820 RWHP and climbing.....

[BLOWNGTS]

Another question. With just the Paxton supercharger and a few minor add-ons I am making 820 RWHP at 5,000 rpm's (dyno) . I am in the process of putting a fuel system in. My question is how much HP will this Viper engine handle. I am not sure where the RWHP numbers will stop after it gets the fuel it wants beyond 5,000 rpm's. However I do not want to blow the bottom end out either . Anybody know what the max HP this stock engine can handle? Thanks, Matt

 

[FranciscoR.]

Do you mean the engine with mods and stuff or just the block?

 

[Anthony - 98 GTS]

Great numbers!!

You are starting to push the upper limits of rwhp on the stock bottom end. Most people putting that power to the ground have at least changed the pistons or done something to lower compression on a boosted application.

I think there are a few boosted cars with more power on the stock bottom end and there are several N20 cars with higher numbers.

How much boost are you making?

 

[BLOWNGTS]

Mostly the block. However if you see any problems that might arise in the motor that too.

 

[BLOWNGTS]

12 psi right now. Thinking 13 or 13.5 when we hit 6500 rpm's. Getting some blow by now out of the dipstick.

 

[Anthony - 98 GTS]

Mostly the block. However if you see any problems that might arise in the motor that too.

The block is strong - I know a [******] TT has put down 1093 rwhp. So you have room to go.

 

[FranciscoR.]

I always figured that a Viper block could handle 1000+RWHP. They have special modded Vipers that run over 1000hp. But this is obviously with tons of mods. I would listen to Anthony on this one mostly. I would imagine at this point you should seriously start thinking about limiting HP and being careful man. 800+ is amazing as is. I would say up to the 1000hp mark, its the mods that limit the hp, not the block. Above hp, the mods take second seat to the strength of the block itself.

 

[Dr Roof]

My car put down 848 rwhp and 882 Ft lbs torque on stock bottom end! you have room to go just be careful!

I think it is all in the tuning!

 

[Russ M]

[******] claims his twin turbo plus nitrous car that has run 8's and made about 1100rwhp is on a stock bottom end. And I tend to believe him, 110hp per cylinder is no big deal long as the a/f mixture is good and timing is safe.

I would think your first weak link will be the head gaskets.

Fill us in on your mods please, sounds like lots of power for just a paxton blower at 12-13 psi.

 

[BLOWNGTS]

Have a Paxton on my '96 GTS. Have several small uprgrades added on the system (bigger injectors(50), fuel rails, smaller pulley(275) 4R tuning and cat back corsa exhaust. That is it. Nothing major. Really did not expect to be climbing into the 800+ RWHP territory. Might just put it back to stock Paxton kit and be happy with 600 RWHP. That will be enough to bust most asses and I won't have to worry about the bottom end and changing the fuel system. Will keep you posted.

 

[dansauto]

? 820 RWHP and you have not upgraded your fuel pump, yet have bigger injectors?

 

[BLOWNGTS]

Dude, I did not expect to hit 800+ RWHP. Thought I would be looking around 700 RWHP and was hoping the stock pump would do the trick. Understand now?

 

[dansauto]

yes, weren't they monitoring the air/fuel ratio while on the dyno?

 

[not stock]

Getting some blow by now out of the dipstick.

If this is the case you have blown your pistons.

 

[BLOWNGTS]

Of course they were. It is at 12.4 or so at 5000 rpm's. Why we know we have to have fuel pump. I was just trying to get by w/o one b/c I want my car back. I see the error of my ways now and will probably just be happy with 600 RWHP for now. Matt

 

[dansauto]

heck the fuel pump upgrade on a GTS isn't too hard. Your car is obviuosuly capable of the power, just set up a return style fuel system. You'll never be happy with just 600 rwhp.

 

[utahviper]

I think the cars that made that kind of power did not have the stock bottom end. From my understanding they were stroker 510's with different pistons and rods. My guess is that they also bored it out a little but I do not know for sure. So when the crank and rods are replaced or modified I don't consider it a stock bottom end.

 

[BLOWNGTS]

Getting some blow by now out of the dipstick.

If this is the case you have blown your pistons.

I know what you are saying but I don't think that is the case here. Done leak down test and no problems found. I do have the MGW dipstick top and it sits a lot looser than the tight factory one. Almost positive that is where the blow by is coming from.

