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hi everyone, its been a few months since last post but i do spend some time each day reading up on what going on in the group.

I had the opportunity to get my speedster on a chassis dyno a couple of weeks back. And wanted to get some feedback on the data.  Car runs very well but i am curious if what steps you might recommend to get a bit more Torque out of the existing engine.

Engine specs as i know them....

1915cc as supplied from VS back in 2010.

94 mm X 69

1.11 Rockers

I do not know what cam is installed.

Tri mill Hot Dog exhaust (with heater boxes)

New Weber IDF 40s (jetted using a wideband and a lot of road time.) Replaced the Empi  34s. that came on the car. by the way this had a significant improvement above 4k. rpm

Stock heads  no porting.

Results were about what i expected.

Max power = 67whp @ 3980 rpm Average power = 58whp. Based on typical  calculations this would be about 85-90bhp (at the crank).

Max Torque = 97.5 @ 3360 rpm Average Torque = 70

AF Ratio is pretty flat at 12-12.2 up to about 4800 then drops to around 11.

sorry for the crappy screen shot.

Dyno

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  • Dyno: 1915cc
Last edited by GomerP
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It sounds good Gomer, it might be a tad too rich. I like 12 to 12.5:1 at WOT all the way up. It will probably be difficult to get it there. You might try different air jets to lean the upper range. It sounds like the main jets are right on.

You might try 1.25 rockers for a little better breathing.

If you really want more you'll need different heads along with higher ratio lifters. But at that point I'd split the case and stroke it.

Dave, you've got it backwards. It's air fuel ratio, air comes first. A lower number indicates less air as in richer mixture.

Thanks Danny. I was reading up on ratio rockers as that is an easy swap. But honestly not sure what to expect as a result as i have had many a VW engine but never swapped the rocker ratios.

I will pick up some air jets and see if a size up makes any difference, unfortunate the shop that did the dyno work had a fire the week after i did this run and they lost the dyno machine and everything else in the shop so i wont ever be able to get an apples to apples run...

Dave, thanks for the comment: Danny is correct stoic is 14.7:1, pig rich is anything under 11:1, WOT ideal is something around 12:1. Cruse (steady speed) is another thing entirety and ill save that for another day..

@DannyP posted:

It sounds good Gomer, it might be a tad too rich. I like 12 to 12.5:1 at WOT all the way up. It will probably be difficult to get it there. You might try different air jets to lean the upper range. It sounds like the main jets are right on.

You might try 1.25 rockers for a little better breathing.

If you really want more you'll need different heads along with higher ratio lifters. But at that point I'd split the case and stroke it.

Dave, you've got it backwards. It's air fuel ratio, air comes first. A lower number indicates less air as in richer mixture.

Doh. When am I going to learn. “No posting before coffee!”

85-90 hp base 1915 is just about right. I concur with Danny: you'll get a little more with ratio rockers and a set of Panchitos. Maybe enough to make you happy if the new heads also up your compression ratio a half point or so. Think 110 @ 5,000 (85-88 wheel hp). Your torque numbers are already where they're going to be, so figure they stay about the same but peak moves up the rpm range 500 or 1000 rpm.

To make much more than that you'll be balancing the crank and doing other work and spending other money. At that point you buy the bigger crank. The new crank gets you to 2165cc. There is some machine work involved. Plus Panchos and a cam, strong rockers & etc. (beehive springs? Weber 44s?)  you can almost double your output.

It all depends on how fast you want to spend.

@GomerP

I'm a huge advocate for starting over - completely over. Spec an engine, put your money aside for new everything (tin, exhaust, intake, ignition). When it's ready, take your engine out, fog the cylinders, drain the oil and fuel, and put it in a construction garbage bag. Set the engine aside in case you ever have an issue. When the inevitable happens, you'll only be a couple hours away from being able to finish the season while you deal with whatever issue may have arisen.

It's belt/suspenders for sure - but failing to plan is planning to fail.

Compression and displacement give you grunt, along with high port velocity. With the right combo you can have grunt and top end.

A word of advise: new parts sometimes take a long while to get. Decide your path(parts) and have patience. Build it in late fall or winter if you're rebuilding.

CB took 8 weeks to make and ship me heads and port-matched manifolds. It took 3 weeks or so for a balanced crank/flywheel/pressure plate. Camshafts can be an even longer wait, I believe everyone's blanks come from Scat. Then they have to be ground, heat-treated, and polished.

Mahle stroker 94mm cylinders(B pistons) are still unavailable right now. I got the last set from Moore parts, nobody has had them since February. AA pistons are not for me.

