Best synthetic for High Rpm v-8 Corvette ??

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5abi6r

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Hi everyone, been a long time since i've been here... I have a 93 LT4 corvette. We've almost finished assembling a very lightweight very high rpm motor (fully forged/lightweight everything.. and i mean everything !) Its a solid roller with a high volume oil pump and we should be making peak hp at around 7000 rpm and we're looking to shift it at around 7800-8k rpm. It is a 388 stroker (6.3 or so). It's not huge cammed but we're still expecting 425 + rwhp out of it.

I used to have a bike and since i never cared about them i used to cruise around at 10-14000 rpm all the time because i loved the noise
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(04 gsxr 60 and then 05 gsxr 750- 13,500 rpm in that). I plan on cruising in my vete at higher rpms all the time and will be driving/racing it fairly hard.

What would be the best oil that you guys reccomend? Its only driven in warm weather and usually at nights. It will see 1/4 mile duty until i get booted because i have no cage but maybe the occasional auto-x too or mosport track day. We've spared no expense in the build and i'd like to learn about what might be the best oil suited for my app. the shoppe plans on using dino oil for the 20 min break in.. and then reccomends mobil 1. I do know that hes fairly set on mobil 1 but hes a believer when he can see hard facts in front of him. I do believe hes really clueless as to what viscosity we really should be using.

Recommendations for oil? viscosity? Im in Toronto area Canada.. so temperature is always around 10-15 degrees (nights) and up to 40 during days ( i never like driving it hard in heat anyways). sorry for the long essay if theres any info you need on the motor i'd be happy to discuss it!

Any help/input is appreciated !
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Is this a Gen II engine? What are the clearances on the mains and rods? Which high volume oil pump? Any modifications to the oil passages in the block? Make sure you install some accurate oil temp and pressure gauges.
 
I can double check with them about clearances on the mains/rods. I believe the pump is a melling? i will double check as well. i have a canton 7qt oil pan and i honestly don't know if there were any mods to the oil passageways. I'll post what i can asap about that.

As for the guages.. are the oem guages that off or do you think they're just not reliable. i used to have a pod but i sold it thinking it was too 'tacky' looking in the interior. I think i may have to grab another..

appreciate the response ! Im guessing you have the new z? . dam you .. spoiled my party
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9was 02 when i started this rebuild.. havn't driven the car since. now its done and theres a 450rwhp moster straight from gm !!)
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German Castrol 0w-30.
Will your computer support that rpm and who is burning the chip? I know the MAF stuff the 94-7 the pcm is hardare limited to about 7200rpms.
Sounds like you bought a set of LT4 heads for it, did you have them worked over and by whom?

I am reassembling my stock shortblock LT1 today with ported LT1 aluminums and a custom hydraulic roller, aiming for 380-400rwhp through an auto and only reving to about 6300 or so. My car is a whole lot bigger(over 2 tons) though so I am only shooting for low 12s.

I would lose faith in a shop wanting to "breakin" a roller cam in doing so you will lose the chance to really seat the rings. With a roller cam start it check for leaks and levels maybe change the oil then go put some load on it to seat the rings before the bore glazes.

On M1 I would go with 0w-40, the "usual" weights in M1 have historically been too thin for the LT1 but word is they are improving.
 
I would say for your application the Series 2000 TSO 0W30 or the ASL 5W30.
We have been using both in the Reher Morrison 555 ci 950hp engine in the 68 Firebird I sponsor.
my prices to CDN board members is pretty good.
You can even pick it up at the warehouse in Mississauga.
 
If it were my car I would use:

1. Redline 5w-30 or 5w-40

1. GC 0w-30

3. Synergyn 3w-30

4. Mobil 1 5-40

5. Amsoil AFL(old formula) 5w-40
 
I guess I will have to watch out for you on the streets, my 98 Corvette doesn't stand a chance with it's measly 299rwhp.
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I think for this engine that Amsoil 5w40 would be an excellent choice. Anything thinner than this would just be taking too much of a chance with that strong motor, I don't think the lighter oils can handle it.

