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Not impressed after rolling road!


supraszr

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Anyone with a car can do the same bud. Bit of NOS is all it takes :)

 

Can't say it would or wouldn't run as well as the other members because of the high figures ;)

 

Very true dude, cant believe this post has gone so mental. I think after all this my car just needs a good serivice and maybe a play around with when on the rollers, Gonna take it to Alan Jeffrey in Plymouth I think.

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What are your goals bud? If its BHP (useless for any kind of increase in acceleration) then having the exhaust system, breathing system in general, as free flowing as possible is your best bet.

 

If its torque (read acceleration) you are after then its better to have a bit of back pressure from the exhaust system so therefor its better to leave the cats in.

 

Higher BHP will mean higher top speed but less torque meaning less acceleration. More torque will mean lower top speed and less BHP but the acceleration will be better.

 

A full service with decent fluids should definitely be on the cards if it hasn't been done in a while. It can go a long way. Has it had a wheel alignment? If not get it done properly, just makes the car more fun and safe with the power it has.

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What are your goals bud? If its BHP (useless for any kind of increase in acceleration) then having the exhaust system, breathing system in general, as free flowing as possible is your best bet.

 

If its torque (read acceleration) you are after then its better to have a bit of back pressure from the exhaust system so therefor its better to leave the cats in.

 

Higher BHP will mean higher top speed but less torque meaning less acceleration. More torque will mean lower top speed and less BHP but the acceleration will be better.

 

A full service with decent fluids should definitely be on the cards if it hasn't been done in a while. It can go a long way. Has it had a wheel alignment? If not get it done properly, just makes the car more fun and safe with the power it has.

 

Cheers for the normal response, Im after acceleration to be honest and I dont think my current exhaust is doing me any favours. Not worried about top end really not for driving round Devon lol.:D

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You want to get the back pressure back them.

 

Double cat's will sort that for you, the exhaust won't really make a difference with them in. Another option is a more restrictive exhaust with double de-cats.

 

Cheers Bud Thanks for your help:thumbs:

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Oh, you want the intake with the least amount of resistance you can get. A stock airbox with a decent filter will do the job nicely (helps against heatsoak).

 

Other than that i can only recommend the airbox i have which is an ARC one. You want a filter with heatshielding of some sort, stock is considered the best... my opinion is different ;)

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Reason being is that with a 3mm headgasket you will get the same compression ratio as a TT.

 

Aaaargh. OK you started well but then came out with this wonder. Do you know what's ranked as the number one worst way to change compression ratio? Thicker head gasket. Corky Bell gives precisely one sentence to the subject, basically "Don't even think of doing something stupid like using a thicker head gasket". Pistons are the only real cost effective way to change compression ratio as you can form them so as not to change the squish band. You can drop the compression ratio with a thicker head gasket and yet cock up the squish band to the point that you end up with more chance of detonation than before.

 

I also can't believe you can get a long term seal, controlled deformation, or consistent torque figures across the board when wedging in such a mattress-sized head gasket.

 

Secondly the TT offers one drawback (imo ) that it has only one wastegate, being in the #1 turbo. Therefore if you are to tune a TT (tuning turbo wise) you must start from scratch less the 3mm headgasket. But comparing the prices of NA's and TT's the price is cost effective for a 3mm head gasket.

 

I've got no idea what your point is here. If you rely on the stock wastegate that infers you are keeping the stock turbos. Ergo to bring the NA up to the same spec you need to fit an entire sequential system :blink: But if you're fitting a single turbo to the NA, then a direct comparision would be fitting a single turbo to the TT - in which case the stock wastegate leaves the engine bay along with turbo #1, rendering your comment about the wastegate moot in both cases. And what "starting from scratch" means in that case I do not know.

 

I'm sorry to have to hack into your first post, it's well written but it's just wrong :) And to add to that there are numerous differences between the base engines that cause problems when it comes to turbocharging. Such as:

  • No positive MAP sensor and an ECU that has no idea about positive pressure.
  • Different fuel system.
  • No oil squirters for the pistons.
  • Different cylinder head and intake setup geared strictly for NA operation.

