rally cam test

[Graham]

As far as I am concerned that’s a 200 bhp engine, that’ exactly what Paul Gardner said happen on his engine, it briefly jerked over 200bhp and then dropped back a couple of bhp. Well done, time for the Pub for you now.

so what happens if you pull the 48's off the GTS4 equipped engine and slap on a 38 dgas? well you get the sort of power most oval racers claim, it drops from 197 bhp to 167, at this point i have to admit i gave the dgas a helping hand using a ported manifold and spacers between carb and manifold and manifold and head, but i the 3d printed stub stack did practically nothing but it looked faster, all told i was impressed, upto now best ive seen from a dgas was nudging 150bhp.

[Forest_rallying]

It’s nice to get back on a sensible discussion once again, it looked at one stage as though the Forum had died due to so few posts.

Is that the 200 bhp that F2 Stock Car engines have with their near standard heads? How does the engine seem to run on the single carb seeing the cam has such a lot of valve lift @ TDC? It would have been interesting to see what Kent’s GTS7, their ultimate Stock Car cam would have produced both with single and 48’s. I think a full 1 ratio compression increase would have seen both cams break the 200 bhp barrier on 48’s.

Merry Christmas, enjoy your Christmas Dinner and I’ll look forward to the next updates.

[Graham]

It’s nice to get back on a sensible discussion once again, it looked at one stage as though the Forum had died due to so few posts.

Is that the 200 bhp that F2 Stock Car engines have with their near standard heads? How does the engine seem to run on the single carb seeing the cam has such a lot of valve lift @ TDC? It would have been interesting to see what Kent’s GTS7, their ultimate Stock Car cam would have produced both with single and 48’s. I think a full 1 ratio compression increase would have seen both cams break the 200 bhp barrier on 48’s.

Merry Christmas, enjoy your Christmas Dinner and I’ll look forward to the next updates.

it ran just fine, sounded different, it seemed much more rev happy than with the lynx setup although it felt rougher but maybe thats just the difference in throttle set up transmitting different vibration to the the handle on the console, The lynx had more low down power and a higher peak number but the DGAS reved on better giving a more useful rev range, its now the 3rd time i have run the lynx maniold on a single DCOE, from all three tests i would say forget the lynx and keep the twinchoke or go with splits.

i dont have the numbers on my phone, but from memory, 38dgas 167bhp, lynx 173bhp, split 45's 183 bhp, that put the split 45's only 14bhp down on twin 48's, with more compression and yet more cam i could definatly see the splits getting close to 200bhp especially if they were switch for 48's.

[onecamohv]

the thing is cars are a very tribale affair, HT, Vulcan, Harris, SRD, Tovey, Grace developments to name a few, all have their followers who would refuse to belive any engine from anyone else could be any better or worth looking at, in the world of FB and Pub BS your never going to win.
.

Never a truer word spoken. it's as bad or worse over here.

It's a very very weird market to break into, even if you are doing much much better work than the 'go to' people....speaking from experience.

@Graham , any chance of throwing an RL31 in there for the hell of it ? I'd just like to see how it compares to the others on a base engine!
Great work as usual, love getting YouTube notifications of your vids 👍



Sent from my Pixel 7 Pro using Tapatalk

[Graham]

Never a truer word spoken. it's as bad or worse over here.

It's a very very weird market to break into, even if you are doing much much better work than the 'go to' people....speaking from experience.

