I was reading in Car Craft last night a comparo between the new Holley EFI RAM and their older Sequential port unit. The article wasn't very interesting until I read the comparo they did between the new EFI RAM and an old Holley TBI quad-pod setup 900cfm unit.

It turns out the TBI pulled within 10hp and 10lbs torque of the EFI RAM. Just goes to show the TBI can be made to build some pretty serious power -- in this case over 400hp -- and compete with some pretty advanced EFI.

adious,
RP.

 

Hey Palric...a little off topic here only because I know Slade will be here shortly and he might have some input. You used 1.17 to calclate flywheel hp and tq. What should I use? I have the auto tranny and you were telling me something like 1.18 or 1.20.
Let me know, thanks.

8redxtsy

 

Just for info , loss along the drivetrain is based of rim weight, driveshaft weight, efficiency of the differential, transmission efficiency, torque converter etc... many many factors to consider...

On average though it has been shown that the auto setups have a 18% average loss through the powertrain.

For the manual setups, it has been shown to be slightly more efficient at a 15% average loss.

The only way to get the true efficiency rating for your powertrain is to do a flywheel dyno and a rear wheel dyno and compare the loss incurred. Other than that, we're stuck with using the consensus average.

As for the TBI article... damn ye... you know I want to build this up.. but am torn b/w a fourth gen and a thirdgen...

If I do end up building this thing, you will be the first to know...

 

Just going by what the dyno guy said. I asked him what the conversion rate should be and he says on average 1.17 x rwhp. SO I went with that but I have heard everything from 1.15 to 1.25 before ???

adious,
RP.

 

Thanks Slade/Palric

I'll go with 1.20, if that's what the dyno shop is saying to do.

Slade - How do you do a flywheel dyno??

 

I hear ya there Vic. For out of the box performance, the 4th gens are hard to beat. They have a better sub-frame than the 3rd gen cars, and the motor has much more potential than any 3rd gen (save TTA). But, they are very difficult to work on, and parts tend to be more expensive overall for 4th gens. It took me 20 minutes to get the carb and intake manifold off my 86 TA yesterday. I'd spend 20 minutes scratching my head trying to figure out how I'd do that on an LT1. If you like to tweak the combo you have (which you strike me as that kind of guy), there isn't alot you can do on a 4th gen, unless you get a laptop and start to edit the PCM.

Each has pros and cons, but I've still got a soft spot for the 3rd gen cars.

 

James, considering you have an aluminum driveshaft with the lace wheels, 20% loss is a bit high in my opinion, you'd be closer with a 17-18% loss... but since odds are we'll never be able to ge the accurate losses each section of the drivetrain produces, your guess is as good as mine.

Kevin, yeah I like messing around with what I've got and the 4th gens never struck me as the do it yourself car... that's why whenever I think fourth gen, get the best one/already modded out there and that's a SS model LS1 Camaro in my book... not to say the TA is any worse off, I just have a camaro preference...

I also did take note of the overall strength of the frame of a 4th gen, which is anytime better than what we have on our thirdgens... I wouldn't mind a fourth gen t-top setup...

 

Slade, your probably right. I didn't take the driveshaft into account. Aswell as the aluminum drums and rims. I'm going to weight my 17's and see if they're lighter than the stock. Besides the car runs strong. If I do the math at 1.17 I get 221hp as opposed to 227hp at 1.20. If the car had a tune-up and the fuel pressure leak fixed I'm sure I would have seen a gain equivelant to yours in the area of 5hp and a smoother curve. Remember (palric listen), with the car on the dyno the ram-air set-up is pretty useless. Obviously with the car racing down the track alot of forced cold air is going to find it's way into the intake hence hp boost. So the home depot project is not a complete bust Palric. If I do the math from that web-site I posted earlier, inorder to run 90.09mph, a 3600pd car requires 205hp at the wheels. In this case it means that my SLP ram air and air foil combined, is bringing me 16hp to the wheels. Easy there, I know, I know. Too much of a gain to the wheels from a ram air system. Though it did advertise a 15-20hp in gain. Anyways, just a few things to put into your head to think about.

P.S. The math at that web-site, in case your wondering about it's accuracy, it was dead on. It told me that if my car travelled the 1/4 mile in 15.551 ET, than at 3600pds 189.2hp was required at the rear wheels. I dynoed 189.7mph.

 

Adsactly as it sounds. Pull the engine, put it on a stand, hook up the exhaust and then bolt the dyno to the flywheel.
Alot of the time this how they dyno engines in mags that you see with like bolt on results, nitrous tuning, rat motors etc.

 

James I dunno.. that would make my car a 180 hp beast...

since 3 tenths, not far off from you in best time...

On top of that I got AC in my car, a stock driveshaft and steel drums.. aluminum drums are expensive and not worth the replacement cost in my opinion.

As well I have a full open differential too... and the worst part... a TBI...

I dunno... what do I believe, the 3 tenths advantage you got on me or a dyno run that states you got 190hp and I got 155 hp... what to believe what to believe...

I do have a question though, what exactly did you pull as your best torque and at what rpm? That would probably explain the whole weirdness going on here.

 

welllllll to the best of my memory I think I pulled 272tq at 3600rpm. The graph dosen't exactly tell you at what rpm you registered your best hp and tq. I got my best tq at roughly the same rpm as my best hp,3600rpm area give or take. This is too wierd. Two cars that weigh roughly the same, one running a tenth faster yet there is a 35hp difference between the two. Don't forget my extra hp from ram air on the track. Something is wrong here definetly. Too wierd. Too many questions and no answers.

 

Your advantage comes to torque curve. My torque curve falls after 2500 rpm, while you still peak around 3000-3200 rpm I believe. Since we're both spending our time at the higher rpms. 3000+ you have a definite advantage over me there. The only prob is your gearing is preventing you from reaching max HP. We should trade rear end lol, that would toss me back into my proper power band and you to your power band and you should find yourself running low 15's at that point.

 

If you think my 3.08's are restricting me from achieving my full potential at the track than how would you like to trade gears? My 3.08's are posi and I have the pre-load springs in my tool box. Bitch to install the pre-load springs but for a driveline specialist shouldn't be more than a halh hour's labour. What are your gears?

 

...don't have gears to trade- but I could use a 7.5" posi unit...

 

To be honest I will more than likely keep my 3.08's. I have a disk rear end sitting in my garage which I'm debating to see if I should upgrade the rear calipers to the 11.86" rotors that came on the 89's and up rears.