The ignition system is a bugger as well, it's a distributor setup which has these drawbacks for turbocharging:

  • It gets in the way of the turbo setup
  • You can't electronically control the timing anywhere near the way you can on the coil-on-plug system on a TT
  • It's hard to provide the spark energy for higher boost levels as there is but one coil firing every ignition event

 

Now if you've lunched a piston I'd be all for thinking about swapping in a good short motor from an NA, and if you've got plans to strip out and re-plumb all the ignition, ECU, fuel system etc anyway I'd say an NA would be an excellent starting point. But if you're just a normal punter who wants turbo power and the option of going mad in the future, it's TT all the way for an easy life.

 

-Ian

Edited by Ian C (see edit history)
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What are your goals bud? If its BHP (useless for any kind of increase in acceleration) then having the exhaust system, breathing system in general, as free flowing as possible is your best bet.

 

If its torque (read acceleration) you are after then its better to have a bit of back pressure from the exhaust system so therefor its better to leave the cats in.

 

Higher BHP will mean higher top speed but less torque meaning less acceleration. More torque will mean lower top speed and less BHP but the acceleration will be better.

 

 

*cracks knuckles* Right :)

 

Back pressure is a myth, it's exhaust pulse tuning that causes power band changes, and this mostly happens in the headers and collector. Back pressure is always bad. I'm not going into it here, have a searchy.

 

BHP is a function of torque, acceleration is a function of the torque curve. Area under the curve is a measurement of the overall performance of an engine. Attempting to divorce top speed from acceleration and BHP from torque is madness. Madness I say.

 

-Ian

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Guest Rays the roof
Anyone with a car can do the same bud. Bit of NOS is all it takes :)

 

Anyone??

 

Anyone can fit it, but it took me over 20 runs on the strip to get the optimum jet ratio Nitrous/fuel ;)

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*cracks knuckles* Right :)

 

Back pressure is a myth, it's exhaust pulse tuning that causes power band changes, and this mostly happens in the headers and collector. Back pressure is always bad. I'm not going into it here, have a searchy.

 

BHP is a function of torque, acceleration is a function of the torque curve. Area under the curve is a measurement of the overall performance of an engine. Attempting to divorce top speed from acceleration and BHP from torque is madness. Madness I say.

 

-Ian

 

Well said,

I was about to say something but luckily i carried on reading.

 

Im fully decat with manifold in my N/A and it has much better acceleration than a N/A with both cats in

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  • 3 weeks later...

find some decent rollers :D i always use the same ones just to know the gains etc. as all dyno's are slightly different. (obviously i can't help the weather when i do the tests so temp is dif)

 

also not sure if it was mentioned cause i kinda skimmed but are you sure it was at the flywheel or was 20% loss not calculated (i think its 20% in RWD correct me if i'm wrong :D)

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*cracks knuckles* Right :)

 

Back pressure is a myth, it's exhaust pulse tuning that causes power band changes, and this mostly happens in the headers and collector. Back pressure is always bad. I'm not going into it here, have a searchy.

 

BHP is a function of torque, acceleration is a function of the torque curve. Area under the curve is a measurement of the overall performance of an engine. Attempting to divorce top speed from acceleration and BHP from torque is madness. Madness I say.

 

-Ian

 

You sound like a scientist! :D

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*cracks knuckles* Right :)

 

Back pressure is a myth, it's exhaust pulse tuning that causes power band changes, and this mostly happens in the headers and collector. Back pressure is always bad. I'm not going into it here, have a searchy.

 

BHP is a function of torque, acceleration is a function of the torque curve. Area under the curve is a measurement of the overall performance of an engine. Attempting to divorce top speed from acceleration and BHP from torque is madness. Madness I say.

 

-Ian

 

Just noticed this lol.

 

I know that its not as simple as what i put, i didn't know the graphic details but i knew the jist of what you put. I just thought i would help out with the real life gains of exhausts and filters without going into the physics of what is happening.

 

With N/A engines BHP gains through exhausts and filters lead to less torque. I've never known the precise reason for this but its just a given as far as i know.

 

I read that BHP is the rate at which the internals of the engine can be accelerated given their weight, and the torque is the force with which the crank is being rotated. Diesels are torquey due to heavier internals and more forceful combustion but have less BHP due to the said weight of internals and the more power required to accelerate them.

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