@Graham , any chance of throwing an RL31 in there for the hell of it ? I'd just like to see how it compares to the others on a base engine!
Great work as usual, love getting YouTube notifications of your vids 



Sent from my Pixel 7 Pro using Tapatalk

i did run up an rl31 on 45's from memory it made 184bhp

[Graham]

every day is a school day they say. just to recap my 2.1 dyno mule fitted with a GTS4 and 48's was making 197bhp breathing through 40mm chokes attached to an as cast intake manifold ( its not matched to anything as i am always swapping it between head/engines)

The owner of the Harris engine asked my to run his 50mm webers up to check they were ok,

i didnt think i needed to as they worked on his tired giving 192bhp. however I agreed because i thought it would be a good idea to see how they performed on smaller chokes as they were fitted with 46mm!! and somewhat bizare 195mains and 120 air correctors, which goes to show they were too big. I switched them for 40mm chokes and ended up on 180 mains, 155 air, i dont think thats perfect yet but the power is there and the AFR is in the window, logic says 48mm/40 choke 50mm/40 choke wouldnt be that much different, they were on his manifold so stil not matched to my head but probably a better match than my manifold although it doesnt make the massive difference everyone says

Anyone want to guess the power difference..
..
..
..
..
.
..
.
.
.
.
.
.
.
.
.
.
.

.
.
.
.
.
.

.
.
.
.
.
.
6bhp, its now on 203 with a better torque curve than the 48's gave

[Graham]

[Forest_rallying]

Congratulations Graham, you have broken the 200 bhp barrier. Do the 48 carb chokes fit the 50’s or are they different. It’ll be interesting to see what the 50’s with 40mm chokes give on the 2.2 Harris engine when it’s rebuilt.

Is the big Simpson manifold still on the Dyno mule?

[Graham]

Congratulations Graham, you have broken the 200 bhp barrier. Do the 48 carb chokes fit the 50’s or are they different. It’ll be interesting to see what the 50’s with 40mm chokes give on the 2.2 Harris engine when it’s rebuilt.

Is the big Simpson manifold still on the Dyno mule?

48 and 50 chokes are same, ive also got some 38's but i suspect they will hurt power quite a bit on the 50's, will probably try them though in the final testing.

yes simpson manifold still on the engine.

i talked to the harris engine owner earlier, it was a bit topsey turvey conversation, although in the first place he thought 180bhp was plenty, he later went on to say he would love 200 bhp, i had to keep reminding him the brief was make it more drivable! then later on i told him his carbs had made 203bhp he said he wanted that, until i told him he would need nearly 7500rpm to get it, at which point he said no i dont want to rev it that hard, just give me a nice engine! so whilst i thought i had decided which cam i now having second thoughts, i was going to fit an Rl31, although the torque curve of the GTS5 is hard to ignore, it comes in a bit later than the rl31 so probably isnt as road friendly, but then again were on 50mm carbs so we will always be slightly short on grunt at the bottom end.

[Forest_rallying]

48 and 50 chokes are same, ive also got some 38's but i suspect they will hurt power quite a bit on the 50's, will probably try them though in the final testing.

yes simpson manifold still on the engine.

i talked to the harris engine owner earlier, it was a bit topsey turvey conversation, although in the first place he thought 180bhp was plenty, he later went on to say he would love 200 bhp, i had to keep reminding him the brief was make it more drivable! then later on i told him his carbs had made 203bhp he said he wanted that, until i told him he would need nearly 7500rpm to get it, at which point he said no i dont want to rev it that hard, just give me a nice engine! so whilst i thought i had decided which cam i now having second thoughts, i was going to fit an Rl31, although the torque curve of the GTS5 is hard to ignore, it comes in a bit later than the rl31 so probably isnt as road friendly, but then again were on 50mm carbs so we will always be slightly short on grunt at the bottom end.

I think the RL31 or BF63, even the WR40 would be ideal for the Harris engine, not too much overlap making it nice and drive able on the Road. I believe the GTS4 is nearer to a Race camshaft than Rally. He might even want to stick with his HT after all this.

I am off to the Workshop now on my days off to get back to fitting a Tracsport gear kit in a Type 9, I had blocker bars testing my patience yesterday.

