sr5 vs sr8 rear end?

sr5 vs sr8 rear end?

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shirt

Original Poster:

23,467 posts

208 months

Saturday 24th August 2019
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i'm putting an ecoboost and hewland ftr200 into an SR8 chassis. just read that the SR5 has the hewland jfr200 transaxle which is identical to the ftr other than the omission of the latter's integrated engine dry sump tank.

are the suspension main dimensions and upright design the same on both cars? i.e. can i use SR5 driveshafts? or is there a better/cheaper/stronger alternative?

MK3 Dan

273 posts

152 months

Monday 26th August 2019
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I am fairly sure that the SR5 used a slightly modified SR8 chassis.

I believe the gearbox was the same, just with different ratios.

SR8 had an oil tank as part of engine bell housing, SR5 was separate oil tank like the SR3.

anonymous-user

61 months

Monday 26th August 2019
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If I remember correctly the first couple of SR8s came with the JFR installed.

shirt

Original Poster:

23,467 posts

208 months

Monday 26th August 2019
quotequote all
I thought the sr8’s had a quaife box? That’s what was fitted originally (seller took the engine and box for a mental exige project). I emailed quaife when I was looking for a transaxle and they wouldn’t answer any questions / referred me to radical.

I’m told the uprights for sr3/5/8 are all the same? Also told radical shafts are made of chocolate so best just to measure everything up and get a set made.

anonymous-user

61 months

Tuesday 27th August 2019
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During the 1st (and 2nd?) year of production SR8s came with a Hewland-Box installed. But the Hewland-Box couldn't cope very well with the amount of tourqe delivered. Regarding the weight and high center of gravity some drivers didn't like the Quaife-Box very much.

parsonsj

49 posts

97 months

Sunday 1st September 2019
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I like your plan, but I think the Ecoboost engine creates more torque (350 lb-ft) than the JFR(FTR)200 rating (about 235 lb-ft, if memory serves).

The Quaife/Powertec has a similar rating to the JFR(FTR)200 though there are two models of the Quaife. The early version of the Quaife (QBE58G) had consistent crown gear issues and was replaced with a slightly stronger version (QBE72G) which remains in use today.

If I might suggest an alternative to the Ecoboost, I'd look at a naturally aspirated Honda K20 or K24 (like a real SR5). It has much lower torque (195-220) and can get to 300hp with the right parts and rpm.

Edited by parsonsj on Sunday 1st September 03:53

shirt

Original Poster:

23,467 posts

208 months

Sunday 1st September 2019
quotequote all
I believe the fiesta ST180's are 178bhp and 180 lbs/ft stock. mygale's formula ford puts out 200bhp / ? lbs/ft using the FTR200 and some of the hillclimb guys have tuned these to 320+ with no issues reported in terms of reliability.

i looked at many options [subaru flat 4, jag v6, rotary, k20] but i'm firmly in the ecoboost camp now as i bought all the bits from mygale [bellhousing, clutch shaft and all the engine-to-gearbox dry sump connections, breathers etc.] which arrived last thursday. i also have a jenvey turbo manifold made for this engine.

it's a light engine and 300bhp is achievable stock, just with a decent ecu and turbo. a blown engine is therefore a manageable $ proposition whereas a blown k20 [which i've seen many happen to other people] is not. the main driver for this project was creating something that can best an SR3 whilst having much lower running costs.

i do need to understand the gearbox a bit better and what needs to be done in terms of in-gear boost strategy to make sure it doesn't lunch itself. just hewland were less than helpful when i initially contacted them [although i do need to buy new ratios now, so that may improve] so prob need to get on uphillracers and ask questions.



Edited by shirt on Sunday 1st September 14:25

parsonsj

49 posts

97 months

Sunday 1st September 2019
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Please do post your progress as it happens!

I've got a pair of SR8s, one of which is down due to gearbox/crown gear issues (it has the 58G, naturally) and I'm looking for ideas for how to fix it or otherwise make it move under its own power again.


shirt

Original Poster:

23,467 posts

208 months

Sunday 1st September 2019
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as soon as i get an engine i will start a build thread as i have an absolute ton of questions. the car is stripped to bare chassis waiting to get going and i've finished/sold my other projects to enable it.

i believe precision chassis works over there [US] did an sr3 subaru conversion. it was that build which gave me the idea, then this rolling chassis came up cheap. i do think the ecoboost is a better solution though. modern DI turbo tuning possibilities, easy power, decent fuel economy, and a strong/balanced bottom end will rev to 8.5k