3.1 engine done now...

[Sylv1]

Ok, Sean

I stop the discussion because... at the end, I would finish not to be sure to understand/write english

When I will have figures, you know I will tell you.

before that, it is just blabla

 

[Dave J]

Just deleted all the text I had written, because now I have pissed of a mate just keep me out of it in future please Sean.

 

[vpulsar]

On the odd ocasion that I have a read through the forum much of what he starts and writes makes me CRINGE like it must to a lot of you.
Sorry about that Thanks DJ

That has to be the most sensible thing written on the forum for ages :lol::lol:, I've not been a member for long but even I've worked out Sean talks out his arse most of the time , I'm sure their is a padded cell with a missing patient somewhere in the country .





Rob

 

[SeanDezart]

Don't care what people say or write about me, especially if they don't know me and don't know the facts and I promise to run down the next ginger-being breathing in front of me.......

I do believe that Ian P. owes Dave J an apology and please make it a public one !

 

[vpulsar]

I promise to run down the next ginger-being breathing in front of me.......

Maybe you're not as mad as I thought Sean .




Rob

 

[SeanDezart]

injected - you know that

Sorry - forgot ! You might have changed your mind or budget too........

vpulsar :

had a look up my orifice and can confirm - no ginger pubics ! Why don't you get yours over here in your Z and then slag me off face to face over a large glass ? Le Mans is in June.

 

[vpulsar]

Why don't you get yours over here in your Z and then slag me off face to face over a large glass ? Le Mans is in June.

You know if my car is ready by June and I can afford the trip I'll take you up on that my old mucker .





Rob

 

[SeanDezart]

You know if my car is ready by June and I can afford the trip I'll take you up on that my old mucker .
Rob

too many ifs there....... fly over or get the train and I'll collect you at the station !

Going back to the thread - why is it Willie is asking £8000 (€12000) for a Rebello engine when Ian is quoting €8000 ? Maybe it has more power - but then I know of a UK engine builders' engine that was about the price quoted but produced over 300bhp on a rolling road - no turbos !

Sliding on, does Dave R produce injected L series engines ?

 

[Rob Gaskin]

Irrespective of what any other engine can deliver, that one of Willie's is very impressive. Have you seen it in action Sean? I watched it on Motors TV and the ease at which Willie was able to power away from the competition was incredible.

No need to discuss bhp figures when you see it in action. The same car and driver with a 'normal' modified L series (2.8) now installed is amongst the front runners of his championship, previously he was in a different league.

 

[STEVE BURNS]

Don't want to get dragged into this but what Willie is asking for his engine is what Willie is asking for his engine and yes we know you know about another engine builder already

 

[samuri-240]

yes we know you know about another engine builder already

Who's that then ? :lol::lol:

 

[SeanDezart]

Irrespective of what any other engine can deliver, that one of Willie's is very impressive. Have you seen it in action Sean? I watched it on Motors TV and the ease at which Willie was able to power away from the competition was incredible.

No need to discuss bhp figures when you see it in action. The same car and driver with a 'normal' modified L series (2.8) now installed is amongst the front runners of his championship, previously he was in a different league.

Yep, so good - they banned it ! We have Sky and Motors TV here too Rob - thanks.

Have exchanged words with Willie AND Brian Morris in his Z - heard of him ?

Brings up another subject and I confess I know not the answer (hence the question here towards those that might know and have spoken to Dave R.) -

how many Rebello engines are powering circuit and rallye Zs in strictly controlled FIA or similar events ?

 

[Sylv1]

Going back to the thread - why is it Willie (...) Maybe it has more power -

Yes it has. It is not the same variant. Willie has the race one with high comp ratio, hotter camshaft and what follow.

Don't care what people say or write about me

Happy to read this... was upset that you would be offensed
You know, sometimes you go a bit far my friend ;o)

 

[Ian Patmore]

the Nismo 1" 5/8 versus the 1" 3/4 and found a huge differance....the 1" 3/4 needed a totally differant engine profile as the gas speeds were just not sufficient to induce scavenging where as the smaller primaries of the first system helped maintain the gas speeds and promoted scavenging.

Steve, do you think that this applies to larger cc engines (than your 2.8 [which I presume the test was done on]) as these would require a slightly larger amount of fuel to run properly, and thus more gasses? Or is my logic ascew. Also, what sort of increase did you get by adding your airbox?

Sean, running 48mm Dellorotos, and happy to have a glass of vino at Le Mans as I do hope the car is ready.