Last edited by DannyP

@GomerP-

This may go against the flow a little, but bear with me.  Without building a whole new engine-

To make more power with what you have it will need to rev a little higher, since 90 hp at 4800- 5,000 rpm is about right for a 1915. As already mentioned, finish sorting out the jetting, install 1.25:1 rockers and if the heaterboxes really need to stay, get a proper 1 3/8" merged header (preferably sidewinder design), take off your heads and get them properly ported and (at the same time) figure out your compression ratio and get them fly cut if need be.  This would be a good winter project- start as soon as your driving season ends, taking the heads off and getting them to a head specialist.  Line someone up well before hand so you're not just dropping them off and waiting 'in the queue' for weeks and weeks (or months).

The advantage- you're using what you have and everything you're doing will be well matched to the camshaft that's in the engine (we don't need to know exactly what it is right now), and as Ed said, you'll be hitting somewhere around 110 crankshaft hp (that's 1500cc 4cam power) with about 500 more rpm than now and none of the lack of bottom end (and drivability issues) that the 4 cam engines typically had.  Carrera engines rev to 7,000 rpm with power and (especially the smaller displacements) really had nothing until the cam came on at 4500-5,000 rpm.  You could just slap some Panchitos on it but they are kind of wasted here as they won't provide anything near their potential (160 hp or so) and airspeed won't be quite as nice at off idle/lower rpm's as stock ported heads, which are perfectly capable of 120-125 hp.  You'll also get ever so slightly better mileage with the smaller valve heads- not that it's all that important, but it will tell you it's more efficient and the better combo.

To get a whole pile more power, as the guys have already said, you'll have to increase displacement by stroking it.  A 21-2200 cc beast with Panchitos, 1 1/2" exhaust and a cam/rocker combo that revs to 6,000 rpm and gives close to 1/2" valve will make 145 or 150 hp and be an absolute blast to drive! (think big, evil laugh here!)  Stan's advice of starting new and either selling the 1915 or putting it under the bench and Danny's words of wisdom are all spot on.  It won't be cheap, though, and as Ed said, we do love spending your money...

Hope this helps.  Al

Last edited by ALB

Oh Al.. now you got me second guessing.
what you noted is kinda what I was initially thinking I would get in the way of feedback.
so the thought process is start with rockers & port work. See if I am satisfied (hahahahah I am never satisfied that’s the point of this hobby) 110 Bhp is kinda what I have in mind for now. And of course I’d kinda like to push this engine a bit even if I do build another monster.  I do not know any good shops that I would trust to do port work on my existing heads. If anyone has a recommendation I am all 👂s.
question on rockers. If I am not changing the crank do I need new pushrods. I see a lot of conflicting info on the great inter web... if I go from say the 1.1 to 1.2+  
As for the heater boxes unfortunately they must stay if I want SO acceptance/ buy in. She asked asked a lot fewer questions about what I spend when she gets to enjoy the ride.  

exhaust is another question, I read that the tri mill hot dog I Have starts to be an issue anything north of 90bhp.

recommendations on merged header are welcome.  

oh this is going to be fun.. now I want to hop up the 1915 and start a fresh build.  Yes y’all are great at spending my $$$$

As far as heads are concerned, my take:

Performance comes from a combination of many things, but MAINLY from the heads.

I removed my considerably massaged 040 heads: 52cc chamber, 44 x 37, 68cc port volume, 10.2:1 heads with welded and port matched manifolds and had them rebuilt. New guides, a valve job, and one Tig weld on one valve end. Back in business for $500 plus my shipping there, almost $600. Probably the exact same time-frame as new heads.

You can get brand new Panchitos(40 x 35) for $600, add another hundred for port-matched manifolds. If you need the chambers cut it's less than another $100.

I'd buy new, you can't beat the flow numbers and port matched manifolds along with the bang for the bucks. Set the C/R in the low 9:1 range(deck height VERY important) and add those 1.25/1.3 rockers. You'd be less than $1000 into it for heads, rockers, and intake manifolds. The down time is minimal to swap. Don't forget 12mm 3/4" reach spark plugs, all the new heads have dumped the 14mm 1/2" reach threads that strip.

Get yourself an adjustable pushrod(cheap tool) and some rocker stand shims and be prepared to get new pushrods. Set the geometry the right way, there are youtube videos of how-to. You may be able to re-use but you have to mock it up to KNOW.

@GomerP posted:

hi everyone, its been a few months since last post but i do spend some time each day reading up on what going on in the group.

I had the opportunity to get my speedster on a chassis dyno a couple of weeks back. And wanted to get some feedback on the data.  Car runs very well but i am curious if what steps you might recommend to get a bit more Torque out of the existing engine.

Engine specs as i know them....

1915cc as supplied from VS back in 2010.

94 mm X 69

1.11 Rockers

I do not know what cam is installed.