[hawk1903]

48 and 50 chokes are same, ive also got some 38's but i suspect they will hurt power quite a bit on the 50's, will probably try them though in the final testing.

yes simpson manifold still on the engine.

i talked to the harris engine owner earlier, it was a bit topsey turvey conversation, although in the first place he thought 180bhp was plenty, he later went on to say he would love 200 bhp, i had to keep reminding him the brief was make it more drivable! then later on i told him his carbs had made 203bhp he said he wanted that, until i told him he would need nearly 7500rpm to get it, at which point he said no i dont want to rev it that hard, just give me a nice engine! so whilst i thought i had decided which cam i now having second thoughts, i was going to fit an Rl31, although the torque curve of the GTS5 is hard to ignore, it comes in a bit later than the rl31 so probably isnt as road friendly, but then again were on 50mm carbs so we will always be slightly short on grunt at the bottom end.

Hi Graham,
Is the tired 2.1 Harris engine fitted to a pure hillclimb car or is it a road driven hillclimb car ?
Which emuls tubes currently fitted ? They may have an impact on the low range. Do not you think so ?
50s have 4 prog holes versus the 48’s 3 prog holes which brings a certain tunability advantage on the low range when the carbs tuned on the car/on the road in my opinion. By the way, afaik some BDG rally guys use 50s 40chokes instead of the 48s with 42chokes due to that tunability advantage.
And may be worth noting, Harris heads might be considered one of the best non-raised port heads in the market as far as I have heard.

[Graham]

Hi Graham,
Is the tired 2.1 Harris engine fitted to a pure hillclimb car or is it a road driven hillclimb car ?
Which emuls tubes currently fitted ? They may have an impact on the low range. Do not you think so ?
50s have 4 prog holes versus the 48’s 3 prog holes which brings a certain tunability advantage on the low range when the carbs tuned on the car/on the road in my opinion. By the way, afaik some BDG rally guys use 50s 40chokes instead of the 48s with 42chokes due to that tunability advantage.
And may be worth noting, Harris heads might be considered one of the best non-raised port heads in the market as far as I have heard.

the tired harris engine is a 2.2, which explains why although my 11.3 cr 2.1 is making 11bhp more than the harris around 3500-4000 the harris engien with its 12.5cr and HT1 cam actually made more torque.

the Harris was in a pure hill climb car, its going going in a pure road car which might do the odd trackday. the 50's are fitted with F16's. its interesting what you say about the BDG and 50's because from the moment go i felt the engine was happier on the 40 choked 50's than the 48's or even big choked 45's. on the very first pull despite being pig rich it pulled 197bhp. Its stil rich low down and progression but i think a smaller set of pump jets will help that. Thats not a typo i did mean pump jets, looking down the carbs the engien is pulling a fair amount of fuel through the pump jets at part throttle.

Harris engines are a bit of a generic terms these days, the head i have was done by the now departed grandad, Ron Harris as far as i know. From what i understand the Harris clan have split and there is now more than one company building engines under the Harris name.

[FrankC]

HPE Motorsport and HARRIS Powerhouse I believe…

[Graham]

having broken 200 bhp once i cant stop myself now! i took the simpson manifold off and put an ashley 3 piece on, after a change of air correctors i got 207bhp, 166 lbft, torque curve isnt as good as the simpson, but given the cost difference...... Peak torque on the 3 piece is higher and it hangs on better hense the higher peak, i reved it onto 7500 where it still made 205bhp, going further resulted in a missfire, but i think thats the valve springs crying enough! the burton head came with heavy duty singles, i dont know exactly how many thines they have been to 7500rpm or more but its around 500.

so if anyone wants to know where the change over point between the small bore ashley and 3 piece is i can now tell you its somewhere around 190bhp

[FrankC]

“Like a dog with a bone” springs to mind lol.
It’s one thing to be curious as to how different cams compare but to take it as far as you’ve done at great expense to yourself, never mind the time involved, is above and beyond.
First class !

