Can I get 20 more Horsepower?

[ward00]

I just finished a weekend road trip in my recently purchased an 1800 75 Spider. It performed like a champ, but it made me hungry for some more horsepower. I'm wondering how much more HP I could get out of it with out going to the 2000 engine.

-How many extra HP do you think I could get if the cams were timed/tuned to take advantage of my Vicks street cams? (the adjustable cam gears have not been adjusted).
-How many extra HP do you think race cams would provide?
-How many HP do you think a lightened flywheel would provide?
-Any ideas as to other HP improvements could be made without changing pistons, differentials, or super duper porting/polishing.

I,m making the assumption the car as presently configured is capable of 120HP

Here's what performance improvements the car currently has

10:1 pistons, main and rod bearings (engine is a 1800 with stock bore and 10 under bearings)
Dual IDF 40 weber carbs
Custom air cleaner
New adjustable timing gears and 1” timing belt
Vicks street performance cams
Over size intake and exhaust valves
Stainless headers and stainless exhaust system
MSD electronic ignition (I have 10 degrees of distributor advance)
All smog removed

[Odoyle]

The 1800 can be a fantastic power unit, when they went to a 2L in 79, everything got bigger, flywheel, crank, etc...not to say that was the wrong thing to do, but 1800 is great motor. One thing to keep in mind, is that there is almost nothing worse for the motor than an out-of-balance assembly. The crank pulley and flywheel are both balanced specifically to the crank when the motor was originally built. Throwing on an lightened flywheel, or aluminum crank pulley could very well destroy main bearings within 1000 miles, if it has not been balanced with the crank. Other might challenge that, of which I would like to hear from. Even putting the flywheel on in the opposite direction it was removed can prematurely wear bearings. None of this is to discourage, just some things to keep in mind.

[Yadkin]

With the parts that you've already got on there, why not take it to a local tuner to tweak what you have?

[ward00]

I'm sure a tuner can dial in the cams better since they are both at zero. One of my questions was directed to how much HP did you guys think doing could possibly add?

Also, I'll take under advisement that lightening the flywheel needs to be done correctly, but again how much HP gain can I get from doing so?

Since, I already have most of the harder to implement stuff in/on the engine, if the gain from the improvements is only going to be minimal, I would rather change over to a 2 liter and start trying to do Croft type mods on it.

[joelittel]

With the mods you’ve listed you very well may have already gotten 20 more hp...

Get it on a mustang dyno and see where you’re starting at.

[ward00]

Yes, i KNOW that over stock I now have 20 more HP. I'm trying to figure out if I can get another 20 HP without increasing compression over 10:1.

My questions are repeated again:

Can a lightened flywheel and street cams that are dialed in (as to no dialing in) get me the 20 HP

Additionally what type of increase in HP do race cams give over street cams?

[baltobernie]

In order to answer your question, I'd like to know what your present setup is producing. If you've already dyno'd your car, please post the graph. My engine is similar to yours, and it looks like this:



If you're not seeing 100+ WHP, your engine is not dialed-in. Get it to these numbers, at a minimum, then maybe you won't need "another 20 hp".

The first step in maximizing what you've got is to measure and ensure all systems are within spec. Cam timing, valve adjustment, static ignition timing, ignition advance, fuel delivery and float level, carburetor balance, compression variance between cylinders, A/F ratio throughout the RPM range, etc. Then you can begin tuning: changing ignition advance curve, optimizing fuel delivery (Webers are almost infinitely adjustable) ... each time verifying with another dyno pull or stopwatch or spark plug examination. Departing from the stock setup is often counter-productive, rarely inexpensive, and often frustrating.

A lightened flywheel will not increase horsepower. Higher performance cams will make a little more power at higher RPMs, but make less than you have now in the lower revs. The more aggressive the cams, the less tractable the car is on the street.

[ward00]

No I have not dialed it "in". The car was running so nice when I purchased it, I did not want to poke the bear before my first road trip. Now that the trip is in and my HP appetite has been wetted I'm ready to start tinkering. My baseline as of right now is just that, a nice running car. Your post kinda answered my question - that the carbs alone might have more HP in them. A dyno run is on the horizon and when I get it done, I'll return to this thread.

In the meantime, I'm still trying to get a ball park figure as to what type of HP increase could race cams provide (over street cams), and separately, what kind of increase in HP could a lightened flywheel provide?

[AndyVAS]

Since machine work has been done to the motor, dialing in the cam timing could help greatly or none at all. At the worst I have seen cam timing off by 7 degrees. Correcting that can make a noticeable difference. I have also seen cam timing at was only 1 degree off on just one of the 2 cams. You won't know until you check. My best guess is you would only see 5hp change by taking the worst I have seen and correcting it.

