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General FI questions - Rod strength and supercharger whine

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On 6/20/2019 at 6:20 PM, Graham86 said:

I've bought a Cosworth kit from them direct, about a month ago. It's a very good kit and support. You do get some whine and can be heard fine with the stock exhaust. I've gone for the smaller pulley and there's no overheating issues.

Regarding the Cosworth whine, since I removed the under bonnet insulation, the whine is much more noticeable, especially during routine town driving.  Very enjoyable!

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Not meaning to thread hijack (but it's relevant). What made people choose the Cosworth supercharger over the Harrop kit or vice-versa?

I've been doing some research on both and am really struggling to decide between the two. The larger blower of the Harrop kit looks to give more headroom for future mods but the smaller blower in the Cosworth kit gives less parasitic loss.

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On 6/11/2019 at 6:31 PM, Lauren said:

Yes it is or over-sizing the crank pulley is the other way. The tough issues is insuring that the intercooling is up to the job as there will be increased heat generated especially if you start to over drive the supercharger. 

Its a proportional thing. The Cosworth Kit runs +15C over ambient on track. The cooling system is specified for 380hp, hence being so low iat. 

The smaller pulley adds 0.1bar boost, raising it to 0.6Bar of boost. ~20hp. Its so small that you are hard pressed to see the difference in intake temps. 

Running 380hp would mean 1bar boost and +30C intake temps, roughly doubling them over the normal stage 2 setup. 

 

On the whine, since adding the smaller pulley mine has a subtle whine. With the normal pulley that comes with the kit, it wasn't noticeable for me even with stock exhaust.

 

The Edlebrock and Harrop spin slower and unlikely to whine. 

 

On the issue of rods. 

Even the few rods the guys at Cosworth tested would work at cylinder pressures that would be approaching 350hp, but then they used their data from OEMs to set the 280hp point to allow for manufacturing tolerance.

In essence if you tested a large number of rods from multiple batches, you would get a normal distribution around the mean strength. The way you set the power, is such that the probability of one failing is within acceptable limits. e.g. had they set it at 320hp, they might have found 1 in 10 cars eventually would fail. Unacceptable and dial it back until the probability of failure is lower. 

On top of that, if they ran the car at the max pressure the rods could take and somehow it develops knock bye bye rods. So setting it at 280hp gives headroom taking into account all the variables in manufacture and possible failure modes when installing or tuning the kit.  

This is why OEMs make stock rods that a typically capable of much more than stock power... typically. A dodgy Friday afternoon batch with a massive crack inside might not handle  190hp...

So yes you can take a gamble and run 350hp but there are plenty of blown FA20s on less power than that on the ft86club. 

 

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380hp SC build in addition for more then advised built engine with strenghtened internals to match also needs uprated clutch, gearbox (heard too often term of grenading gears fir higher power FI builds) and axles. If one takes into account additional costs of accompanying mods, choosing modest boost makes lot of sense.

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4 hours ago, Neil-h said:

Not meaning to thread hijack (but it's relevant). What made people choose the Cosworth supercharger over the Harrop kit or vice-versa?

I've been doing some research on both and am really struggling to decide between the two. The larger blower of the Harrop kit looks to give more headroom for future mods but the smaller blower in the Cosworth kit gives less parasitic loss.

Hello Neil

I chose Cosworth over other options after a test drive in a Cosworth kitted car.  I have driven other cars with another kit, although not a Harrop.  So I can't help you with a decision, but that wasn't your question.

After the test drive I looked into the development undertaken by Cosworth, who I have always admired regarding their engineering credentials.  I noted the hours on a test bed, and the fact that the map provided was regarded as "safe".  I also admired the fact that the installation looks very OEM in the engine bay, and that it seemed the aftercare was likely to be very good, and so it has proven. 

Matt at Cosworth is very prompt in dealing with any queries, and made sure that the map I had was absolutely suited to the exhaust options I had on the car.  I have had the Cosworth kit now for 3.5 years and it has been completely reliable, and looks like it was installed yesterday.  The materials used in the construction of the kit are top notch, and many engineers, on inspection,  have admired the quality of the design. 

It's more expensive, I believe, but I like to think you get what you pay for.

I can't comment on the qualities of the Harrop, but know that there are many satisfied owners.  

Good luck with your decision.  

 

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I've had three turbo cars and one with a supercharger.  The turbos all, to a greater or lesser extent, had that 'dead' lag followed by a big shove way of working.  The supercharger just gave a good slug of extra torque from low revs and was more progressive.  My BRZ is my daily driver for the 60-mile commute each day.  I can't help thinking that a supercharger will be the better option for me.