Take the rest of the day off…

[Graham]

[hawk1903]

the tired harris engine is a 2.2, which explains why although my 11.3 cr 2.1 is making 11bhp more than the harris around 3500-4000 the harris engien with its 12.5cr and HT1 cam actually made more torque.

the Harris was in a pure hill climb car, its going going in a pure road car which might do the odd trackday. the 50's are fitted with F16's. its interesting what you say about the BDG and 50's because from the moment go i felt the engine was happier on the 40 choked 50's than the 48's or even big choked 45's. on the very first pull despite being pig rich it pulled 197bhp. Its stil rich low down and progression but i think a smaller set of pump jets will help that. Thats not a typo i did mean pump jets, looking down the carbs the engien is pulling a fair amount of fuel through the pump jets at part throttle.

Harris engines are a bit of a generic terms these days, the head i have was done by the now departed grandad, Ron Harris as far as i know. From what i understand the Harris clan have split and there is now more than one company building engines under the Harris name.

50s with 40mm chokes might be a good combination with some rather high revving camshafts but do you think that it will work well with the lets say RL31, GTS5, BF63 type/range of cams ? 50s/40chokes may work against the nature of those cams around low-mid range. Then those cams are kind of the edge between the 3pcs large bore Ashley and small bore Ashley.

[Graham]

50s with 40mm chokes might be a good combination with some rather high revving camshafts but do you think that it will work well with the lets say RL31, GTS5, BF63 type/range of cams ? 50s/40chokes may work against the nature of those cams around low-mid range. Then those cams are kind of the edge between the 3pcs large bore Ashley and small bore Ashley.

honest answer, dont know! i do have some 38mm chokes for the 50's, so will probably try them when the actual engine is built.

to my mind the GTS5 and RL31 are close enough in the way they perform to make me think the simpson manifold will work with the RL31.

[hawk1903]

honest answer, dont know! i do have some 38mm chokes for the 50's, so will probably try them when the actual engine is built.

to my mind the GTS5 and RL31 are close enough in the way they perform to make me think the simpson manifold will work with the RL31.

Worth testing 50s with 38mm chokes. Actual engine, do you mean the 2.2 Harris ?
Afaik, there are the small bore and large bore Simpson. Which one you are using during the tests ? I would be grateful if you could tell us the lenghts and tube IDs or ODs at your convenience please.

And I would imagine tuning ( leaning in this case ) the low down and mid range could help a lot. Whenever we concentrate on tuning the low down and the mid range our BDG performs better. But of course, having the carbs tuned on the car under certain atmospheric conditions under actual rally stage conditions etc etc is a different. Gearing, wheel spin etc also has a considerable effect on the low down tuning according to our experience.

[Graham]

Worth testing 50s with 38mm chokes. Actual engine, do you mean the 2.2 Harris ?
Afaik, there are the small bore and large bore Simpson. Which one you are using during the tests ? I would be grateful if you could tell us the lenghts and tube IDs or ODs at your convenience please.

And I would imagine tuning ( leaning in this case ) the low down and mid range could help a lot. Whenever we concentrate on tuning the low down and the mid range our BDG performs better. But of course, having the carbs tuned on the car under certain atmospheric conditions under actual rally stage conditions etc etc is a different. Gearing, wheel spin etc also has a considerable effect on the low down tuning according to our experience.

yes by actual engine i mean the 2.2 harris which is what the 50's belong on. The last and only other 2.2 i built which at least 15 years ago i fitted with RL31 and 45mm jenveys. That made 200 bhp flywheel on two different reputable rolling roads. ive run a couple of RL31's since but not seen anything like that sort of power. But these tests show i have a good chance of repeating that 200 bhp on the harris with that cam. The 2.1 using small bore ashley manifold and 45's showed 184bhp with it, if you assume the gain the simpson manifold gave on the GTS5 would be similar on the RL31, along with the gains from the bigger carburation then scale up for the extra capacity of the 2.2 then the rl31 should see 200bhp.......................

