XXO/BVGC '38 Chevy Coupe Build

[Sumner]

Sum, Your math matches mine! I figure we'll be spinning 6087 RPM at 185 with no tire spin. We've spun over 6200 in Ohio, so we'll go with that at El Mirage. I think with the short run, we'll need to keep this thing running hard.

We may drop down from 2.54 on the salt, to 2.40. In the past, I've been over optimistic on how tall a gear the car would pull-I don't want to make that mistake again.

If you can run to 6000 then keep the 2.54's on the salt as 6000 is 203+.  My question is did you run it to 6000 on the dyno.  If so what was the HP there?  If not make sure you aren't dropping after the 5500.  I'd gear myself for the the peak HP.  Just shy of it by a 100 rpm or so.  Just me,

Sum

[SPARKY]

Buddy,, Go read "One Hot Chilli Pepper" Frt. Eng. Dragster  they have some mighty interesting stuff about pop and how much you have to run to beat 100% alky.

[38flattie]

We never ran past 5500 on the dyno, although we did run 6200 at the onio Mile.

I think I'll stay with the gearing for El Mirage, and see how it does.

For the salt, I think maybe we'll try and step out to the 4 mile, with either the 2.35's or 2.40's.

Sparky, I'll look it up and read it!

[Sumner]

...For the salt, I think maybe we'll try and step out to the 4 mile, with either the 2.35's or 2.40's...

I'd go with the 2.41's.  Just a hair over 5500 is your 200 with those.  You know you can pull the 5500 and what the HP is there.  You don't know what it is over 5500 even though you ran higher rpm's. 

Where was the cam suppose to work? 

Also what kind of 2.35 gears do you have?  Are we talking quick change ratios?  I was talking GM 2.41's,

Sum

[Jack Gifford]

re: the dyno data. Besides Rex's question about timing; I'm surprised to see leaner A/F numbers with the 10% nitro. But I've never been there/done that- so have no feel for it. Was there any optimization of A/F with nitro?

[lsrjunkie]

Awesome Buddy! Good to hear things are going well, and good to see you back around these parts. That old Flat Cad is a beast! Here's to getting that magic number this year! 

[Frankie7799]

Very cool Buddy. Looking foward to seeing how everything pans out at EM and the salt

[Rex Schimmer]

I have to agree with Jack regarding the A/F ratio, is the additional hp from the 10% pop or from being leaner?? Also are the oil temps correct? 74 deg F looks really low if you ask me. What oil were you running?

Looking at the dyno sheets it would certainly look like 5500 rpm is not your max hp rpm as each rpm increase saw a nice step up in hp, so going to 6000 might be what is needed to make the big 2!

Rex

[38flattie]

Thanks Guys!

Yes, we have a oil heater on the car, but not on the dyno, so oil temp was not always optimal.

Nitro does lean things out. As we had limited time on the dyno, I was looking for 'safe, fat' tunes. When we get to the salt, we'll run the safe fat tune, and see how much it leans out at the 3 and 4 mile.

Now, I must confess- Sparky was right, and there is a little more to the story.

We tuned on the nitro a bit, and had a really, really strong run going- look at the numbers, before the head gasket between the 6 and 8 cyls started leaking!

This tune scares me, though, and it is truly my 'pocket card'- I'll only consider running it if we are a few MPH short of our goal.

As for how the car pulls to 6000, that is one of the reasons I have picked the gearing I have for El Mirage. We are running on a 185 minimum, and I really don't think we can get there. I really just want to shake down the car, see how it performs, and get the engine teched and sealed.

[jimmy six]

After reading your chart I would be looking at a peak of 4800. I set my first record at Bonneville in 1975 with a carburated GMC on gas at 144 mph turning the engine 4700in a stock bodied 40 Chevrolet coupe....took me years to better it. I continue to gear for the max up to best HP. Good Luck.....JD

[SPARKY]

put the 2.54s in it  and go for it at both places  you are going to have LEAN on Miss Piggy and make her SQUEAL  do what it takes to get the gaskets to hold o-rings ect--- she can do it  just put the whip tow her and make her like it!!!!!

[Finallygotit]

Sparky??    Are you into kinky stuff?   

[WOODY@DDLLC]

Buddy, looks like 4700 is the HP peak to me on this chart! Is that a normal torque drop for a blower motor with fugly ports? It seems to try and recover at 5200. Or is that where the head gasket leaked? I projected the torque curve just to see where the HP might end up! 

[38flattie]

Woody, 4700 is peak HP, because that is where the head gasket gave out. We were making great power on this run, and had it continued to 5500, like all of the other runs, it would have been impressive!

[Roseville Carl]

Just keep on sneaking up on er Buddy................you are kinda like a carpenter driving a 6 penny finish nail with a 10 lb sledgehammer