I've looked closely at the Cosworth and the Harrop.  I eliminated the Sprintex as, although great fun, it's hardly stealth and I don't want my car to be any noisier than it is (my CR-Z had a Sprintex).  Then there's the TD turbo, but the installation time is a week and they are 4 hours away.  Most of the superchargers need 1-1.5 days for installation and the installers are much closer to me.  Fensport have a Cosworth in stock and I'm talking to Mike at Abbey Motorsport tomorrow about the Harrop.  Both will provide around 280bhp with a big torque increase - perfect for road driving.

I'm just gathering my thoughts on what I might do next.

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Keep us updated on which way you go. By the time I get round to it, it'll probably just be the harrop available but always interesting to see which way people go and why

Sent from my CLT-L09 using Tapatalk

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I was speaking to a trader a couple of weeks ago about a number of things, including supercharging. He then informed me that Cosworth only have 8 supercharger kits left available in the UK. 

When I go FI it'll most likely be the Harrop (there are a number of reasons why I prefer it over the Cosworth), for those that are interested your are looking at just under £6k fully fitted and mapped (including new engine oil) for the Harrop from Abbey. 

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I wouldn't part from my Cosworth charger, after having to make a similar choice. I fitted it myself about 6 months ago and and from an engineering point of view, it's very good indeed. Very good support too.

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2 hours ago, matrixprotein said:

What makes you choose harrop over cosworth @will300

Here are a couple of the reasons:

Design:

a. I don't like the throttle body position on the Cosworth.

b. The Cosworth in-take pipe looks cheap and I've seen several people have issues (not with the in-take pipe) and have to remove it, its then a pain to refit.

c. You need to cut a small section out of the bonnet for the Cosworth in-take pipe to fit, at the back by the throttle body.

d. The Harrop is a one piece design whereby they have made the intake manifold and supercharger housing as one. On the Cosworth system they have basically bought the Supercharger and bolted a intake manifold on top (I appreciate it's not quite that simple). 

e. The Harrop has a lower profile due to its design.

f. The Harrop doesn't require a coolant bottle and the intercooler pump is hidden. 

Performance: 

a. The Harrop uses the TVS1320, which has been proven to produce over 400HP on our platform. I'm sorry Cosworth you haven't shown us any actual dyno graphs showing 380HP (not that I can remember seeing). If I end up going built motor I'll want the capability to run atleast 400HP.

b. To increase the power on the Harrop you simply buy a smaller pulley, there are 95mm to 65mm options. With the Cosworth you need to mess about with crank pulleys etc. 

Cooling:

The Cosworth wins on this front, but the differences are only marginal and there are a couple of options available to improve this on the Harrop. 

I've seen both system run on track at the same time and and perform flawlessly, so I know they are both efficient in this regard. 

Tuning: 

There is no difference is tuning, sure you have all the development done by Cosworth to develop a safe map but Matt (Cosworth) has only got the same tuning platform (Ecutek) to work with as Adrian (Fensport), Mark (Abbey) & Mike (TD) and Adrian & Mark have acknowledged that they've worked with Matt to develop various maps for different cars.

Cost:

They both work out to be about the same at the moment.

 

That's all I can think of at the moment, please bare in mind that these are my opinion, I'm sure some won't agree but they are the deciders for me. I'll also say, I was booked in to have a Cosworth SC fitted at one stage, but changed my mind because at the time I didn't want to spend the money. 

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16 hours ago, Church said:

380hp SC build in addition for more then advised built engine with strenghtened internals to match also needs uprated clutch, gearbox (heard too often term of grenading gears fir higher power FI builds) and axles. If one takes into account additional costs of accompanying mods, choosing modest boost makes lot of sense.

When you get to that level of modification and investment it just makes more sense to buy a faster car in the first place.

280bhp is the sweet spot, that's about 225bhp per ton which is perfect for a road car, after driving Abbeys Harrop charged car around Oxted it definitely doesn't need any extra, more than enough. In my opinion of course.

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18 minutes ago, Varelco said:

When you get to that level of modification and investment it just makes more sense to buy a faster car in the first place.

280bhp is the sweet spot, that's about 225bhp per ton which is perfect for a road car, after driving Abbeys Harrop charged car around Oxted it definitely doesn't need any extra, more than enough. In my opinion of course.

100% agree. Lotus Exige 350 V6 would be my other motor to compliment the gt86. 

 

 

 

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I agree with some/most of the bits Will is saying but I will add a few (try to be non biased) to that.

Design c. I am not aware of anyone needing to cut a section, but yes you may need to put a small dent using a ball peen hammer.

