8v V 16v

[taffycrook 2]

Sounds a daft question.

But I have two track day 205's.

One is a std 1.9 8v on 45's but lacks the grunt needed or expected. The other is a 1.6 8v but I have a alloy mi16 to slot in it.

The 8v has a lumpy cam vernier pulley and head work all to come. Still in the boxes as they have been for close on a year.

It will also feature 1.6 pistons to help with the CR.

SO a trick 8v.

The mi16 will be stock.

 

Which will be quicker?

 

The 8v is a track day slag only never gets used on the road the mi16 would be pressed into some daily use, hence the specs.

[petert 554]

Sounds a daft question.

But I have two track day 205's.

One is a std 1.9 8v on 45's but lacks the grunt needed or expected. The other is a 1.6 8v but I have a alloy mi16 to slot in it.

The 8v has a lumpy cam vernier pulley and head work all to come. Still in the boxes as they have been for close on a year.

It will also feature 1.6 pistons to help with the CR.

SO a trick 8v.

The mi16 will be stock.

 

Which will be quicker?

 

The 8v is a track day slag only never gets used on the road the mi16 would be pressed into some daily use, hence the specs.

 

The Mi16 is far more rewarding to drive and you'll battle to get 160hp out of a midly modified 8V. Provided you gear the Mi16 appropriately, it's a much nicer setup. The additional rev range is very usefulll. I'd keep the 8V as a road hack.

[James_R 3]

If you canmake the 8v scream like a 16v then use that. No surge issues really, otherwsie the Mi, but you'll find as soon as you go reasonable fast you'll watch the pressure needle swingable like it's in the wind.

[smckeown 1]

the 1.9 8v assuming it has the 1.9 box will have a high final drive that isn't really suitable to track work (unless it's a track with very high speeds) SO that will be slowing it down really.

 

The 1.6 car, assuming it has a 1.6 box has a better final drive but still not brilliant for an 8v or 16v, so a again that will be slowing it down.

 

I'd say the modded 1.9 8v should show more peak torque and the same peak power as the 16v, but power made much lower in the rev range (~6.5k vs 7k. That depends how good the headwork is though. So on that basis for a twisty track the 8v will be faster than the 16v, but on your average track the 16v will be king.

 

I'm assuming the modded 8v will hve the high compression to match the cam, which cam is it btw ?

 

Also on the basis the 1.9 8v is a dedicated track car you can go more extreme o nthe weight loss and suspension setup, which will make a good difference to a standard 1.6 running an mi16

[veloce200 3]

the 1.9 8v assuming it has the 1.9 box will have a high final drive that isn't really suitable to track work (unless it's a track with very high speeds) SO that will be slowing it down really.

 

The 1.6 car, assuming it has a 1.6 box has a better final drive but still not brilliant for an 8v or 16v, so a again that will be slowing it down.

 

I'd say the modded 1.9 8v should show more peak torque and the same peak power as the 16v, but power made much lower in the rev range (~6.5k vs 7k. That depends how good the headwork is though. So on that basis for a twisty track the 8v will be faster than the 16v, but on your average track the 16v will be king.

 

I'm assuming the modded 8v will hve the high compression to match the cam, which cam is it btw ?

 

Also on the basis the 1.9 8v is a dedicated track car you can go more extreme o nthe weight loss and suspension setup, which will make a good difference to a standard 1.6 running an mi16

 

there are a lot of doubters on here of the 8v. I was speaking again to a chap the other day and he confirmed that with his 70hp increase from 170hp 1.6 8v to 240hp MI he was no quicker at Lydden. FACT. At Brands it let go.... it was harder to drive with more power and torque so corner entry and exit were slower and negated the straightline speed. If you are planning on some serious g-force I'd stick with the 8v - easier, more reliable and outright speed is down to corner speed and how you lay the power down not outright hp and rev range... cue the angry MI posts again.... . Ulitimately he will get the MI to go faster but it will take more development time.

[James_R 3]

So you're really saying it's harder to drive he's not got it yet really? more driver than the engine underhim effecting the car's time?

[VisaGTi16v 1]

I know the Brents have had terrible luck with their new 16v's but I dont see how it can be slower than his 8v. You dont have to use all the power so if traction is the issue then surely less throttle is the answer and therefore corner speed should be unaffected. You will only be on partial throttle through most of a corner. Its not like its a turbo car and its going on/off boost mid corner. I can only think that they have sacrificed driveability and a wide torque band for outright power which is making it worse overall, especially at somewhere like Lydden with its hills, dropping off cam etc

[pdd144c 0]

Richard has said he needs to change his car setup to cope with his new engine. He managed a 0.7 second improvement on his lap time from last year at Snetterton this weekend, but it is a power circuit so perhaps you can't read into that too much... He's a cracking driver, I'm sure he'll have the best out of it soon.