I do believe that Ian P. owes Dave J an apology and please make it a public one !

I gather from speaking to the moderator at the weekend that Dave has asked for a couple of bits to be removed/altered (which I have gladly) and on the whole Dave is content with what I have written. Dave has offered to speak to me, and I will seek Dave out to have a chat when I next see him at a Z CLUB do. There we can have a chat about anything we like, as a couple of adults, whether in agreement or a difference of opinion. Sean, most of what I have written is my opinion, so don't see the reason to apologize, especially as you have been the one doing the chirping on "Dave's behalf" much to his disgust. Leave. I will chat to Dave myself.

I promise to run down the next ginger-being breathing in front of me.......

That will be me then??!!

Yes, Dave Rebello does injected L series and turbos and 4 pots, V8's, v10's anything with an car engine......as for FIA events you will have to do some homework (including the whole Rebello company and its work), though bear in mind the majority of his customers are based in the US.

Regards
Ian

 

[SKiddell]

Hi Ian

There are a number of other factors involved in the exhaust system such as collector design and positioning, overall system design etc but personally I really believe that the exhaust system is one of the most overlooked and underestimated areas of tuning on NA engines as nearly everyone looks at carbs and cams first then slaps on a header almost as an afterthought.

The overall CC of the 2.8 will work ok with the 1" 3/4 as long as the cam is suitably designed (larger overlap, greater scavenging) coupled with this is a raise in compression (more aggresive cam profiles reduce the dynamic compression requiring either a thinner gasket or a head shave)

Rule of thumb says that the 1" 5/8 is more suited to the 2.4's and 2.6's (potential volumetric flow is lower) as the smaller primary bore helps keep gas velocity and scavenging high, on a like for like engine, increase the primary bore size by a few mm and exhaust gas speed will drop by a considerable amount, subsequently on the cam overlap period scavenging decreases, the result is that the incoming charge has less velocity, the cylinder doesnt empty out the spent gasses fully leaving a higher amount of residual spent gas polluting the incoming charge, flame front speeds and cylinder fill are down you could even have the scenario whereby the inlet speeds are so reduced that the fuel begins to partially drop out of suspension in the inlet tract (low engine speeds).....how many people have slapped large triples on a relatively stock engine only to be suprised that fuel economy goes down along with driving pleasure. You can see now how the induction system, head flow, chamber/port shape/size, compression ratio, cam design and exhaust system are criticaly interelated to one another.... alter any one of these and the overall harmony of a well tuned engine can/will become unbalanced. The entire tract from start to finish must be considered/designed as an entity to get the best out of the engine.

Also, what sort of increase did you get by adding your airbox?

The airbox helps in all of this by helping to reduce reflected inlet pulses off the near side inner wing which set up shock waves that interfer with the air entering the adjacent carb/TB mouths which directly affect the value of the air fuel mixture which of course affects power.... plus significantly helping to keep inlet temps down (cooler air is more dense, dense air = more O2, more O2 = greater potential for power) If I run without an airbox, inlet temps run at around 50+ degrees C the airbox reduces this by some 15 to 20 degrees depending on the day.

 

[ZHead]

Now I know why I am involved with IT not tuning

 

[SeanDezart]

Sean, most of what I have written is my opinion, so don't see the reason to apologize, especially as you have been the one doing the chirping on "Dave's behalf" much to his disgust.

Glad to hear that you'll speak to Dave however rare it is that he attends a Z Club do - you'd have a much better chance of meeting him at an HSCC race ; I think that that could only be constructive and perhaps overdue.



For the rest above, let's agree to disagree and move on !

That will be me then??!!

Didn't know and since Le Mans is a long way off, it's unlikely that you'll be the first I cross





Yes, Dave Rebello does injected L series and turbos and 4 pots, V8's, v10's anything with an car engine......as for FIA events you will have to do some homework (including the whole Rebello company and its work), though bear in mind the majority of his customers are based in the US.

I said FIA or similar, meaning fully scrutineered National/International track racing and not just club or track days. Hoping you might have some info to hand ?



Special comment for my friend Sylv1 : I'm VERY passionate and you'll all have to take the good with the bad.



I waited and saved up 9 years for this Z and engine (and I am righly proud of it and it's maker) after my first Z was effed up by someone reccomended with the wrong parts supplied by another reputable engine builder then effed up again and almost put me off another Z ! Sounds familiar ? We should have been discussing via PM since a while Ian and avoided all this tête à tête - I always said that you had pertinant points but regretted that you'd chosen a DJR subject thread to voice them !