Design e. Due to it compactness the intake runner lengths are not tuned properly. They are too short. This is one of the reasons why the Cosworth running 0.5bar makes the same power as the harrop running 0.7bar boost. The other reason is the bigger more draggy TVS and the tuning to balance cylinder pressure which can only be done with incylinder pressure sensors (standard tunnig with OEMs and serious motorsport).

Performance e. Its a fair point the most powerful Cosworth is their dev car running ~330hp. However, I am not aware of high power 400hp harrops that use pump gas? All E85 which help massively with high IATs. General advice I see is 12psi max on pump and you need E85 if you go for more boost due to heat and pulling timing. 

Cooling: Yes at 280hp both are fine, but running high power is where is were the nearly twice as good cooling (Coswroth is +15iat, harrop +25iat, Edlebrock +30iat) would come into it. Where the Cosworth could be +35iat @400hp, the Harrop will be +60C and the Edblebrock +70C. 

Tuning: Here is my main disagreement. The Cosworth was tuned on an engine dyno and it specific to that kit. You cant take things Matt has done differently with their SC kit and apply them to the other kits. Its not just the engine dyno tuning either, they use widebands in every exhaust runner, and cylinder pressure sensors to properly dial in each cylinder and evaluate things like how well the stock knock sensor work ect.. Its a different kettle of fish. 

Tuner dont typically use widebands  and thermocouples in each cylinder runner, they just poke a wideband sensor up the exhaust. They certainly cant measure cylinder pressure and balance them out or evaluate if the knock sensor is doing a good job or not. 

For me the defining decision to go Cosworth was the tuning. Yes most people are happy with dyno or road tuning but for me I wanted the real deal OEM engineered solution. 

 

If I were choosing now, I would be on the fence a bit for some of the reasons Will has given and the fact that Cosworth are getting out of the game. Matt@cosworth still gives excellent support and he isnt likely to leave Cosworth any time soon as he is very well respected there, but you never know....

 

 

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Ade: I wonder why cossie decided to stop with their SC kit. Not enough demand? Imho their NA 1.3 setup was not sufficiently competitive price/performancy or top gains wise, but not so with SC 2.0, where they made good kit competitive enough and with several good points, including ones you mentioned. While i plan to stay NA, cossie SC would  have been my first choice if going FI.

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2 hours ago, Ade said:

I agree with some/most of the bits Will is saying but I will add a few (try to be non biased) to that.

Design c. I am not aware of anyone needing to cut a section, but yes you may need to put a small dent using a ball peen hammer.

Design e. Due to it compactness the intake runner lengths are not tuned properly. They are too short. This is one of the reasons why the Cosworth running 0.5bar makes the same power as the harrop running 0.7bar boost. The other reason is the bigger more draggy TVS and the tuning to balance cylinder pressure which can only be done with incylinder pressure sensors (standard tunnig with OEMs and serious motorsport).

Performance e. Its a fair point the most powerful Cosworth is their dev car running ~330hp. However, I am not aware of high power 400hp harrops that use pump gas? All E85 which help massively with high IATs. General advice I see is 12psi max on pump and you need E85 if you go for more boost due to heat and pulling timing. 

Cooling: Yes at 280hp both are fine, but running high power is where is were the nearly twice as good cooling (Coswroth is +15iat, harrop +25iat, Edlebrock +30iat) would come into it. Where the Cosworth could be +35iat @400hp, the Harrop will be +60C and the Edblebrock +70C. 

Tuning: Here is my main disagreement. The Cosworth was tuned on an engine dyno and it specific to that kit. You cant take things Matt has done differently with their SC kit and apply them to the other kits. Its not just the engine dyno tuning either, they use widebands in every exhaust runner, and cylinder pressure sensors to properly dial in each cylinder and evaluate things like how well the stock knock sensor work ect.. Its a different kettle of fish. 

Tuner dont typically use widebands  and thermocouples in each cylinder runner, they just poke a wideband sensor up the exhaust. They certainly cant measure cylinder pressure and balance them out or evaluate if the knock sensor is doing a good job or not. 

For me the defining decision to go Cosworth was the tuning. Yes most people are happy with dyno or road tuning but for me I wanted the real deal OEM engineered solution. 

 

If I were choosing now, I would be on the fence a bit for some of the reasons Will has given and the fact that Cosworth are getting out of the game. Matt@cosworth still gives excellent support and he isnt likely to leave Cosworth any time soon as he is very well respected there, but you never know....

 

 

This is interesting, I've not had to cut or dent anything for my fitment. I have a bit of hard rubber just to stop it wearing the paint.

