turbo vs non turbo?

[TWOJZ]

how is the compression lower in the turbo VS non turbo? is it different pistons, head, head gasket, crankshaft, stroke?

are the internals the same, except for the compression? does the non turbo have the same internals, pistons, conrods, and crankshaft as the turbo? will they handle the same boost if the compression is lowered?

I'm considering supercharging my VL, but I plan on lowering the compression first, so its similar to the turbo RB30, but only if the internals are just as strong...

[VN_Luke]

I think turbo is 9:1 and non turbo is like 7.8:1

The difference in comp is in the pistons only. (same rods, crank, bearings etc) Both run a crank girdle setup.

The turbo oil pump is also different to the n/a one - however people seem to be running n/a oil pumps on turboed motors with no issues.

It's not uncommon to hear of stock high-comp bottom ends pulling some impressive figures. - the bigger hp cars seem to use a MLS gasket as the stock one apparently has issues holding big boost, but I'll see if I can disprove this on my car.

With an intercooler, good fuel and a good tune, 9:1 comp shouldn't hold you back from pulling good numbers... In my opinion the comp was kept that low in the turbo motor due to a lack of an intercooler, and a car that was going to be run on crap fuel by the masses... hence introducing a pretty big safety margin as to save motors grenading themselves on a 45 degree day on a bad batch of low-octane fuel towing a 2 tonne caravan up a hill... you'll find that the intercooled rb25det's are running a 9:1 comp ratio.. (i'm pretty sure)...

Check out this thread for more info re: high comp fun!
HIGH COMP who is the fastest? - calaisturbo.com.au

I intend on seeing just how much power I can get out of my dead stock high-comp rb30 before I put a purpose-built one in. (note that the comp. on the purpose built one is in the vicinity of 8.5:1) I think any lower than that and you start getting a very 'doughy' car off boost, which is fine if you're drag racing, launching off the transbrake and staying on big boost for 400m , but not so much fun for a street driven car..

And remember - the stock bottom end is worth all of 100 bux and a day's work - so even if you do manage to blow one up (which should be very hard if you have a good tune..), you can replace the bottom end and do the thicker head gasket while you're at it - with minimal extra effort

Good luck!

[TWOJZ]

looking to super charge my daily driven vl, nothing crazy. What boost could be safely run from an sc14 on a stock engine. What other mods? What injectors, what to control it all? Thanks.

[rb26dett]

My VLT runs fine off boost, but with the turbo I have it is quite laggy when coming onto boost. If I went to a BB turbo, then that would help the problem somewhat.

[VN_Luke]

On the 3.8 v6, without changing the pulley setup dramatically on the 'snout' of the charger, the most you can get out of the charger (pulley wise) is about 10psi-ish.

On a 3.0L motor that might jump up to about 13psi-ish? - you just have to factor in the ratio of motor:blower to make sure you're not going to overspin it too much - I've found 'instantaneous' bursts of around 15,000rpm do no harm.

heaps of people run 10psi on high comp converted RB30E's with no gasket-blowing issues. (of course you need the extra fuel for this!!). I think this is also around the limit of the stock VLT injectors.

to keep things simple and safe, you could probably go with a set of VLT injectors, a VLT ecu, and machine down a pulley for the sc14 to spin her up enough to make about 10psi..

this should, in theory, give you a pretty well running car with a fair bit of poke. - of course you'll always gain more from there with a tune.

Instead of getting a 'vlt' ecu, you could spend an extra little bit of cash and get "nistune" (NIStune - Nissan Realtime ECU tuning) which will allow you to remap your stock ECU to VLT ecu spec, and then tune further from there!

have a read about some of the sc14 threads on the v6's - might be an idea to move the throttle body in front of the supercharger as well...

so your setup would look like

Air filter -> MAF -> throttle body -> charger -> intercooler -> motor.

interesting idea, anyway! keep us updated.

My VLT runs fine off boost, but with the turbo I have it is quite laggy when coming onto boost. If I went to a BB turbo, then that would help the problem somewhat.

yeah they'll definately run 'fine' (unless there's silly low comp!) - but you could be getting more 'poke' down low out of a higher comp bottom end, and probably be spooling your turbo a bit earlier! - in either case a BB unit will be kickass

[VL_5SPEED]

Im going to be running high comp. Intercooled, Stock vlt ecu, stock vlt injectors, stock turbo dump, stock dump to cat with a 3" exhaust. Will be getting it dyno tuned straight after its turbo and running around 8 or 9psi.... Should be interesting too see how much power it pulls.

[TWOJZ]

what kinda power could i expect from an RB30 with 10psi of boost, a full 2.5 inch exhaust. And good air intake.. And what power will the auto trans take? Haha. :P

[Dose Pipe]

Air filter -> MAF -> throttle body -> charger -> intercooler -> motor.

doesnt have to be that way tho can also be

Air filter -> charger -> intercooler >(waste gate in piping) -> afm -> throttle body -> motor.

by putting a wastegate in there with a spring about 1psi higher then the max boost the charger produces this will open when the throttle body is closed, and the supercharger will also run alot cooler

[pumba]

what kinda power could i expect from an RB30 with 10psi of boost, a full 2.5 inch exhaust. And good air intake.. And what power will the auto trans take? Haha. :P

a mate of mine has just done the same conversion u are thinking of doing. he had a VL 5Spd RB30 (N/A) and he put on a SC14 supercharger. non intercooled, standard injectors, standard ECU. pretty much bolted on the blower and went. apparently it did go prety hard afterwards, but he sold it not long afterwards, so he didnt get any power figures or 1/4 mile times. obviously with a tune, injectors and cooler, it would have gone a hell of alot harder, but he didnt do any of that stuff, and the motor probably wont last to long either.

[rb26dett]

what kinda power could i expect from an RB30 with 10psi of boost, a full 2.5 inch exhaust. And good air intake.. And what power will the auto trans take? Haha. :P

Probably on par with a stock VLT. For the Auto I would recommend a good trans cooler which should help the auto last longer.