)

and your tranny should be okay but you would want do do some other little things.

im just shooting this crap off the top of my head so chime in where i was wrong (i know something was =) )

[cyrus]

How about right now you get a boost controller and put your car on a serious diet? You will be amazed what loosing 800 pounds does.

[Okay Z]

Thanks for you input guys.

I did search before posting and The way Alf was talking the swap sounded real easy and reletivly cheap I mean engine around 1500-2000 plus tranny 500 and engine mounts 500.Thats why I was hoping someone would post a guide so I could see if my mechanic friend would be interested in helping me do the swap,I mean If for a little extra effort I could add lot more potential down the road,How much potential does the v6 have?I just don't want to wast my time and money,by taking the easy way out but I don't want to go overboard[well not untill I start making more money]

 

Hey Dj Paul where do you do you'r shopping for parts?according to the people

on zcar .com and the places they list to buy parts here is what the parts cost.This is what I'm told I'll need

Tranny[the stock is weak and won't last past 220 rwhp,and mine has a slow leak]they go for $500,rebuilt or used.I was told to get an 85 na becouse they are nearly industructable and bolt in.

 

As for a clutch everyone recommends the Act stage 3 clutch $350[the stock clutch hardly holds now at around 8 psi boost .Fuel injectors new $300[sometime there are some used ones for 100]I believe that If I sent my stock turbo into pheonix turbo they would charge around $700 to put it into the stock housing and keep the stock one for a core charge.As for intercoolers they run for around $400 on ebay,plus money for piping.

 

This may be a stupid question ,but if I take the heads out to port and polish shouldn't I just have the engine rebuilt? I mean it has around a 198000 miles on shouldn't i just have it rebuilt while it's out and in pieces or can you take the heads out without tearing the engine appart?sorry if it's a stupid question but I'm new to this.[thats why I have a friend who can do this.]Also some recomend putting in a higher performance cam while others don't thinks it's worth the money,what do you guys think?

 

I also need an Ecu around $500 for megaquirt.Thats why I was thinking of a v8 swap Becouse the way Alf was talking it sounded easy and about the same ammount of money.But maybe easy for him is impossible for me.

I got most of the info off redz31.com,zcar.com and the guide at z31.com.

Anymore help would be apreciated.

[Alf]

http://forums.hybridz.org/showthread.php?t=108065

 

check this out if you havn't already, just some pics of my 85 300zx v8.

if you have any questions about the v8 swap go ahead and ask ill try and clear things up for you.

[dj paul]

hey man, sorry i for some reason was thinking you had the stronger year tranny. i have tons of part hookups through friends work and stuff but most of the time they dont have z specific parts. you can get some dsm injectors some people just give them away for next to nothing because they upgrade theirs. alf your car looks great. another thing motor mount will cost nowhere near 500 bucks. im sorry if i offended anyone that payed that for theirs but IMO that is getting rammed in the A**. lol. especially if your uncle is a machinist. ill make you a deal, your uncle makes me a twin turbo manifold (just duplicate the stock flange on the other side of the L series manifold) and ill make you motor mounts. its whatever you want to do. i think you will love either way and to tell you the truth for that kind of hp a v8 would be easier but if i were you i would stay more original because nissan owns.

[Dave88SS]

according to the people

on zcar .com and the places they list to buy parts here is what the parts cost.This is what I'm told I'll need

Tranny[the stock is weak and won't last past 220 rwhp' date=and mine has a slow leak]they go for $500,rebuilt or used.I was told to get an 85 na becouse they are nearly industructable and bolt in.

 

Stop going to zcar.com if that is the sort of info you're getting from them. Everything you need to get your 400ish hp is on jason's (redz31.com) site.

[dj paul]

Stop going to zcar.com if that is the sort of info you're getting from them. Everything you need to get your 400ish hp is on jason's (redz31.com) site.

 

indeed

[Okay Z]

First off I'd like to say thanks to everyone for taking their time to help a noob out.After all the advice the general opinion says that I should stay with the v6,I am leaning towards that way but I don't want to hate myself down the road for taking the easier but not better option.I guess the question is which would be better in terms of speed and cost?I know they both can hit rwh400 but wouldn't the v8 hav more torque?which is more important than horsepower right?

Also would the v6 suffer for being put under that ammount of strain?

The other advantages the sbc has is, it sounds mean,no turbo spoolup,and it's physically bigger so you would have more to work with.

 

My main goal is to have corvette[the older ones not the z06]or muscle car speed and power.I want to show those camaros and mustangs who's boss:mrgreen:

 

It really all depends if my buddy would actually want to do the swap,which I don't know if he would,He offered to help build up the v6 but he likes nissans and their turbo engines.

