Tell me a little about my engine

[pontiacgp]

hey Dr....dyno runs are becoming alot more common than they use to be...I know a few who do it just to give them bragging rights...if the engine is in good shape a dyno run won't hurt it and I assume the op spent a few $$$ for the car. I also assume that one of the major selling points was the engine and unless he wants to tear it down to see what's in there a dyno run would at least satisfy him that the hp and torque are in the range of what was described.

 

[DrRansom442]

hey Dr....dyno runs are becoming alot more common than they use to be...I know a few who do it just to give them bragging rights...if the engine is in good shape a dyno run won't hurt it and I assume the op spent a few $$$ for the car. I also assume that one of the major selling points was the engine and unless he wants to tear it down to see what's in there a dyno run would at least satisfy him that the hp and torque are in the range of what was described.

personally I think a weekend at a track's test n tune would be cheaper and provide more usible info, but you are right dynos are popping up more. A lot of that has to do with the import crowd and yeah most people just brag about the peak numbers .... use the dyno as a means to display their accomplishments .... don't really use the dyno as a learning tool. HP/torque can be estimately pretty accurately by the track results.

 

[pontiacgp]

Dr...we use the dyno for our circle track car...we're limited to what we can modify on the engine since we use a sealed 602 crate and the exhaust is limited to 3 inches with headers but it helps us to set the jets on the 2bb carb. We have to use a 6300 rev limiter chip so it's nice to be able to set up the carb to work at it's optimum performance at the higher revs...

 

[DrRansom442]

Dr...we use the dyno for our circle track car...we're limited to what we can modify on the engine since we use a sealed 602 crate and the exhaust is limited to 3 inches with headers but it helps us to set the jets on the 2bb carb. We have to use a 6300 rev limiter chip so it's nice to be able to set up the carb to work at it's optimum performance at the higher revs...

now see that is using the dyno as a tool .... I think roundy round you can use that info more than the average street car. If he can't do better than a high 14 (estimate) .... he needs an overall picture or why his car isn't accelerating. Something, best learned running down a nice straight track with the timers running .... that is after making sure the car is mechanically sound and in tune. If there is something wrong with the car mechanically ... pretty much the chassis dyno is just going to show you there is really no power getting to the rear wheels and I think we can safely assume that already. Question is why?

 

[pontiacgp]

I can't seem to find the Engle cam or the valve springs he has listed so I'm thinking it may be a typo and the manufacturer is Eagle and I'm no fan of chinese junk so I'd be looking at the cam if there is a drop in the power. With the torque of 500 even with the gears he's running 3:56 he should be able to burn the tires off no problem

 

[olds307 and 403]

Convertor 2500 stall, Performer intake and make sure you have a good dual exhaust with BBO manifolds min. My 403 with single exhaust went totally flat, good exhaust does a lot.

 

[Blake442]

Unless your oiling system has been upgraded, NEVER spin an Olds past 6,000 RPM!

Ask how I know... :lol:

With the power curves on these motors, you don't even need to take it past 5500 anyways...

 

[HurstOlds]

ok

First off, thanks guys for the comments. I was really putting off making a thread like this because I just don't know much about cars and engines. I was really expecting to get lit up for being an idiot and not knowing anything about this car.

I do think this car needs a tune up. The picture linked above is my car. I need to figure out what kind of fuel pump I have on it, I was just thinking about that and I don't even know that.

The car does have ceramic coated headers, but I don't know what kind. It has full exhaust so it could pass emissions (cats and mufflers). I haven't weighed the car yet but it can burn the tires if I want to.

I think it definately needs a tune up. When I run the car hard it's fine. But then I start it up again and it runs a little rough at WOT. Almost like it's not getting enough fuel or something. Do you need an aftermarket fuel pump for an 850 carb? Yes, it's a stupid question, but maybe it's a stock fuel pump or something.

In regards to the dyno runs....I'll eventually have some pulls done. Most of the shops around me charge like $100-$150. I doubt that includes any tuning. The way I look at it, is if I can't beat an old Camaro, why waste the money on a dyno pull?

I'm going to get the car into my mechanic and have him check the timing and all the basics.

I really just wanted a clean rust-free car, so the BBO was a bonus. I really didn't expect much out of it, since it's not really modded much. But after looking around online and around here more, it seems like even stock BBO g bodies are able to hold their own on the street.

I don't know, it's just been eating at me. I figured I would ask you guys. Let me ask this.....do you think my setup would make more or less horsepower than a stock BBO? Mine has stock heads and intake, but all the different internals.

Thanks Joe for explaining the oversquare/undersquare thing. I read somewhere that the 425 was square I thought (stroke=bore) and that's not what you said....so that info must have not been accurate.

I have a lot of learning to do with this car, but the good thing is it runs great and doesn't need much work.

 

[HurstOlds]

That being said, the 10.25 compression and a Quadrajet tells me that it SHOULD run the number depending on the actual cam specs. Since you did not list them, it is difficult to say for sure.

In regards to the cam, the sheet I have just says:
Engle Cam 107* JM20-22H

I don't know jack about cams, but looking over Engle's website, under their old catalog they have something that's similar. The grind number is: ep-20/22hyd

The specs on that cam are 1800-5800 rpm,
IN: .496 268 .310 226 110* (degrees)
EX: .512 274 .320 230

But my spec sheet says 107 degrees. So I don't know if that's a custom grind or what. The idle is a little lopey

The numbers above might be a little off. It's hard to read Engle's crappy pdf file picture of their old catalog. Here's from Engle's online 'old' catalog:

Here's some specs that are supposedly from Modello's site for a cam that's basically the same or similar?
0.496 0.512 266°/274° 226° 230° 110° 1400-5800

 

[HurstOlds]

However a BIG variable as to why you got "walked on" by those cars is rear end gearing. I'm geussing you have a g-body, in which case you could have anything from 2.14's(not a typo 2.14) all the way up to 3.73's.

My car has a Ford 9 inch rear end, with ~3.56 gears from what I was told.

I did better against the Camaro from a roll, I think it was about even or with him just barely pulling on me.