[Forest_rallying]

yes by actual engine i mean the 2.2 harris which is what the 50's belong on. The last and only other 2.2 i built which at least 15 years ago i fitted with RL31 and 45mm jenveys. That made 200 bhp flywheel on two different reputable rolling roads. ive run a couple of RL31's since but not seen anything like that sort of power. But these tests show i have a good chance of repeating that 200 bhp on the harris with that cam. The 2.1 using small bore ashley manifold and 45's showed 184bhp with it, if you assume the gain the simpson manifold gave on the GTS5 would be similar on the RL31, along with the gains from the bigger carburation then scale up for the extra capacity of the 2.2 then the rl31 should see 200bhp.......................

How far off completed build is the Harris engine Graham? Are you intending to do a couple of camshaft tests on it when it hits the Dyno or are you going to let the customer decide having seen the conclusion of the 2.1 results? Could this be an engine that we see over 215bhp.

[Graham]

How far off completed build is the Harris engine Graham? Are you intending to do a couple of camshaft tests on it when it hits the Dyno or are you going to let the customer decide having seen the conclusion of the 2.1 results? Could this be an engine that we see over 215bhp.

a fair way off yet. its not my intension to be swapping cams around when the Harris engine is back togther unless i find the RL31 im going to install really doesnt work. The brief for the Harris engine was make it more drivable not give it more power, the owner says he doesnt want to drive like a pratt or use 7500 rpm. so i think a fresh engine, less cam and a better head i can give him more power and driveability than he had before, iuf he ends up with 215bhp something is wrong!

[Forest_rallying]

a fair way off yet. its not my intension to be swapping cams around when the Harris engine is back togther unless i find the RL31 im going to install really doesnt work. The brief for the Harris engine was make it more drivable not give it more power, the owner says he doesnt want to drive like a pratt or use 7500 rpm. so i think a fresh engine, less cam and a better head i can give him more power and driveability than he had before, iuf he ends up with 215bhp something is wrong!

It’ll be interesting to see what compression you decide on for the RL31, the only problem I can see is if the customer wants to go back to a long duration Race cam after the compression’s set for the RL31 then it won’t be that easy to increase the compression again. I think the 31 should have ideal Road manners especially if the car has the correct gearing.

[Graham]

It’ll be interesting to see what compression you decide on for the RL31, the only problem I can see is if the customer wants to go back to a long duration Race cam after the compression’s set for the RL31 then it won’t be that easy to increase the compression again. I think the 31 should have ideal Road manners especially if the car has the correct gearing.

my dyno mule is 11.3 and seems happy at that on the RL31, wanting peak advance of 30 degrees, so i see no reason to use anything different. The cars hillclimb days are past it. They were with a previous owner.

[hawk1903]

There is a vast amount of extremely valuable information accumulated in this thread.
So at a certain stage, one of us should try to make a user friendly database including Graham’s remarks.

I am wishing you all a Happy, Healthy New Year !!!

All the best

[Graham]

There is a vast amount of extremely valuable information accumulated in this thread.
So at a certain stage, one of us should try to make a user friendly database including Graham’s remarks.

I am wishing you all a Happy, Healthy New Year !!!

All the best

thanks bit by bit it will all end up on you tube, so i can try to get some of the cost back, so if you can all get my channel on your computers and tv's playing 24/7 id be greatful

ps i have a video uploading now

[Forest_rallying]

thanks bit by bit it will all end up on you tube, so i can try to get some of the cost back, so if you can all get my channel on your computers and tv's playing 24/7 id be greatful

ps i have a video uploading now

Can you put a link to the video sometime please Graham?

[Graham]

Can you put a link to the video sometime please Graham?

this video is gts4/5 carb, exhaust swaps

https://youtu.be/0hIWk4X8w2w

[rallyrob]

this video is gts4/5 carb, exhaust swaps

https://youtu.be/0hIWk4X8w2w

Wow. The 3 piece Ashley was a big surprise, wasn't it!!

I've got a 3pce manifold on my engine, but it probably only makes about 185bhp.