Are we saying then that an airbox on carbs IS better than air filters ? Should one be 'afraid' of 'forced' air (under track speed) with carbs. and place a plate in front of the single big air filter ?

Has Dave R. given any advice upon this ?

 

[SKiddell]

Are we saying then that an airbox on carbs IS better than air filters ? Should one be 'afraid' of 'forced' air (under track speed) with carbs. and place a plate in front of the single big air filter ?

Yes, a PROPERLY designed airbox IS better than individual filters as an airbox helps induct cooler air plus when used with a filter it will clean the air as well as the individual filters and as mentioned before it will help reduce the reflected pulses that are often seen on air horns in close proximity to bodywork.

Now lets deal with the area of pressurising the airbox and let’s get some science in here shall we not myths and hypepole, lets not confuse cold air induction, with forced air induction
To class as forced air induction a significant rise in air pressure (several psi) must be demonstrated

Here’s the formula to calculate increase in air pressure if anyone wants to work it out

dP / P = (v2) / (2RT)

This would yield (at 100 mph) a pressure rise of 0.18 psi or 1.25 more than atmospheric pressure……or if we are talking meteorological language…..12.4 millibars…..you can get that sort of change in between morning and night, or driving up and down a 500 foot hill
Whoppee flippin doo….hardly “significant”

Taking that into account you would need well over 200 mph to generate way less than 1 psi once again hardly “significant”

So we have a potential increase of say < 0.5 psi BUT the air box isn’t sealed…it is deliberately designed not to be so that pressure change is even less, (try inflating a beach ball that has a hole in it) to add to this the fact that the air intake end isn’t directly in line with the axis of travel so air is hitting it at an angle…. further reducing the potential pressure rise….even less “significant”

Are you going to stop driving on windy days just in case the air pressure generated causes the world to stop spinning?

Finally lets not forget that the original 240Z came with an airbox…..a bloody great big orange one……a significant amount of high performance Japanese carb’d L6’s use aftermarket airbox’s (I seem to remember one of Alans cars with a white one on)

I am sure there’s more but I can’t be bothered to get drawn any more on this, if you can’t see it for yourself then the sky will fall in and the earths still flat.
http://www.volkszone.com/VZi/showthread.php?t=67837&page=2

 

[Charlie Boy]

Steve, are you still making your air boxes or have you retired?

My carbs are all naked and need a nice box to breath from, please

C

Yes, a PROPERLY designed airbox IS better than individual filters as an airbox helps induct cooler air plus when used with a filter it will clean the air as well as the individual filters and as mentioned before it will help reduce the reflected pulses that are often seen on air horns in close proximity to bodywork.

Now lets deal with the area of pressurising the airbox and let’s get some science in here shall we not myths and hypepole, lets not confuse cold air induction, with forced air induction
To class as forced air induction a significant rise in air pressure (several psi) must be demonstrated

Here’s the formula to calculate increase in air pressure if anyone wants to work it out

dP / P = (v2) / (2RT)

This would yield (at 100 mph) a pressure rise of 0.18 psi or 1.25 more than atmospheric pressure……or if we are talking meteorological language…..12.4 millibars…..you can get that sort of change in between morning and night, or driving up and down a 500 foot hill
Whoppee flippin doo….hardly “significant”

Taking that into account you would need well over 200 mph to generate way less than 1 psi once again hardly “significant”

So we have a potential increase of say < 0.5 psi BUT the air box isn’t sealed…it is deliberately designed not to be so that pressure change is even less, (try inflating a beach ball that has a hole in it) to add to this the fact that the air intake end isn’t directly in line with the axis of travel so air is hitting it at an angle…. further reducing the potential pressure rise….even less “significant”

Are you going to stop driving on windy days just in case the air pressure generated causes the world to stop spinning?

Finally lets not forget that the original 240Z came with an airbox…..a bloody great big orange one……a significant amount of high performance Japanese carb’d L6’s use aftermarket airbox’s (I seem to remember one of Alans cars with a white one on)

I am sure there’s more but I can’t be bothered to get drawn any more on this, if you can’t see it for yourself then the sky will fall in and the earths still flat.

 

[SeanDezart]

.......if you can’t see it for yourself then the sky will fall in ........

call me Chicken Little just want to be sure for a possible project for which I can't use injection ! I think Sylv1 would also be reassured for the airbox/carb. treatment.