Alf do you have a writeup or guide I could email him and see if he wants to do it?If he dosn't then I'll have go v6 as I can't do the swap myself.If he'll do it ,I might go for it.Alf you make it sound real easy,is it?I mean besides the engine mounts and tranny mounts how bad is it?especially since you did all the figuring out. Oh How much did it cost you to do?and do you think I could do it for $3000?I plan to do most of the work.[actually have my buddy do the work I'll supervise Lol]Also what made you pick a small block instead of going the turbo way?just wondering.

 

Thanks.

 

Oh speaking of suping up cars I saw this thing on the discovery channel or something like that and they were showing a shop that made peoples cars into racing monsters for them[probly cost as much as a lamborginie to do it]and there were these people that brought in a riced out civic and the mechanics totally redid the engine and modifed everything,in the end it had a racing engine I think v6 and it had like 40psi boost.I mean I can see upping a car if it's cool like a z,covette,camaro ect but a civic?

[Scottie-GNZ]

You are correct that they can both hit 400rwhp and good luck with which ever choice you make. I am responding because I want to clear up what I believe are some misperceptions.

 

I know they both can hit rwh400 but wouldn't the v8 hav more torque?

I would be willing to bet that if both made the same 400rwhp, the turbo V6 will have more torque.

 

The other advantages the sbc has is, it sounds mean,no turbo spoolup,and it's physically bigger so you would have more to work with.

If you want "mean" sound, then the V8 is hard to beat. However sound is subjective. Consider that most ricers with their fart cans think their cars sound "mean". Physical size means nothing more that the engine takes up more room in the engine bay. Having bigger diaplacement means nothing more that the engine has the potential to ingest more into its bigger cylinders. The important thing is how close the engine comes to filling 100% of that displacement. That is why you add bigger carbs or TB/injs, bigger valves, cams that open the valves wider and keep them open longer, exhaust to scavenge the cylinders for a purer intake charge, etc. The more of that you do, the closer you come to 100% efficiency with an N/A but the more you compromise low-speed driveability. Except for exotic race engines, an N/A engine will never see 100% so a 350ci SBC is not really 350ci where it counts. That is how come you see 2-bbl 350s make 180hp and LS1s making 345hp from the same displacement.

 

OTOH, turbos are different and given the amount of boost, will almost always be well over 100% of it physical displacement because the turbo compresses the air going into the engine. If a turbo engine has 100% efficiency, it has the potential to increase its displacement by its original size for every 1-bar (14.7psi) boost. So, the 3.0L engine at 14.7psi has the potential to put 6.0L of intake charge into its cylinders and at 29.4psi, it becomes 9.0L. etc. Again, 100% efficiency is hard to attain with a street car but you get the idea and understand why a 3.0L with a fair amount of boost can have equal or more torque that an N/A almost double the displacement of the turbo V6.

 

Also would the v6 suffer for being put under that ammount of strain?

Yes it will IF you make it detonate. As others said, ignore the "advice" from the zcar.com folks. You do not need to open that engine to make 350-400rwhp. Do a compression AND a leakdown to make sure you have a good engine to begin with then add components that will help limit detonation. Do not think HP, think detonation prevention. Heat is the enemy of any engine but the death knell for a turbo engine so make sure the intake charge temp at the TB is as low as possible by using an efficient turbo that does not generate heat (IOW, do not run the stock turbo to 20psi just because you can), I/C, DP/exhaust and required fuel pressure/volume/octane. The more you can limit detonation, the more boost you can safely run, the more power you will make. It is detonation that stresses the engine.

 

Just because one can get get a "350 SBC" cheap from the junkyard does not mean it will be cheap to get 350-400rwhp out of it. To get that power, the only thing you would end up keeping is the bare block. Everything else goes in the trash or you end up very disappointed. I am a turbo fan but would not hesitate to put an LSx in my hybrid because they are way more efficient than the old-school SBCs and respond well to mods. Given the cost of I/Cs on eBay today and the development of the low-cost Megasquirt, 2 of the important turbo upgrades makes it an easier decision to mod a turbo engine. One advice I would give is tonot buy a turbo unless it matches the needs of your engine and driving habits. Your best bet is to work with someone like 240Z Turbo to configure the right turbo so you do not end up with the wrong turbo and complaints of turbo lag, etc. A 350rwhp turbo V6 DOES NOT have to have turbo lag. Turbo lag is what you make it. Buy a cheap eBay turbo made for a turbo rotary or a big desiel truck and you will suffer the consequences.