Not sure as it was nearly 30 years ago it was on the rollers and I honestly can't remember if it was 160 or 165 at the wheels.

How would you recalculate that?

[Graham]

Wow. The 3 piece Ashley was a big surprise, wasn't it!!

I've got a 3pce manifold on my engine, but it probably only makes about 185bhp.

Not sure as it was nearly 30 years ago it was on the rollers and I honestly can't remember if it was 160 or 165 at the wheels.

How would you recalculate that?

yes the 3 piece certainly was a suprise, you would have to think the Simpson a better choice for road/rally use unless you take the price into account.

[rallyrob]

yes the 3 piece certainly was a suprise, you would have to think the Simpson a better choice for road/rally use unless you take the price into account.

Yes, the Simpson is expensive certainly compared to a 3pce Ashley.

[Graham]

Yes, the Simpson is expensive certainly compared to a 3pce Ashley.

i almost didnt test the 3 piece either!

[rallyrob]

i almost didnt test the 3 piece either!

The only thing the Simpson has going for it is it's stainless. But I'd still rather have the Bhp over the stainless manifold.

[Forest_rallying]

The only thing the Simpson has going for it is it's stainless. But I'd still rather have the Bhp over the stainless manifold.

The Simpson manifold certainly has the beauty with its workmanship, but you can’t knock the performance of the 3 piece Ashley. I wonder how the SRD manifold would have faired in the tests Graham?

[hawk1903]

There should be small and large bore Simpson afaik.
Which one we are using for the tests ?

If anyone has SRD in hand and if we know the dimensions of the Graham’s Simpson, we may be able to guess I would imagine.

[Graham]

The Simpson manifold certainly has the beauty with its workmanship, but you can’t knock the performance of the 3 piece Ashley. I wonder how the SRD manifold would have faired in the tests Graham?

dunno but i do have an SRD manifold, trouble is i need to do some work not more dyno tests!

[Graham]

There should be small and large bore Simpson afaik.
Which one we are using for the tests ?

If anyone has SRD in hand and if we know the dimensions of the Graham’s Simpson, we may be able to guess I would imagine.

i think its the small one, but it is old so may not be 100% representative of the manifolds currently for sale

[hawk1903]

The Simpson manifold certainly has the beauty with its workmanship, but you can’t knock the performance of the 3 piece Ashley. I wonder how the SRD manifold would have faired in the tests Graham?

From the forest rally car perspective, would not you prefer the Simpson against the 3pc Ashley ? The mid range torque is better.
But, I think we would not prefer to use GTS4 in a forest engine and RL31, BF63 or the GTS5 could be a better cam for the purpose.

So far, based on Graham’s extensive study, what will be your cam, carb and exhaust combination for the typical forest stages but with shortish straights and lots of medium character corners ?

[katana]

Not sure as it was nearly 30 years ago it was on the rollers and I honestly can't remember if it was 160 or 165 at the wheels.

How would you recalculate that?

Don't think you can once you've left the rollers! The 'crank' figure is generated via the rollers 'driving' the wheels and transmission on spin down to estimate the losses in the drive train. I'm usually quite sceptical of 'engine HP' obtained from a RR. Bike dyno's stopped trying to quote 'crank' HP donkeys years ago as its an irrelevant number compared to the actual power making the vehicle move! I guess some people like a big headline type number for the pub - 200bhp ! ! ! is not the same as 150hp @ the wheels from 2300cc say!

[Graham]

From the forest rally car perspective, would not you prefer the Simpson against the 3pc Ashley ? The mid range torque is better.
But, I think we would not prefer to use GTS4 in a forest engine and RL31, BF63 or the GTS5 could be a better cam for the purpose.

So far, based on Graham’s extensive study, what will be your cam, carb and exhaust combination for the typical forest stages but with shortish straights and lots of medium character corners ?

from what ive seen, i would be using GTS5 simpson and 45's