[VisaGTi16v 1]

Steve said it was a bit moist up there on Sunday!!! I did a sprint there back in 2002 or something and had a calculated 118 down the back straight in the wet which was interesting, especially when I got round the left hander then into the tight right

 

Richard was quickest fwd in both races, doing better than in qualifying so sounds like he raced well..

Edited May 31, 2007 by VisaGTi16v

[pdd144c 0]

Was very wet, our RS500 was spinning wheels at over 140mph!

[C_W 3 1 Cars]

Unless it's one of these 8v's that actually produces the poke, I'd go for standard Mi16.

[veloce200 3]

So you're really saying it's harder to drive he's not got it yet really? more driver than the engine underhim effecting the car's time?

no not really as in the 1.6 he beat most cars 2 classes above

[Anulfo 22]

no not really as in the 1.6 he beat most cars 2 classes above

Don't underestimate the effect of gearing to your car.I race a fully prepared 1.9 8valve 205 and at the moment its running an Mi 16 final drive which gives it a ratio of about 4.4:1.Not very good for top speed but on the track it will easily outsprint most of the 16valve conversions that i have come up against.I've found the 8 valvers (1.6 and 1.9) to be fantastic little cars with plenty of grunt lower down the rev range.Did you mention at the start about putting 1.6 pistons into a 1.9 to raise the CR?

[Baz 421]

Yes but a 16v with the same FDR would then be much better no? Also lending the ability to keep it on the power band more, but as you say at a sacrifice of top speed.

[niklas 1]

It takes a lot of money to make the 8v as quick as the 16v, in standard tune or mildly tuned it's not even close!

 

EDIT: What does it take to make the 130bhp ja produce equivalently to the 160 bhp j4; cams, carbs and raised cr?

For the same amount of money, minus conversion costs, the j4 will easily keep its edge! Besides the higher tune the better (and in the end cheaper) the 16v will respond compared to the 8v!

Edited June 22, 2007 by niklas

[deadcatdave 0]

It takes a lot of money to make the 8v as quick as the 16v, in standard tune or mildly tuned it's not even close!

 

EDIT: What does it take to make the 130bhp ja produce equivalently to the 160 bhp j4; cams, carbs and raised cr?

For the same amount of money, minus conversion costs, the j4 will easily keep its edge! Besides the higher tune the better (and in the end cheaper) the 16v will respond compared to the 8v!

 

I've done somew research on this ery subject, here are my figures

 

 

 

-------------------------------------------------------------power (bhp)--total cost--full bottom rebuild---head rebuild--head port and rebuild--cams--TBs/ECU/remap

full mi16 bottom rebuild, and head rebuild (no work)----160----------£1,850------£1,500----------------£350----------£0---------------------£0----£0

rebuild 8v with head and TBs------------------------------190----------£4,670------£1,500----------------£0------------£1,000-----------------£170--£2,000

rebuild mi16 with ecu/tbs, standard cams----------------200----------£4,020------£1,500----------------£350----------£0---------------------£170--£2,000

rebuild mi16 with ecu/tbs, new cams & headwork--------220----------£4,540------£1,500----------------£0------------£700-------------------£340--£2,000

[Anulfo 22]

I've done somew research on this ery subject, here are my figures

-------------------------------------------------------------power (bhp)--total cost--full bottom rebuild---head rebuild--head port and rebuild--cams--TBs/ECU/remap

full mi16 bottom rebuild, and head rebuild (no work)----160----------£1,850------£1,500----------------£350----------£0---------------------£0----£0

rebuild 8v with head and TBs------------------------------190----------£4,670------£1,500----------------£0------------£1,000-----------------£170--£2,000

rebuild mi16 with ecu/tbs, standard cams----------------200----------£4,020------£1,500----------------£350----------£0---------------------£170--£2,000

rebuild mi16 with ecu/tbs, new cams & headwork--------220----------£4,540------£1,500----------------£0------------£700-------------------£340--£2,000

Power costs!!!Theres no doubt about that.Whether its an 8v oor 16v tuning isn't a cheap hobby!