The only 30 weight oil which I would even consider for this engine would be German Castrol Syntec 0w30 (which you can find at any Walmart or Canadian Tire up here) That's what I'm running in my Corvette. But if I was making the kind of power you were making I'd probably step up to something a little thicker (after seeing my oil analysis results first though) This brings me to another subject, with an engine like that you would be wise to get an oil analysis done on whatever oil you end up choosing. I use Wearcheck in Mississauga for my oil analysis.
 
Thanks for the responses everyone! As for motor details it was built using a donor lt4 motor from a 96 corvette so it sort of is an LT4 to begin with. We wanted to begin with the oem castings for trueness in ports etc. The stock ecm is good for 7200 rpm and maybe just that. we've completely removed it. We are using a gen 7 dfi with a distributor in the back of the manifold (dual sync) to give us much more tuning capability and the rpms we're looking for. The power #s were on the conservative side of course, i dont want to be dissapointed but for 1/4 we're expecting around 124 + mph easily on street tires ( 19" Pirellis)

As for oil, I have to admit i am sort of swayed by using a performance oil, ie. Amsoil. Most people are reccomending a 0 or even 5 weight oil is this because thinner oil is needed for higher rpms? Some have said 5w 40 but Don whom i believe is an amsoil rep has said to use s2000 and weights in 0w30 to 5w30.

Now from what i am reading every oil is different even though it can be rated the same viscosity, but ill admit the more i read the more im confused about what actual vuscosity might be best
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On a personal note I have always used mobil one but from what i think i am learning is that it is really not formulated for high performance motors and maybe i can do without all the extra detergents and go for an oil that can be better for my app and change it more often.

appreciate the input thanks !
cheers.gif
 
forgot to mention im not familiar with oil sampling or whatever is done with that but would really want to take a part in that. Whats the actual process? what do i do? The motor is assembled just waiting on intake parts and all new sensors and a new rear end.

This is going to be an interesting break-in period for me when its together because not only the motor is new.. the mecloud street twin clutch is new (alum flywheel), the brand new zf-6 that was rebuilt and strengthened by Bill at zfdoc is new and so is the rear end. I've pretty much got an all new drivetrain front to back as we've also replaced the driveshaft with a ss steel one, all new stegthened u joints and ss halfshafts too. I have new brake pads and rotors too (list never ends !) but im going to wait on that until everything is worked out with the motor and tuning.
 
Given your rollerized valvetrain, the reality is that any quality oil of SAE 30 viscosity and decent HTHS that is shear stable will provide all the protection you need. The clearances (which are determined from other factors) will then determine whether you need to increase/decrease the viscosity from this starting point. Synthetics (including group III) provide additional high temperature insurance for a variety of synergistic reasons. A good engine builder should ASK YOU what viscosity oil you would like to use and then build the engine for it. OR, if you haven't a clue, he should build the engine and then TELL YOU what viscosity oil to use. In any event, accurate oil temp and pressure gauges (along with professional UOAs) will allow you to optimize your choice given the peculiarities of your engine and the environment you operate in.

How high of quality oil do you need? Well I've seen numerous Corvettes tracked all season long on nothing more than M1 10w30. The key is they keep their oil temps in check with a good oil cooler.
 
With that set up I would think a thicker 30wt with a STOUT film strength would be the best bet. GC just naturally comes to mind in that regard. I would personally hate to run an oil that is too thick and rob you of power for no return. M1 0w-30 Racing oil would have fit the bill nicely if it were still readily available.
 
quote:
Originally posted by ncirish:
With that set up I would think a thicker 30wt with a STOUT film strength would be the best bet.
Click to expand...
What value of film strength do you think is the minimum required here?
 
LT4 was not available until 1996 and only 1996, so I assume (like DJ) that you have the LT4 head kit from GM performance parts. Nice kit - I have a 94 LT1 with the Lt4 heads and not as many mods as you are doing - wish I could have a 383! In any event, I'd stick with the Mobil 1 since its been good to me so far and with good UOA's. My dad thinks Redline would be better for you setup.

Bottom line - do a UOA as Patman said and go from there - you may vbe able to save money. But remember that the corvettes came from the factory with Mobil 1 syn oil. This is because they were able to eliminate the oil cooler (less weight abd complexity)since syn oils could stand up to heat better. So, I'd choose some sort of syn oil unless you added a cooler - which would be a good idea with that 383 setup.
 
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