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3 hours ago, Ade said:

Design e. Due to it compactness the intake runner lengths are not tuned properly. They are too short. This is one of the reasons why the Cosworth running 0.5bar makes the same power as the harrop running 0.7bar boost. The other reason is the bigger more draggy TVS and the tuning to balance cylinder pressure which can only be done with incylinder pressure sensors (standard tunnig with OEMs and serious motorsport).

That's interesting and not something I was aware of, have you got any more technical details on this?

 

3 hours ago, Ade said:

Tuning: Here is my main disagreement. The Cosworth was tuned on an engine dyno and it specific to that kit. You cant take things Matt has done differently with their SC kit and apply them to the other kits. Its not just the engine dyno tuning either, they use widebands in every exhaust runner, and cylinder pressure sensors to properly dial in each cylinder and evaluate things like how well the stock knock sensor work ect.. Its a different kettle of fish. 

Tuner dont typically use widebands  and thermocouples in each cylinder runner, they just poke a wideband sensor up the exhaust. They certainly cant measure cylinder pressure and balance them out or evaluate if the knock sensor is doing a good job or not. 

For me the defining decision to go Cosworth was the tuning. Yes most people are happy with dyno or road tuning but for me I wanted the real deal OEM engineered solution. 

I don't disagree with this, however they've developed a base tune, that works with their package. However not everyone is using the full Cosworth package, therefore it's no longer going to be producing the exact figures as Cosworth's development engine. 

I'd personally rather have a custom tune for my engine. 

 

 

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11 minutes ago, will300 said:

I'd personally rather have a custom tune for my engine.

 

Exactly that.  I've had my BRZ dyno tuned on every major mod and there is no real substitute, compared with base maps that don't quite match your car.

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1 hour ago, will300 said:

That's interesting and not something I was aware of, have you got any more technical details on this?

 

I don't disagree with this, however they've developed a base tune, that works with their package. However not everyone is using the full Cosworth package, therefore it's no longer going to be producing the exact figures as Cosworth's development engine. 

I'd personally rather have a custom tune for my engine. 

 

 

Well firstly perhaps you were not aware, Matt tweaks the maps to suit your engine. I think I had 3 or 4 iterations after installing my kits before it was spot on. Currently on the 8th iteration as ive added bits and ask for changes. This is over 3 years. 

Cosworth tested a variety of exhaust manifolds during testing/development. You've probably seen the H&S one doing the rounds, but they also tested a few other manifolds. So from that data Matt can customize the tune and tweak it. 

All you need to do is get some nice datalogs and send them and he will adjust accordingly. 

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1 hour ago, will300 said:

That's interesting and not something I was aware of, have you got any more technical details on this?

The length of the intake ports should be tuned to give you peak power where you want it. Higher rpm generally means longer runners for peak power. 

I dont know the exact numbers, but its part of the reason its such a big kit, the other being the large intercoolers.

Some OEMs like Mercedes have variable length intake manifolds so you dont have to compromise. 

Its a bit like variable valve timing. Years ago they were fixed and tuned to give peak power (torque at high rpm), then Honda came along with VVTI and their revy 8k rpm engines actually had usable torque lower down. 

 

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4 hours ago, Church said:

Ade: I wonder why cossie decided to stop with their SC kit. Not enough demand? Imho their NA 1.3 setup was not sufficiently competitive price/performancy or top gains wise, but not so with SC 2.0, where they made good kit competitive enough and with several good points, including ones you mentioned. While i plan to stay NA, cossie SC would  have been my first choice if going FI.

 48754693396_c1e95d8a18_b.jpg

 

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I've now spoken with Mark at Abbey Motorsport and he has been very helpful, answering my questions and sending me a quote by return.

I need to do some logistics planning but I'm now looking at the Harrop as my potential solution.  It all fits in with my use as a daily car, for road use only, mindful of a very progressive feel especially in the wet and the snow, near OEM installation looks and fairly quiet, making great use of the TD manifold and catback exhaust and HKS intake duct, retaining the stock 2nd cat, limiting the maximum torque in the map to preserve the engine and enjoying the charger's big engine feel.

Have I missed anything?

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I've now spoken with Mark at Abbey Motorsport and he has been very helpful, answering my questions and sending me a quote by return.
I need to do some logistics planning but I'm now looking at the Harrop as my potential solution.  It all fits in with my use as a daily car, for road use only, mindful of a very progressive feel especially in the wet and the snow, near OEM installation looks and fairly quiet, making great use of the TD manifold and catback exhaust and HKS intake duct, retaining the stock 2nd cat, limiting the maximum torque in the map to preserve the engine and enjoying the charger's big engine feel.
Have I missed anything?
Nope and you'll love it. It just feels like a 3 litre FA20.

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