The flywheel is absorbing a fair amount of power. If you get a lightened unit you will feel the difference. Should free up 5-10hp depending on how much weight is removed and where in the power band you are. It isn't really making more power just isn't eating it up by spinning up a heavy flywheel.

[ward00]

The guy I purchased the car from said he did not advance or retard the cams, just left them at TDC. Any suggestions what a starting point would be to set them at. They are Vicks street cams. I won't adjust them until I get a dyno done, but am curious where you would start. Thanks

[baltobernie]

Every aftermarket camshaft ships with a specification card. It describes the lift and duration specifications of the cam. For the cam(s) to operate at the designer's goal, the installer must ensure that the installed measurements match the published specs. In the Spider, for example, changes to the block deck height or cylinder head thickness or head gasket composition may change the "length" of the timing belt, and thus the cam timing. Remember we're talking about a few degrees and a few thousands of an inch. You can read about the steps necessary for proper cam installation here: https://www.lunatipower.com/Tech/Cams/H ... eACam.aspx. Not everybody does this, but your PO may have. This is the main purpose of adjustable cam wheels on our engines; to compensate for manufacturing tolerances and previous machine shop treatments. You should contact the PO and ask him if he has (1.) properly aligned the cam wheels with the pointers so that actual TDC is within one tooth of each wheel, or (2.) if he has installed and "degree'd" the cams as described above. #1 is general maintenance, #2 is tuning for best driveability and max performance.

Sorry for the ramblings, but there are semantics and conventions that are sometimes mis-interpreted. To answer your question, I would start with the cams set per the instructions linked above. If the PO has done this ... great, do a dyno pull and report the results. The tuner will be able to give you not only horsepower and torque numbers, but also air/fuel ratio and ignition advance. With these baseline numbers, you'll then be able to approximate your motor as-is vs. numbers generated by engines similarly-modified as yours. Remember the old axiom, "the last ten extra horsepower costs a lot more to make than the first ten."

Andy & I disagree about the benefits of lighter flywheels. If you are not replacing the clutch components or the transmission at this time, I'd leave the OE flywheel in for the time being and concentrate on optimizing the components already installed on your engine. BTW, Chris Obert lives in Santa Cruz, and he has a great deal of seat time in Spiders. Maybe you could get him to take your car for a spin and give you his impression of the motor, as well as the rest of the car.

Now I'm really going to mess with you I don't know how many old cars you own, but it is hugely expensive to make an old car perform anything like a new one, television shows notwithstanding. There are very few vintage Spiders running around out there that can out-perform a new Corolla. Even with your mythical +20 HP over stock, minivans will blow you away at a stoplight. Maybe the thing to do this year is just drive your well-running car. Heck, you live among some of the most beautiful scenery in the US.

[AndyVAS]

I would agree on tuning before changing any more parts. You won't get 20hp from tuning unless things are way out of wack but you may find some large numbers in odd places as the tuning brings everything into line.

[ward00]

Thanks for the heads up about Chris Olbert, I'll see if I can get in contact with him. I'll report back when I have my baseline. As for competing with Corolla, I have come to terms that off the line my car isn't geared/torqued for it. However, based on how the car performed during its 800 mile test run this weekend, I was more than impressed with it performance, and that was without redlining it. With another unknown amount of HP/torque in the 5-6K range, I'm going to have a rocket (relatively speaking), or at least a car I will be really happy with (albeit a really noisy one).

Thanks for all the feedback.

[Nut124]

With what you have, I agree you should be in the 120HP range but does you car run like it?

Have you done any performance bench marking with your 1800? Your car should do a low 16's 1/4 mile and easily top 115mph.

I have a 1800 car with a very similar setup, going to 44IDFs. I think 40's will be a limiting factor beyond 120HP.

The flywheel job will only allow the engine to respond to throttle faster when not in gear. This may speed up shifting etc in racing but will do nothing to add dyno power.

From where you are, if running right, any further gains will be in the 6000+ RPM range, IMHO.

[ward00]

Nut124
I haven't dyno/bench marked it or tried timed runs. Will be doing before doing any mods. You are are right about the flywheel. It doesn't add HP, but will improved timed runs. I have a set of 44s but first things first. As for 120 HP, after reading the Guy Croft book it seems that its at the low end of the range that my set up is capable of. After optimizing what I have I hope to get his estimate of 140HP. Have you done any 0-60 runs? What were your times if you have?