 

 

OK, I have rambled enough. Time for a nap

[pparaska]

I can't ADD anything useful that Scottie or others didn't write. (GREAT post Scottie!)

 

I'd personally turbo the V6 for that power level requirement. But like Scottie points out, be careful of parts selection, AND HOW MUCH YOU TURN UP THE BOOST. There are many times people get too overzealous and want a bit more push in the back and turn the boost up too high and waste the engine.

[Alf]

first off here is a very very brief explanation of the swap and most of the required modifications.

 

http://forums.hybridz.org/showthread.php?t=104866

 

if that doesnt give you enough information, let me know and i will detail it or write a new one.

 

to tell you the truth it was a fairly easy swap. i have never done a project like this before and i did it pretty quickly and it went quite smoothly. there is only a small amout of fab. work and it isnt even that hard: motor mounts, tranny mount, crossmember, driveshaft, just to name a few. i completed mine with zero help from anyone,(i did this before i joined Hybridz) i happened to see a z31 with a v8 in it at South Mountain Dragway when i went up for the GM nationals at Carlisle, but i only looked at it for five minutes or so. it will be much easier to do it with pictures of a completed swap. the electrical aspect was simple because i went carbureted.

 

cost wise my project was dirt cheap, the car was given to me, so was the engine and tranny, so i wanted to see how cheap i could build it for, and it came out well below $2000. it all depends on where you get your parts from and how far you want to take it. if you want to build a 400rwhp sbc then figure about 3 to 4 thousand just for that motor. i used a bone stock 305 and a half worn out 3spd stick, they wern't the best parts but they were free. the big expenses come in the specialty parts like: hydraulic throwout bearing and braided lines-$225, custom driveshaft with replaseable U-joints-$210, electric fan -$80, inline rad fill-$25,custom exhaust-$275. and beleive me there are many more nickel and dime parts along the way that add up quick. you may be able to do it for $3000 if you get the engine and trans for less than $1000 which would most likely be a stock unit, and maybe 200rwhp.

 

i went small block because i contain absolutely no knowledge about nissan engines nor have i had any experience with turbocharged gasoline engines. i know sbc's like the back of my hand and i am basically just a chevy guy that had a free japanese sports car thrown in my lap, so what does a chevy guy do? puts a small block in it of course. plus the car had cought on fire a long time ago and i could only get it to run on four cylinders so i just pulled out that melted mess and started from scratch.

 

if i had the expectations you have(350-400rwhp) i would stay turbo v6. the hard part is done, the engine is in the car. and you can mod. it in stages and not have your car sitting in a garage for 4 or 5 months. i don't know anything about the nissan turbo v6's but 3 grand will probly do alot of things with it. plus just think about the fuel mileage, my 355 in my 69 camaro has about 340rwhp and i get around 10mpg, i think a turbo v6 would get much better fuel milleage at the same power level. not to mention my camaro is just plane uncivilized, it would not be a good daily driver.

[Okay Z]

Well I guess the v6 is what i'll go for then.Thanks for all the info and help.If I had more money[not likely anytime soon,unless I pick a winning lotto ticket lol,well the store my brother works at a guy came in and won $75000 so maybe it could happen]I would maybe still consider a v8 as some of you guys on this site have some monsters and I do like the old school style about it, but for what I can afford and do with the car,I guess the best route is upping what I have.

Thanks for helping me figure it out[especially since it is a chevy v8 forum:mrgreen:].I'll be sure to post back when I get it done,and list what I went with.The first step is to replace the tranny and upgrade the clutch so it can handle 8psi,then I figure get an intercooler and rais the boost to 10 or 12.Then when i get more money up the fuel system and turbo,then when and if the engine starts to die rebuild it and then port polish heads ect.

 

Hopefully I can get a job soon and start making some more money to do this[jobs are hard to get in MI escecially if you'r under 18 and in school]and then give those camaros a run for the money:icon6:

 

Oh i'd also like to say thanks Scottie for the info his "ramblings" they some answers and really cleared up a bunch of things.

[silicone boy]

I consider Scottie our Master Yoda of the GN turbo V6. What a motor!

[Pop N Wood]

So if I am reading this thread correctly, you guys just talked some 17 year old into trying to get 350 rear wheel HP out of a 300zx engine with 198 thousand miles on it?

[pparaska]

I didn't notice anywhere that he said it had 198,000 miles on it - I read too fast I suppose. But then again, it may hold up for a while even still!

[silicone boy]

My bad. didn't realize we were talking about the Nissan motor.