Tri mill Hot Dog exhaust (with heater boxes)

New Weber IDF 40s (jetted using a wideband and a lot of road time.) Replaced the Empi  34s. that came on the car. by the way this had a significant improvement above 4k. rpm

Stock heads  no porting.

Results were about what i expected.

Max power = 67whp @ 3980 rpm Average power = 58whp. Based on typical  calculations this would be about 85-90bhp (at the crank).

Max Torque = 97.5 @ 3360 rpm Average Torque = 70

AF Ratio is pretty flat at 12-12.2 up to about 4800 then drops to around 11.

sorry for the crappy screen shot.

Dyno

@GomerP posted:

Oh Al.. now you got me second guessing.
what you noted is kinda what I was initially thinking I would get in the way of feedback.
so the thought process is start with rockers & port work. See if I am satisfied (hahahahah I am never satisfied that’s the point of this hobby) 110 Bhp is kinda what I have in mind for now. And of course I’d kinda like to push this engine a bit even if I do build another monster.  I do not know any good shops that I would trust to do port work on my existing heads. If anyone has a recommendation I am all 👂s.
question on rockers. If I am not changing the crank do I need new pushrods. I see a lot of conflicting info on the great inter web... if I go from say the 1.1 to 1.2+  
As for the heater boxes unfortunately they must stay if I want SO acceptance/ buy in. She asked asked a lot fewer questions about what I spend when she gets to enjoy the ride.  

exhaust is another question, I read that the tri mill hot dog I Have starts to be an issue anything north of 90bhp.

recommendations on merged header are welcome.  

oh this is going to be fun.. now I want to hop up the 1915 and start a fresh build.  Yes y’all are great at spending my $$$$

@Pat Downs Any advice you could offer this gentlemen regarding his desire for more power out of his anemic 1915cc?

CB or Berg for the merge header- but keep in mind that a merge header puts the collector pointing straight back, about even with the rear valance. Any kind of exhaust and you are hanging out the back. An A1 Sidewinder puts the exhaust on a right angle, so that everything fits, but it's expensive and you'll probably need to drop the muffler to adjust the valves. There is no cheap/elegant solution.

You're also right to worry that finding a head porter who knows what he's doing who would be willing to work on used heads (that he didn't sell). Unless all you are after is a "fluff 'n buff" (which won't really make the engine flow any better), I think you'd  have better luck finding a particular needle in a stack of identical needles. Good head guys are backed up for 6 months or more selling completed heads for their own particular program (Stage 1, Stage 2, etc.). If you could find somebody to do it, I'd wonder why- and even then, he'd want your heads for months and you'd be at the bottom of the pile.

Panchitos are $700/set with the CNCed chambers and dual springs. You'd be pressed to replicate that with somebody else.

We haven't talked about your crankshaft or cam.

... which gets us to why I'd just start over. I can almost guarantee that you have a stock, non-counterweighted crank, stock rods, and a stock cam. To turn more than 5000 RPM safely, you'll want at least a stock stroke counterweighted crank. If you are doing that, there's zero reason not to at least stroke it to 78 mm. With the case split, you'll want a different cam.

There's a sweet spot with these engines, and it's at 82 mm of stroke, stock length connecting rods, and "B" pistons. Do 90.5s, and you've got the 2110 that everybody loves. Use 94s and you have a 2276. A W120 works well with either, an FK8 works great with the bigger engine. You'll want a 1-5/8 header with either (although a 1-1/2 would work fine for the 2110) - but it doesn't matter since you're looking at a new exhaust anyhow.

... and you can see how just building something new makes more sense the longer you look at it. Alternately, you can fritter around trying to make a silk purse out of a sow's ear, as I've done repeatedly.

Or maybe you're like Jim Ignacio or Mitch Toll who have embraced the limitations of their cars, and learned to love them for their imperfections (or something).

I'm not that guy. As you are asking for more of your VS 1915, I don't think you are either. Everybody tries to find the middle road, to thread the needle and come up with a powerful engine on the cheap. It isn't out there, and I've tried. Don't be like Stupid Stan.

Buy once, cry once. 

@DannyP posted:

@Joe Fortino Pretty stout: 126hp @ 5500, 136ft./lbs. torque at 4000. I'll bet that was a nice drivable combo. I'll bet that was a forged counterweighted crank and rods, too.

I'm with Stan, either swap the heads/rockers like I said.

Or build new.

That looks like the same setup I got in my Spyder. Peak torque at 4k, peak HP at 5500. I believe those engines were all spec'd the same or very nearly so, rated at 120 hp and dyno'd between 123 and 126.

Bugpack 044 heads, Engle W125 cam? CR at 8.5 to 1?

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