 

[BLOWNGTS]

Thought about doing the return line but if got all the stuff basically apart to do that then I would just do the whole fuel system. Now I am starting to reconsider the 600 RWHP now. I like the idea of having 800+ RWHP I just don't want this motor giving up on me after all the work. Matt

 

[Vipermed 97.01]

820rwhp and your not running out of fuel on the stock system.Wow send that magic bullit our way.We seem to run out of fuel at about 635-660.I will tell you this if you are going keep this kind of HP.The biggest problem your bottom end is going to have is when you start running out of fuel and running lean.Trust me it will happen.You need to upgrade that whole fuel system and run a return line.

 

[Torquemonster]

Do the fuel as everyone is saying - it'll be worth it.

The block is stronger than anything Chrysler has put into a production car before. Even the old Hemi cast iron blocks won't take the power the Viper block will. The crank will break before the block cracks assuming no detonation.

Stock crank ratings vary - Venom TT cars have apparently been tested to over 1000rwhp on stock crank, while others say 900rwhp is upper limit... if it were my car - I'd opt for the lower figure as a reliable ceiling.

Testing to 6500rpm at 13.5lb on stock bottom end?

.....Pop!! I wouldn't do that if I were you. YOu have a rod ratio around 1.6:1 - that isn't real good for high rpms.

If you want to run 850rwhp and 6500rpm - you need a stronger race prepped crank, lighter and stronger rod/piston combo, and the ring lands suited for a blower application. YOu need accurate and stable engine management and A/F in the mid 11's at WOT.

What you have right now is a hand grenade - I'd detune or upgrade to make it live.

 

[Dr Roof]

Utahviper

Trust me my car was dynoed with the stock bottom end, No upgrades at all. 100% stock bottom end.

Somebody get blownGTS some fuel! If he gets some fuel he will be over 1000RWHP!

 

[Joseph Dell]

I'm not sure if this is the case, but I'm going to guess that the Paxton kit is using an FMU for fuel delivery? Actually, it couldn't be b/c the FMU relies on blocking the return line... hum.

So how does the fuel on that kit get into the engine?

JD

 

[Mike Brunton]

So how does the fuel on that kit get into the engine?

JD

I *think* it's through the injectors

 

[BLOWNGTS]

For those of you that have not read the entire post I know I need a fuel system. We have not run the engine past 4800 rpms and have shut it down every time before it goes lean. I did not expect to make this much HP at such low rpms. I have been just getting input before I decide to go with the fuel system or just take the 600RWHP the stock Paxton kit will give me and ride. Thanks for all the help and input guys. I will keep you posted. BlownGTS

 

[Dr Roof]

Can you p[ost your Dyno sheet! I mean you have some big power for no fuel. I would like to see how soon it comes in. Most people making that kind of HP will not get there until peak RPM. You are making 820 before 4800 RPM that is almost unbelivable with no fuel. Please sho us the Dyno Sheet!

 

[Paxton-Rep]

The fuel system that we provide for the viper consist of Two fuel pumps and a FMU. We have found a way to incoporate a FMU into "returnless" fuel system, but it will only work with the way we have it set up. For details go to www.paxtonauto.com and in the downloads section you can see the schematic for the fuel system. By no means am I saying that Paxton's fuel system will support 820hp, but it has been tested safely to 620 HP, when the kit comes from us we set the tune safe!

 

[BLOWNGTS]

I AM HAVING THE SHOP EMAIL IT TO ME SO HOPEFULLY IT WILL BE ON TODAY. IT MAY ONLY BE 780 RWHP AT 4800 RPMS, BUT STILL IMPRESSIVE BEFORE IT GOES LEAN.

MATT

 

[BLOWNGTS]

Re: 780 RWHP and climbing.....

KELLY DID YOU GET MY EMAIL? I NEED SOME HELP GETTING THIS NEW FUEL SYSTEM SET UP AND IN. PLEASE CALL KEVIN WHEN YOU GET A CHANCE. MATT

 

[utahviper]

Re: 780 RWHP and climbing.....

Dr Roof,

I was talking about the RussM reference to the Twin Turbos in the post above. I don't think they made 900+RWHP with a stock bottom end. I have no doubt you did but the turbos I don't think did.